Getting Started

Note that we support Android 4.0 and higher. You can also check out our API Reference for more detailed information about our SDK.

Installation

Step 1: Download Parse-SDK-Android

Dependency

Add this in your root build.gradle file (not your module build.gradle file):

allprojects {
	repositories {
		...
		maven { url "https://jitpack.io" }
	}
}

Then, add the library to your project build.gradle

dependencies {
    implementation "com.github.parse-community.Parse-SDK-Android:parse:latest.version.here"
}

with the latest version being

Step 2: Setup Parse Initialize Parse using your server configuration:

import com.parse.Parse;
import android.app.Application;

public class App extends Application {
  @Override
  public void onCreate() {
    super.onCreate();
    Parse.initialize(new Parse.Configuration.Builder(this)
      .applicationId("YOUR_APP_ID")
      // if defined
      .clientKey("YOUR_CLIENT_KEY")
      .server("http://localhost:1337/parse/")
      .build()
    );
  }
}

The custom Application class must be registered in AndroidManifest.xml:

 <application
   android:name=".App"
   ...>
   ...
 </application>

Note that if you are testing with a server using http, you will need to add android:usesCleartextTraffic="true" to your above <application> definition, but you should only do this while testing and should use https for your final product.

Objects

The ParseObject

Storing data on Parse is built around the ParseObject. Each ParseObject contains key-value pairs of JSON-compatible data. This data is schemaless, which means that you don’t need to specify ahead of time what keys exist on each ParseObject. You simply set whatever key-value pairs you want, and our backend will store it.

For example, let’s say you’re tracking high scores for a game. A single ParseObject could contain:

score: 1337, playerName: "Sean Plott", cheatMode: false

Keys must be alphanumeric strings. Values can be strings, numbers, booleans, or even arrays and objects - anything that can be JSON-encoded.

Each ParseObject has a class name that you can use to distinguish different sorts of data. For example, we could call the high score object a GameScore. We recommend that you NameYourClassesLikeThis and nameYourKeysLikeThis, just to keep your code looking pretty.

Saving Objects

Let’s say you want to save the GameScore described above to your Parse Server. The interface is similar to a Map, plus the saveInBackground method:

ParseObject gameScore = new ParseObject("GameScore");
gameScore.put("score", 1337);
gameScore.put("playerName", "Sean Plott");
gameScore.put("cheatMode", false);
gameScore.saveInBackground();

After this code runs, you will probably be wondering if anything really happened. To make sure the data was saved, you can look at the Data Browser in your app on Parse. You should see something like this:

{
  "objectId": "xWMyZ4YEGZ",
  "score": 1337,
  "playerName": "Sean Plott",
  "cheatMode": false,
  "createdAt":"2022-01-01T12:23:45.678Z",
  "updatedAt":"2022-01-01T12:23:45.678Z"
}

There are two things to note here. You didn’t have to configure or set up a new Class called GameScore before running this code. Your Parse app lazily creates this Class for you when it first encounters it.

There are also a few fields you don’t need to specify that are provided as a convenience. objectId is a unique identifier for each saved object. createdAt and updatedAt represent the time that each object was created and last modified in the cloud. Each of these fields is filled in by Parse, so they don’t exist on a ParseObject until a save operation has completed.

Retrieving Objects

Saving data to the cloud is fun, but it’s even more fun to get that data out again. If you have the objectId, which is available once the ParseObject been uploaded to the server, you can retrieve the whole ParseObject using a ParseQuery:

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.getInBackground("xWMyZ4YEGZ", new GetCallback<ParseObject>() {
  public void done(ParseObject object, ParseException e) {
    if (e == null) {
      // object will be your game score
    } else {
      // something went wrong
    }
  }
});

To get the values out of the ParseObject, there’s a getX method for each data type:

int score = gameScore.getInt("score");
String playerName = gameScore.getString("playerName");
boolean cheatMode = gameScore.getBoolean("cheatMode");

If you don’t know what type of data you’re getting out, you can call get(key), but then you probably have to cast it right away anyways. In most situations you should use the typed accessors like getString.

The four special values have their own accessors:

String objectId = gameScore.getObjectId();
Date updatedAt = gameScore.getUpdatedAt();
Date createdAt = gameScore.getCreatedAt();
ParseACL acl = gameScore.getACL();

If you need to refresh an object you already have with the latest data that is in the cloud, you can call the fetchInBackground method like so:

myObject.fetchInBackground(new GetCallback<ParseObject>() {
  public void done(ParseObject object, ParseException e) {
    if (e == null) {
      // Success!
    } else {
      // Failure!
    }
  }
});

The code in the GetCallback will be run on the main thread.

The Local Datastore

Parse also lets you store objects in a local datastore on the Android device itself. You can use this for data that doesn’t need to be saved to the cloud, but this is especially useful for temporarily storing data so that it can be synced later. To enable the datastore, call Parse.enableLocalDatastore() in your Application constructor before calling Parse.initialize(). Once the local datastore is enabled, you can store an object by pinning it.

ParseObject gameScore = new ParseObject("GameScore");
gameScore.put("score", 1337);
gameScore.put("playerName", "Sean Plott");
gameScore.put("cheatMode", false);
gameScore.pinInBackground();

As with saving, this recursively stores every object and file that gameScore points to, if it has been fetched from the cloud. Whenever you save changes to the object, or fetch new changes from Parse, the copy in the datastore will be automatically updated, so you don’t have to worry about it.

Retrieving Objects from the Local Datastore

Storing an object is only useful if you can get it back out. To get the data for a specific object, you can use a ParseQuery just like you would while on the network, but using the fromLocalDatastore method to tell it where to get the data.

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.fromLocalDatastore();
query.getInBackground("xWMyZ4YEGZ", new GetCallback<ParseObject>() {
  public void done(ParseObject object, ParseException e) {
    if (e == null) {
      // object will be your game score
    } else {
      // something went wrong
    }
  }
});

If you already have an instance of the object, you can instead use the fetchFromLocalDatastoreInBackground method.

ParseObject object = ParseObject.createWithoutData("GameScore", "xWMyZ4YEGZ");
object.fetchFromLocalDatastoreInBackground(new GetCallback<ParseObject>() {
  public void done(ParseObject object, ParseException e) {
    if (e == null) {
      // object will be your game score
    } else {
      // something went wrong
    }
  }
});

Unpinning Objects

When you are done with the object and no longer need to keep it on the device, you can release it with unpinInBackground.

gameScore.unpinInBackground();

Saving Objects Offline

Most save functions execute immediately, and inform your app when the save is complete. If you don’t need to know when the save has finished, you can use saveEventually instead. The advantage is that if the user currently doesn’t have a network connection, saveEventually will store the update on the device until a network connection is re-established. If your app is closed before the connection is back, Parse will try again the next time the app is opened. All calls to saveEventually (and deleteEventually) are executed in the order they are called, so it is safe to call saveEventually on an object multiple times. If you have the local datastore enabled, then any object you saveEventually will be pinned as long as that save is in progress. That makes it easy to retrieve your local changes while waiting for the network to be available.

ParseObject gameScore = new ParseObject("GameScore");
gameScore.put("score", 1337);
gameScore.put("playerName", "Sean Plott");
gameScore.put("cheatMode", false);
gameScore.saveEventually();

Updating Objects

Updating an object is simple. Just set some new data on it and call one of the save methods. Assuming you have saved the object and have the objectId, you can retrieve the ParseObject using a ParseQuery and update its data:

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");

// Retrieve the object by id
query.getInBackground("xWMyZ4YEGZ", new GetCallback<ParseObject>() {
  public void done(ParseObject gameScore, ParseException e) {
    if (e == null) {
      // Now let's update it with some new data. In this case, only cheatMode and score
      // will get sent to your Parse Server. playerName hasn't changed.
      gameScore.put("score", 1338);
      gameScore.put("cheatMode", true);
      gameScore.saveInBackground();
    }
  }
});

Parse automatically figures out which data has changed so only “dirty” fields will be transmitted during a save. You don’t need to worry about squashing data in the cloud that you didn’t intend to update.

Counters

The above example contains a common use case. The “score” field is a counter that we’ll need to continually update with the player’s latest score. Using the above method works but it’s cumbersome and can lead to problems if you have multiple clients trying to update the same counter.

To help with storing counter-type data, Parse provides methods that atomically increment (or decrement) any number field. So, the same update can be rewritten as:

gameScore.increment("score");
gameScore.saveInBackground();

You can also increment by any amount using increment(key, amount).

Arrays

To help with storing array data, there are three operations that can be used to atomically change an array field:

• add and addAll append the given objects to the end of an array field.
• addUnique and addAllUnique add only the given objects which aren’t already contained in an array field to that field. The position of the insert is not guaranteed.
• removeAll removes all instances of the given objects from an array field.

For example, we can add items to the set-like “skills” field like so:

gameScore.addAllUnique("skills", Arrays.asList("flying", "kungfu"));
gameScore.saveInBackground();

Note that it is not currently possible to atomically add and remove items from an array in the same save. You will have to call save in between every different kind of array operation.

Deleting Objects

To delete an object from your Parse Server:

myObject.deleteInBackground();

If you want to run a callback when the delete is confirmed, you can provide a DeleteCallback to the deleteInBackground method. If you want to block the calling thread, you can use the delete method.

You can delete a single field from an object with the remove method:

// After this, the playerName field will be empty
myObject.remove("playerName");

// Saves the field deletion to your Parse Server
myObject.saveInBackground();

Relational Data

Objects can have relationships with other objects. To model this behavior, any ParseObject can be used as a value in other ParseObjects. Internally, the Parse framework will store the referred-to object in just one place, to maintain consistency.

For example, each Comment in a blogging app might correspond to one Post. To create a new Post with a single Comment, you could write:

// Create the post
ParseObject myPost = new ParseObject("Post");
myPost.put("title", "I'm Hungry");
myPost.put("content", "Where should we go for lunch?");

// Create the comment
ParseObject myComment = new ParseObject("Comment");
myComment.put("content", "Let's do Sushirrito.");

// Add a relation between the Post and Comment
myComment.put("post", myPost);

// This will save both myPost and myComment
myComment.saveInBackground();

You can also link objects using just their objectIds like so:

// Add a relation between the Post with objectId "1zEcyElZ80" and the comment
myComment.put("post", ParseObject.createWithoutData("Post", "1zEcyElZ80"));

By default, when fetching an object, related ParseObjects are not fetched. These objects’ values cannot be retrieved until they have been fetched like so:

fetchedComment.getParseObject("post")
    .fetchIfNeededInBackground(new GetCallback<ParseObject>() {
        public void done(ParseObject post, ParseException e) {
          String title = post.getString("title");
          // Do something with your new title variable
        }
    });

You can also model a many-to-many relation using the ParseRelation object. This works similar to List<ParseObject>, except that you don’t need to download all the ParseObjects in a relation at once. This allows ParseRelation to scale to many more objects than the List<ParseObject> approach. For example, a User may have many Posts that they might like. In this case, you can store the set of Posts that a User likes using getRelation. In order to add a post to the list, the code would look something like:

ParseUser user = ParseUser.getCurrentUser();
ParseRelation<ParseObject> relation = user.getRelation("likes");
relation.add(post);
user.saveInBackground();

You can remove a post from the ParseRelation with something like:

relation.remove(post);

By default, the list of objects in this relation are not downloaded. You can get the list of Posts by calling findInBackground on the ParseQuery returned by getQuery. The code would look like:

relation.getQuery().findInBackground(new FindCallback<ParseObject>() {
    void done(List<ParseObject> results, ParseException e) {
      if (e != null) {
        // There was an error
      } else {
        // results have all the Posts the current user liked.
      }
    }
});

If you want only a subset of the Posts you can add extra constraints to the ParseQuery returned by getQuery. The code would look something like:

ParseQuery<ParseObject> query = relation.getQuery();
// Add other query constraints.

For more details on ParseQuery, please look at the query portion of this guide. A ParseRelation behaves similar to a List<ParseObject> for querying purposes, so any queries you can do on lists of objects (other than include) you can do on ParseRelation.

Data Types

So far we’ve used values with type String, Integer, boolean, and ParseObject. Parse also supports float, java.util.Date, and JSONObject.NULL.

You can nest JSONObject and JSONArray objects to store more structured data within a single ParseObject. Overall, the following types are allowed for each field in your object:

• String => String
• Number => primitive numeric values such as ints, doubles, longs, or floats
• Bool => boolean
• Array => JSONArray
• Object => JSONObject
• Date => java.util.Date
• File => ParseFile
• Pointer => other ParseObject
• Relation => ParseRelation
• Null => JSONObject.NULL

Some examples:

int myNumber = 42;
String myString = "the number is " + myNumber;
Date myDate = new Date();

JSONArray myArray = new JSONArray();
myArray.put(myString);
myArray.put(myNumber);

JSONObject myObject = new JSONObject();
myObject.put("number", myNumber);
myObject.put("string", myString);

ParseObject bigObject = new ParseObject("BigObject");
bigObject.put("myNumber", myNumber);
bigObject.put("myString", myString);
bigObject.put("myDate", myDate);
bigObject.put("myArray", myArray);
bigObject.put("myObject", myObject);
bigObject.put("myNull", JSONObject.NULL);
bigObject.saveInBackground();

We do not recommend storing large pieces of binary data like images or documents on ParseObject. We recommend you use ParseFiles to store images, documents, and other types of files. You can do so by instantiating a ParseFile object and setting it on a field. See Files for more details.

For more information about how Parse handles data, check out our documentation on Data.

Subclasses

Parse is designed to get you up and running as quickly as possible. You can access all of your data using the ParseObject class and access any field with get(). In mature codebases, subclasses have many advantages, including terseness, extensibility, and support for autocomplete. Subclassing is completely optional, but can transform this code:

ParseObject shield = new ParseObject("Armor");
shield.put("displayName", "Wooden Shield");
shield.put("fireproof", false);
shield.put("rupees", 50);

Into this:

Armor shield = new Armor();
shield.setDisplayName("Wooden Shield");
shield.setFireproof(false);
shield.setRupees(50);

Subclassing ParseObject

To create a ParseObject subclass:

1. Declare a subclass which extends ParseObject.
2. Add a @ParseClassName annotation. Its value should be the string you would pass into the ParseObject constructor, and makes all future class name references unnecessary.
3. Ensure that your subclass has a public default (i.e. zero-argument) constructor. You must not modify any ParseObject fields in this constructor.
4. Call ParseObject.registerSubclass(YourClass.class) in your Application constructor before calling Parse.initialize(). The following code successfully implements and registers the Armor subclass of ParseObject:

// Armor.java
import com.parse.ParseObject;
import com.parse.ParseClassName;

@ParseClassName("Armor")
public class Armor extends ParseObject {
}

// App.java
import com.parse.Parse;
import android.app.Application;

public class App extends Application {
  @Override
  public void onCreate() {
    super.onCreate();

    ParseObject.registerSubclass(Armor.class);
    Parse.initialize(this);
  }
}

Accessors, Mutators, and Methods

Adding methods to your ParseObject subclass helps encapsulate logic about the class. You can keep all your logic about a subject in one place rather than using separate classes for business logic and storage/transmission logic.

You can add accessors and mutators for the fields of your ParseObject easily. Declare the getter and setter for the field as you normally would, but implement them in terms of get() and put(). The following example creates a displayName field in the Armor class:

// Armor.java
@ParseClassName("Armor")
public class Armor extends ParseObject {
  public String getDisplayName() {
    return getString("displayName");
  }
  public void setDisplayName(String value) {
    put("displayName", value);
  }
}

You can now access the displayName field using armor.getDisplayName() and assign to it using armor.setDisplayName("Wooden Sword"). This allows your IDE to provide autocompletion as you develop your app and allows typos to be caught at compile-time.

Accessors and mutators of various types can be easily defined in this manner using the various forms of get() such as getInt(), getParseFile(), or getMap().

If you need more complicated logic than simple field access, you can declare your own methods as well:

public void takeDamage(int amount) {
  // Decrease the armor's durability and determine whether it has broken
  increment("durability", -amount);
  if (getDurability() < 0) {
    setBroken(true);
  }
}

Initializing Subclasses

You should create new instances of your subclasses using the constructors you have defined. Your subclass must define a public default constructor that does not modify fields of the ParseObject, which will be used throughout the Parse SDK to create strongly-typed instances of your subclass.

To create a reference to an existing object, use ParseObject.createWithoutData():

Armor armorReference = ParseObject.createWithoutData(Armor.class, armor.getObjectId());

Queries on Subclasses

You can get a query for objects of a particular subclass using the static method ParseQuery.getQuery(). The following example queries for armors that the user can afford:

ParseQuery<Armor> query = ParseQuery.getQuery(Armor.class);
query.whereLessThanOrEqualTo("rupees", ParseUser.getCurrentUser().get("rupees"));
query.findInBackground(new FindCallback<Armor>() {
  @Override
  public void done(List<Armor> results, ParseException e) {
    for (Armor a : results) {
      // ...
    }
  }
});

Parcelable

As most public facing components of the SDK, ParseObject implements the Parcelable interface. This means you can retain a ParseObject during configuration changes, or pass objects to other components through Bundles. To achieve this, depending on the context, use either Parcel#writeParcelable(Parcelable, int) or Bundle#putParcelable(String, Parcelable). For instance, in an Activity,

private ParseObject object;

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelable("object", object);
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
  if (savedInstanceState != null) {
    object = (ParseObject) savedInstanceState.getParcelable("object");
  }
}

That’s it. ParseObject will parcel its internal state, along with unsaved children and dirty changes. There are, however, a few things to be aware of when parceling objects that have ongoing operations, like save or delete. The SDK behavior differs depending on whether you have enabled the Local Datastore.

Parceling with Local Datastore enabled

When the Local Datastore is enabled, parceling a ParseObject is a safe operation even if there are ongoing save or delete operations. Thanks to LDS, the same instance is returned when unparceling (unless something happens in the middle, in which case the SDK behaves as if LDS was disabled, see below).

This means that the ParseObject is internally notified about the operation results, whether it’s successful or not. There is, however, no way to register external callbacks (SaveCallback or DeleteCallback) for these tasks, other than the ones you have already registered at the moment of saving / deleting the source instance.

Parceling with Local Datastore disabled

When the Local Datastore is disabled, and the parceled ParseObject has ongoing operations that haven’t finished yet, the unparceled object will end up in a stale state. The unparceled object, being a different instance than the source object,

• assumes that ongoing operations at the moment of parceling never took place
• will not update its internal state when the operations triggered by the source object

The unfortunate consequence is that keys that were dirty before saving will still be marked as dirty for the unparceled object. This means, for instance, that any future call to saveInBackground() will send these dirty operations to the server again. This can lead to inconsistencies for operations like increment, since it might be performed twice.

Parceling ParseObject subclasses

By default, ParseObject implementation parcels everything that is needed. If your subclasses have stateful information that you would like to keep when parceling, you can simply override onSaveInstanceState(Bundle) and onRestoreInstanceState(Bundle):

// Armor.java
@ParseClassName("Armor")
public class Armor extends ParseObject {
  private int member;

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    outState.putInt("member", member);
  }

  @Override
  protected void onRestoreInstanceState(Bundle savedInstanceState) {
    member = savedInstanceState.getInt("member");
  }
}

Queries

We’ve already seen how a ParseQuery with getInBackground can retrieve a single ParseObject from Parse. There are many other ways to retrieve data with ParseQuery - you can retrieve many objects at once, put conditions on the objects you wish to retrieve, cache queries automatically to avoid writing that code yourself, and more.

Basic Queries

In many cases, getInBackground isn’t powerful enough to specify which objects you want to retrieve. The ParseQuery offers different ways to retrieve a list of objects rather than just a single object.

The general pattern is to create a ParseQuery, put conditions on it, and then retrieve a List of matching ParseObjects using the findInBackground method with a FindCallback. For example, to retrieve scores with a particular playerName, use the whereEqualTo method to constrain the value for a key:

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.whereEqualTo("playerName", "Dan Stemkoski");
query.findInBackground(new FindCallback<ParseObject>() {
    public void done(List<ParseObject> scoreList, ParseException e) {
        if (e == null) {
            Log.d("score", "Retrieved " + scoreList.size() + " scores");
        } else {
            Log.d("score", "Error: " + e.getMessage());
        }
    }
});

findInBackground works similarly to getInBackground in that it assures the network request is done on a background thread, and runs its callback in the main thread.

Query Constraints

There are several ways to put constraints on the objects found by a ParseQuery. You can filter out objects with a particular key-value pair with whereNotEqualTo:

query.whereNotEqualTo("playerName", "Michael Yabuti");

You can give multiple constraints, and objects will only be in the results if they match all of the constraints. In other words, it’s like an AND of constraints.

query.whereNotEqualTo("playerName", "Michael Yabuti");
query.whereGreaterThan("playerAge", 18);

You can limit the number of results with setLimit. By default, results are limited to 100. In the old Parse hosted backend, the maximum limit was 1,000, but Parse Server removed that constraint:

query.setLimit(10); // limit to at most 10 results

If you want exactly one result, a more convenient alternative may be to use getFirst or getFirstInBackground instead of using find.

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.whereEqualTo("playerEmail", "[email protected]");
query.getFirstInBackground(new GetCallback<ParseObject>() {
  public void done(ParseObject object, ParseException e) {
    if (object == null) {
      Log.d("score", "The getFirst request failed.");
    } else {
      Log.d("score", "Retrieved the object.");
    }
  }
});

You can skip the first results with setSkip. In the old Parse hosted backend, the maximum skip value was 10,000, but Parse Server removed that constraint. This can be useful for pagination:

query.setSkip(10); // skip the first 10 results

For sortable types like numbers and strings, you can control the order in which results are returned:

// Sorts the results in ascending order by the score field
query.orderByAscending("score");

// Sorts the results in descending order by the score field
query.orderByDescending("score");

You can add more sort keys to the query as follows:

// Sorts the results in ascending order by the score field if the previous sort keys are equal.
query.addAscendingOrder("score");

// Sorts the results in descending order by the score field if the previous sort keys are equal.
query.addDescendingOrder("score");

For sortable types, you can also use comparisons in queries:

// Restricts to wins < 50
query.whereLessThan("wins", 50);

// Restricts to wins <= 50
query.whereLessThanOrEqualTo("wins", 50);

// Restricts to wins > 50
query.whereGreaterThan("wins", 50);

// Restricts to wins >= 50
query.whereGreaterThanOrEqualTo("wins", 50);

If you want to retrieve objects matching several different values, you can use whereContainedIn, providing a collection of acceptable values. This is often useful to replace multiple queries with a single query. For example, if you want to retrieve scores made by any player in a particular list:

String[] names = {"Jonathan Walsh", "Dario Wunsch", "Shawn Simon"};
query.whereContainedIn("playerName", Arrays.asList(names));

If you want to retrieve objects that do not match any of several values you can use whereNotContainedIn, providing an array of acceptable values. For example, if you want to retrieve scores from players besides those in a list:

String[] names = {"Jonathan Walsh", "Dario Wunsch", "Shawn Simon"};
query.whereNotContainedIn("playerName", Arrays.asList(names));

If you want to retrieve objects that have a particular key set, you can use whereExists. Conversely, if you want to retrieve objects without a particular key set, you can use whereDoesNotExist.

// Finds objects that have the score set
query.whereExists("score");

// Finds objects that don't have the score set
query.whereDoesNotExist("score");

You can use the whereMatchesKeyInQuery method to get objects where a key matches the value of a key in a set of objects resulting from another query. For example, if you have a class containing sports teams and you store a user’s hometown in the user class, you can issue one query to find the list of users whose hometown teams have winning records. The query would look like:

ParseQuery<ParseObject> teamQuery = ParseQuery.getQuery("Team");
teamQuery.whereGreaterThan("winPct", 0.5);
ParseQuery<ParseUser> userQuery = ParseUser.getQuery();
userQuery.whereMatchesKeyInQuery("hometown", "city", teamQuery);
userQuery.findInBackground(new FindCallback<ParseUser>() {
  void done(List<ParseUser> results, ParseException e) {
    // results has the list of users with a hometown team with a winning record
  }
});

Conversely, to get objects where a key does not match the value of a key in a set of objects resulting from another query, use whereDoesNotMatchKeyInQuery. For example, to find users whose hometown teams have losing records:

ParseQuery<ParseUser> losingUserQuery = ParseUser.getQuery();
losingUserQuery.whereDoesNotMatchKeyInQuery("hometown", "city", teamQuery);
losingUserQuery.findInBackground(new FindCallback<ParseUser>() {
  void done(List<ParseUser> results, ParseException e) {
    // results has the list of users with a hometown team with a losing record
  }
});

To filter rows based on objectId’s from pointers in a second table, you can use dot notation:

ParseQuery<ParseObject> chartersOfTypeX = ParseQuery.getQuery("Charter");
charterOfTypeX.equalTo('type', 'x');

ParseQuery<ParseObject> groupsWithoutCharterX = ParseQuery.getQuery("Group");
groupsWithoutCharterX.doesNotMatchKeyInQuery("objectId", "belongsTo.objectId", chartersOfTypeX);
groupsWithoutCharterX.findInBackground(new FindCallback<ParseObject>() {
  void done(List<ParseObject> results, ParseException e) {
   // results has the list of groups without charter x
 });

You can restrict the fields returned by calling selectKeys with a collection of keys. To retrieve documents that contain only the score and playerName fields (and also special built-in fields such as objectId, createdAt, and updatedAt):

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.selectKeys(Arrays.asList("playerName", "score"));;
List<ParseObject> results = query.find();

The remaining fields can be fetched later by calling one of the fetchIfNeeded variants on the returned objects:

ParseObject object = results.get(0);
object.fetchIfNeededInBackground(new GetCallback<ParseObject>() {
  public void done(ParseObject object, ParseException e) {
    // all fields of the object will now be available here.
  }
});

Queries on Array Values

If a key contains an array value, you can search for objects where the key’s array value contains 2 by:

// Find objects where the array in arrayKey contains the number 2.
query.whereEqualTo("arrayKey", 2);

You can also search for objects where the key’s array value contains each of the values 2, 3, and 4 with the following:

// Find objects where the array in arrayKey contains all of the numbers 2, 3, and 4.
ArrayList<Integer> numbers = new ArrayList<Integer>();
numbers.add(2);
numbers.add(3);
numbers.add(4);
query.whereContainsAll("arrayKey", numbers);

Queries on String Values

Use whereStartsWith to restrict to string values that start with a particular string. Similar to a MySQL LIKE operator, this is indexed so it is efficient for large datasets:

// Finds barbecue sauces that start with 'Big Daddy's'.
ParseQuery<ParseObject> query = ParseQuery.getQuery("BarbecueSauce");
query.whereStartsWith("name", "Big Daddy's");

The above example will match any BarbecueSauce objects where the value in the “name” String key starts with “Big Daddy’s”. For example, both “Big Daddy’s” and “Big Daddy’s BBQ” will match, but “big daddy’s” or “BBQ Sauce: Big Daddy’s” will not.

Queries that have regular expression constraints are very expensive. Refer to the Performance Guide for more details.

Full Text Search

You can use whereFullText for efficient search capabilities. Text indexes are automatically created for you. Your strings are turned into tokens for fast searching.

• Note: Full Text Search can be resource intensive. Ensure the cost of using indexes is worth the benefit, see storage requirements & performance costs of text indexes..

• Requires Parse Server 2.5.0+

// Finds barbecue sauces that start with 'Big Daddy's'.
ParseQuery<ParseObject> query = ParseQuery.getQuery("BarbecueSauce");
query.whereFullText("name", "bbq");

The above example will match any BarbecueSauce objects where the value in the “name” String key contains “bbq”. For example, both “Big Daddy’s BBQ”, “Big Daddy’s bbq” and “Big BBQ Daddy” will match.

// You can sort by weight / rank. orderByAscending() and selectKeys()
ParseQuery<ParseObject> query = ParseQuery.getQuery("BarbecueSauce");
query.whereFullText("name", "Big Daddy's");
query.orderByAscending("$score");
query.selectKeys(Arrays.asList("$score"));
// results will contain $score, results[0].getInt("$score");
List<ParseObject> results = query.find();

For Case or Diacritic Sensitive search, please use the REST API.

Relational Queries

There are several ways to issue queries for relational data. If you want to retrieve objects where a field matches a particular ParseObject, you can use whereEqualTo just like for other data types. For example, if each Comment has a Post object in its post field, you can fetch comments for a particular Post:

// Assume ParseObject myPost was previously created.
ParseQuery<ParseObject> query = ParseQuery.getQuery("Comment");
query.whereEqualTo("post", myPost);

query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> commentList, ParseException e) {
    // commentList now has the comments for myPost
  }
});

If you want to retrieve objects where a field contains a ParseObject that matches a different query, you can use whereMatchesQuery. In order to find comments for posts containing images, you can do:

ParseQuery<ParseObject> innerQuery = ParseQuery.getQuery("Post");
innerQuery.whereExists("image");
ParseQuery<ParseObject> query = ParseQuery.getQuery("Comment");
query.whereMatchesQuery("post", innerQuery);
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> commentList, ParseException e) {
    // comments now contains the comments for posts with images.
  }
});

If you want to retrieve objects where a field contains a ParseObject that does not match a different query, you can use whereDoesNotMatchQuery. In order to find comments for posts without images, you can do:

ParseQuery<ParseObject> innerQuery = ParseQuery.getQuery("Post");
innerQuery.whereExists("image");
ParseQuery<ParseObject> query = ParseQuery.getQuery("Comment");
query.whereDoesNotMatchQuery("post", innerQuery);
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> commentList, ParseException e) {
    // comments now contains the comments for posts without images.
  }
});

In some situations, you want to return multiple types of related objects in one query. You can do this with the include method. For example, let’s say you are retrieving the last ten comments, and you want to retrieve their related posts at the same time:

ParseQuery<ParseObject> query = ParseQuery.getQuery("Comment");

// Retrieve the most recent ones
query.orderByDescending("createdAt");

// Only retrieve the last ten
query.setLimit(10);

// Include the post data with each comment
query.include("post");

query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> commentList, ParseException e) {
    // commentList now contains the last ten comments, and the "post"
    // field has been populated. For example:
    for (ParseObject comment : commentList) {
      // This does not require a network access.
      ParseObject post = comment.getParseObject("post");
      Log.d("post", "retrieved a related post");
    }
  }
});

You can also do multi level includes using dot notation. If you wanted to include the post for a comment and the post’s author as well you can do:

query.include("post.author");

You can issue a query with multiple fields included by calling include multiple times. This functionality also works with ParseQuery helpers like getFirst() and getInBackground().

Using the Local Datastore

If you have enabled the local datastore by calling Parse.enableLocalDatastore() before your call to Parse.initialize(), then you can also query against the objects stored locally on the device. To do this, call the fromLocalDatastore method on the query.

query.fromLocalDatastore();
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(final List<ParseObject> scoreList, ParseException e) {
    if (e == null) {
      // Results were successfully found from the local datastore.
    } else {
      // There was an error.
    }
  }
});

You can query from the local datastore using exactly the same kinds of queries you use over the network. The results will include every object that matches the query that’s been pinned to your device. The query even takes into account any changes you’ve made to the object that haven’t yet been saved to the cloud. For example, if you call deleteEventually, on an object, it will no longer be returned from these queries.

Caching Queries

With Local Datastore enabled

It’s often useful to cache the result of a query on a device. This lets you show data when the user’s device is offline, or when the app has just started and network requests have not yet had time to complete. The easiest way to do this is with the local datastore. When you pin objects, you can attach a label to the pin, which lets you manage a group of objects together. For example, to cache the results of the query above, you can call pinAllInBackground and give it a label.

final String TOP_SCORES_LABEL = "topScores";

// Query for the latest objects from Parse.
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(final List<ParseObject> scoreList, ParseException e) {
    if (e != null) {
      // There was an error or the network wasn't available.
      return;
    }

    // Release any objects previously pinned for this query.
    ParseObject.unpinAllInBackground(TOP_SCORES_LABEL, scoreList, new DeleteCallback() {
      public void done(ParseException e) {
        if (e != null) {
          // There was some error.
          return;
        }

        // Add the latest results for this query to the cache.
        ParseObject.pinAllInBackground(TOP_SCORES_LABEL, scoreList);
      }
    });
  }
});

Now when you do any query with fromLocalDatastore, these objects will be included in the results if they still match the query. ParseQuery lets you choose whether to query the network (fromNetwork) or the local datastore (fromLocalDatastore or fromPin(label) to query just a subset). It is also possible to chain both requests, or execute them in parallel.

For instance, to query the cache first and then the network,

final ParseQuery query = ParseQuery.getQuery("GameScore");
query.fromLocalDatastore().findInBackground().continueWithTask((task) -> {
  // Update UI with results from Local Datastore ...
  ParseException error = task.getError();
  if(error == null){
    List<ParseObject> gameScore = task.getResult();
    for(ParseObject game : gameScore){
        //...
    }
  }
  // Now query the network:
  return query.fromNetwork().findInBackground();
}, Task.UI_EXECUTOR).continueWithTask((task) -> {
  // Update UI with results from Network ...
  ParseException error = task.getError();
  if(error == null){
    List<ParseObject> gameScore = task.getResult();
    for(ParseObject game : gameScore){
        //...
    }
  }
  return task;
}, Task.UI_EXECUTOR);

Or you might want to query the cache, and if that fails, fire a network call:

final ParseQuery query = ParseQuery.getQuery("GameScore");
query.fromLocalDatastore().findInBackground().continueWithTask((task) -> {
  Exception error = task.getError();
  if (error instanceof ParseException && ((ParseException) error).getCode() == ParseException.CACHE_MISS) {
    // No results from cache. Let's query the network.
    ParseException error = task.getError();
    if(error == null){
      List<ParseObject> gameScore = task.getResult();
      for(ParseObject game : gameScore){
          //...
      }
    }
    return query.fromNetwork().findInBackground();
  }
  return task;
}).continueWithTask((task) -> {
  // Update UI with results ...
  return task;
}, Task.UI_EXECUTOR);

Without Local Datastore

If you aren’t using the local datastore, you can use the per-query cache for ParseQuery instead. The default query behavior doesn’t use the cache, but you can enable caching with setCachePolicy. For example, to try the network and then fall back to cached data if the network is not available:

query.setCachePolicy(ParseQuery.CachePolicy.NETWORK_ELSE_CACHE);
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> scoreList, ParseException e) {
    if (e == null) {
      // Results were successfully found, looking first on the
      // network and then on disk.
    } else {
      // The network was inaccessible and we have no cached data
      // for this query.
    }
  }
});

Parse provides several different cache policies:

• IGNORE_CACHE: The query does not load from the cache or save results to the cache. IGNORE_CACHE is the default cache policy.
• CACHE_ONLY: The query only loads from the cache, ignoring the network. If there are no cached results, that causes a ParseException.
• NETWORK_ONLY: The query does not load from the cache, but it will save results to the cache.
• CACHE_ELSE_NETWORK: The query first tries to load from the cache, but if that fails, it loads results from the network. If neither cache nor network succeed, there is a ParseException.
• NETWORK_ELSE_CACHE: The query first tries to load from the network, but if that fails, it loads results from the cache. If neither network nor cache succeed, there is a ParseException.
• CACHE_THEN_NETWORK: The query first loads from the cache, then loads from the network. In this case, the FindCallback will actually be called twice - first with the cached results, then with the network results. This cache policy can only be used asynchronously with findInBackground.

If you need to control the cache’s behavior, you can use methods provided in ParseQuery to interact with the cache. You can do the following operations on the cache:

• Check to see if there is a cached result for the query with:

  boolean isInCache = query.hasCachedResult();
  

• Remove any cached results for a query with:

  query.clearCachedResult();
  

• Remove cached results for all queries with:

  ParseQuery.clearAllCachedResults();
  

Query caching also works with ParseQuery helpers including getFirst() and getInBackground().

Counting Objects

Note: In the old Parse hosted backend, count queries were rate limited to a maximum of 160 requests per minute. They also returned inaccurate results for classes with more than 1,000 objects. But, Parse Server has removed both constraints and can count objects well above 1,000.

If you just need to count how many objects match a query, but you do not need to retrieve all the objects that match, you can use count instead of find. For example, to count how many games have been played by a particular player:

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.whereEqualTo("playerName", "Sean Plott");
query.countInBackground(new CountCallback() {
  public void done(int count, ParseException e) {
    if (e == null) {
      // The count request succeeded. Log the count
      Log.d("score", "Sean has played " + count + " games");
    } else {
      // The request failed
    }
  }
});

If you want to block the calling thread, you can also use the synchronous query.count() method.

Compound Queries

If you want to find objects that match one of several queries, you can use ParseQuery.or method to construct a query that is an or of the queries passed in. For instance if you want to find players who either have a lot of wins or a few wins, you can do:

ParseQuery<ParseObject> lotsOfWins = ParseQuery.getQuery("Player");
lotsOfWins.whereGreaterThan(150);

ParseQuery<ParseObject> fewWins = ParseQuery.getQuery("Player");
fewWins.whereLessThan(5);

List<ParseQuery<ParseObject>> queries = new ArrayList<ParseQuery<ParseObject>>();
queries.add(lotsOfWins);
queries.add(fewWins);

ParseQuery<ParseObject> mainQuery = ParseQuery.or(queries);
mainQuery.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> results, ParseException e) {
    // results has the list of players that win a lot or haven't won much.
  }
});

You can add additional constraints to the newly created ParseQuery that act as an ‘and’ operator.

Note that we do not, however, support GeoPoint or non-filtering constraints (e.g. whereNear, withinGeoBox, setLimit, skip, orderBy..., include) in the subqueries of the compound query.

Users

At the core of many apps, there is a notion of user accounts that lets users access their information in a secure manner. We provide a specialized user class called ParseUser that automatically handles much of the functionality required for user account management.

With this class, you’ll be able to add user account functionality in your app.

ParseUser is a subclass of the ParseObject, and has all the same features, such as flexible schema, automatic persistence, and a key value interface. All the methods that are on ParseObject also exist in ParseUser. The difference is that ParseUser has some special additions specific to user accounts.

ParseUser Properties

ParseUser has several properties that set it apart from ParseObject:

• username: The username for the user (required).
• password: The password for the user (required on signup).
• email: The email address for the user (optional).

We’ll go through each of these in detail as we run through the various use cases for users. Keep in mind that if you set username and email using the setters, you do not need to set it using the put method.

Signing Up

The first thing your app will do is probably ask the user to sign up. The following code illustrates a typical sign up:

ParseUser user = new ParseUser();
user.setUsername("my name");
user.setPassword("my pass");
user.setEmail("[email protected]");

// other fields can be set just like with ParseObject
user.put("phone", "650-253-0000");

user.signUpInBackground(new SignUpCallback() {
  public void done(ParseException e) {
    if (e == null) {
      // Hooray! Let them use the app now.
    } else {
      // Sign up didn't succeed. Look at the ParseException
      // to figure out what went wrong
    }
  }
});

This call will asynchronously create a new user in your Parse App. Before it does this, it checks to make sure that both the username and email are unique. Also, it securely hashes the password in the cloud using bcrypt. We never store passwords in plaintext, nor will we ever transmit passwords back to the client in plaintext.

Note that we used the signUpInBackground method, not the saveInBackground method. New ParseUsers should always be created using the signUpInBackground (or signUp) method. Subsequent updates to a user can be done by calling save.

The signUpInBackground method comes in various flavors, with the ability to pass back errors, and also synchronous versions. As usual, we highly recommend using the asynchronous versions when possible, so as not to block the UI in your app. You can read more about these specific methods in our API docs.

If a signup isn’t successful, you should read the error object that is returned. The most likely case is that the username or email has already been taken by another user. You should clearly communicate this to your users, and ask them try a different username.

You are free to use an email address as the username. Simply ask your users to enter their email, but fill it in the username property — ParseUser will work as normal. We’ll go over how this is handled in the reset password section.

Logging In

Of course, after you allow users to sign up, you need be able to let them log in to their account in the future. To do this, you can use the class method logInInBackground.

ParseUser.logInInBackground("Jerry", "showmethemoney", new LogInCallback() {
  public void done(ParseUser user, ParseException e) {
    if (user != null) {
      // Hooray! The user is logged in.
    } else {
      // Signup failed. Look at the ParseException to see what happened.
    }
  }
});

Verifying Emails

Enabling email verification in an application’s settings allows the application to reserve part of its experience for users with confirmed email addresses. Email verification adds the emailVerified key to the ParseUser object. When a ParseUser’s email is set or modified, emailVerified is set to false. Parse then emails the user a link which will set emailVerified to true.

There are three emailVerified states to consider:

1. true - the user confirmed his or her email address by clicking on the link Parse emailed them. ParseUsers can never have a true value when the user account is first created.
2. false - at the time the ParseUser object was last fetched, the user had not confirmed his or her email address. If emailVerified is false, consider calling fetch() on the ParseUser.
3. missing - the ParseUser was created when email verification was off or the ParseUser does not have an email.

Current User

It would be bothersome if the user had to log in every time they open your app. You can avoid this by using the cached currentUser object.

Whenever you use any signup or login methods, the user is cached on disk. You can treat this cache as a session, and automatically assume the user is logged in:

ParseUser currentUser = ParseUser.getCurrentUser();
if (currentUser != null) {
  // do stuff with the user
} else {
  // show the signup or login screen
}

You can clear the current user by logging them out:

ParseUser.logOut();
ParseUser currentUser = ParseUser.getCurrentUser(); // this will now be null

Anonymous Users

Being able to associate data and objects with individual users is highly valuable, but sometimes you want to be able to do this without forcing a user to specify a username and password.

An anonymous user is a user that can be created without a username and password but still has all of the same capabilities as any other ParseUser. After logging out, an anonymous user is abandoned, and its data is no longer accessible.

You can create an anonymous user using ParseAnonymousUtils:

ParseAnonymousUtils.logIn(new LogInCallback() {
  @Override
  public void done(ParseUser user, ParseException e) {
    if (e != null) {
      Log.d("MyApp", "Anonymous login failed.");
    } else {
      Log.d("MyApp", "Anonymous user logged in.");
    }
  }
});

You can convert an anonymous user into a regular user by setting the username and password, then calling signUp(), or by logging in or linking with a service like Facebook or Twitter. The converted user will retain all of its data. To determine whether the current user is an anonymous user, you can check ParseAnonymousUtils.isLinked():

if (ParseAnonymousUtils.isLinked(ParseUser.getCurrentUser())) {
  enableSignUpButton();
} else {
  enableLogOutButton();
}

Anonymous users can also be automatically created for you without requiring a network request, so that you can begin working with your user immediately when your application starts. When you enable automatic anonymous user creation at application startup, ParseUser.getCurrentUser() will never be null. The user will automatically be created in the cloud the first time the user or any object with a relation to the user is saved. Until that point, the user’s object ID will be null. Enabling automatic user creation makes associating data with your users painless. For example, in your Application.onCreate() method, you might write:

ParseUser.enableAutomaticUser();
ParseUser.getCurrentUser().increment("RunCount");
ParseUser.getCurrentUser().saveInBackground();

Setting the Current User

If you’ve created your own authentication routines, or otherwise logged in a user on the server side, you can now pass the session token to the client and use the become method. This method will ensure the session token is valid before setting the current user.

ParseUser.becomeInBackground("session-token-here", new LogInCallback() {
  public void done(ParseUser user, ParseException e) {
    if (user != null) {
      // The current user is now set to user.
    } else {
      // The token could not be validated.
    }
  }
});

Security For User Objects

The ParseUser class is secured by default. Data stored in a ParseUser can only be modified by that user. By default, the data can still be read by any client. Thus, some ParseUser objects are authenticated and can be modified, whereas others are read-only.

Specifically, you are not able to invoke any of the save or delete type methods unless the ParseUser was obtained using an authenticated method, like logIn or signUp. This ensures that only the user can alter their own data.

The following illustrates this security policy:

ParseUser user = ParseUser.logIn("my_username", "my_password");
user.setUsername("my_new_username"); // attempt to change username
user.saveInBackground(); // This succeeds, since the user was authenticated on the device

// Get the user from a non-authenticated manner
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.getInBackground(user.getObjectId(), new GetCallback<ParseUser>() {
  public void done(ParseUser object, ParseException e) {
    object.setUsername("another_username");

    // This will throw an exception, since the ParseUser is not authenticated
    object.saveInBackground();
  }
});

The ParseUser obtained from getCurrentUser() will always be authenticated.

If you need to check if a ParseUser is authenticated, you can invoke the isAuthenticated() method. You do not need to check isAuthenticated() with ParseUser objects that are obtained via an authenticated method.

Security for Other Objects

The same security model that applies to the ParseUser can be applied to other objects. For any object, you can specify which users are allowed to read the object, and which users are allowed to modify an object. To support this type of security, each object has an access control list, implemented by the ParseACL class.

The simplest way to use a ParseACL is to specify that an object may only be read or written by a single user. To create such an object, there must first be a logged in ParseUser. Then, new ParseACL(user) generates a ParseACL that limits access to that user. An object’s ACL is updated when the object is saved, like any other property. Thus, to create a private note that can only be accessed by the current user:

ParseObject privateNote = new ParseObject("Note");
privateNote.put("content", "This note is private!");
privateNote.setACL(new ParseACL(ParseUser.getCurrentUser()));
privateNote.saveInBackground();

This note will then only be accessible to the current user, although it will be accessible to any device where that user is signed in. This functionality is useful for applications where you want to enable access to user data across multiple devices, like a personal todo list.

Permissions can also be granted on a per-user basis. You can add permissions individually to a ParseACL using setReadAccess and setWriteAccess. For example, let’s say you have a message that will be sent to a group of several users, where each of them have the rights to read and delete that message:

ParseObject groupMessage = new ParseObject("Message");
ParseACL groupACL = new ParseACL();

// userList is an Iterable<ParseUser> with the users we are sending this message to.
for (ParseUser user : userList) {
  groupACL.setReadAccess(user, true);
  groupACL.setWriteAccess(user, true);
}

groupMessage.setACL(groupACL);
groupMessage.saveInBackground();

You can also grant permissions to all users at once using setPublicReadAccess and setPublicWriteAccess. This allows patterns like posting comments on a message board. For example, to create a post that can only be edited by its author, but can be read by anyone:

ParseObject publicPost = new ParseObject("Post");
ParseACL postACL = new ParseACL(ParseUser.getCurrentUser());
postACL.setPublicReadAccess(true);
publicPost.setACL(postACL);
publicPost.saveInBackground();

To help ensure that your users’ data is secure by default, you can set a default ACL to be applied to all newly-created ParseObjects:

ParseACL.setDefaultACL(defaultACL, true);

In the code above, the second parameter to setDefaultACL tells Parse to ensure that the default ACL assigned at the time of object creation allows read and write access to the current user at that time. Without this setting, you would need to reset the defaultACL every time a user logs in or out so that the current user would be granted access appropriately. With this setting, you can ignore changes to the current user until you explicitly need to grant different kinds of access.

Default ACLs make it easy to create apps that follow common access patterns. An application like Twitter, for example, where user content is generally visible to the world, might set a default ACL such as:

ParseACL defaultACL = new ParseACL();
defaultACL.setPublicReadAccess(true);
ParseACL.setDefaultACL(defaultACL, true);

For an application like Dropbox, where a user’s data is only accessible by the user itself unless explicit permission is given, you would provide a default ACL where only the current user is given access:

ParseACL.setDefaultACL(new ParseACL(), true);

An application that logs data to Parse but doesn’t provide any user access to that data would instead deny access to the current user while providing a restrictive ACL:

ParseACL.setDefaultACL(new ParseACL(), false);

Operations that are forbidden, such as deleting an object that you do not have write access to, result in a ParseException.OBJECT_NOT_FOUND error code. For security purposes, this prevents clients from distinguishing which object ids exist but are secured, versus which object ids do not exist at all.

Resetting Passwords

It’s a fact that as soon as you introduce passwords into a system, users will forget them. In such cases, our library provides a way to let them securely reset their password.

To kick off the password reset flow, ask the user for their email address, and call:

ParseUser.requestPasswordResetInBackground("[email protected]", new RequestPasswordResetCallback() {
  public void done(ParseException e) {
    if (e == null) {
      // An email was successfully sent with reset instructions.
    } else {
      // Something went wrong. Look at the ParseException to see what's up.
    }
  }
});

This will attempt to match the given email with the user’s email or username field, and will send them a password reset email. By doing this, you can opt to have users use their email as their username, or you can collect it separately and store it in the email field.

The flow for password reset is as follows:

1. User requests that their password be reset by typing in their email.
2. Parse sends an email to their address, with a special password reset link.
3. User clicks on the reset link, and is directed to a special Parse page that will allow them type in a new password.
4. User types in a new password. Their password has now been reset to a value they specify.

Note that the messaging in this flow will reference your app by the name that you specified when you created this app on Parse.

Querying

To query for users, you need to use the special user query:

ParseQuery<ParseUser> query = ParseUser.getQuery();
query.whereEqualTo("gender", "female");
query.findInBackground(new FindCallback<ParseUser>() {
  public void done(List<ParseUser> objects, ParseException e) {
    if (e == null) {
        // The query was successful.
    } else {
        // Something went wrong.
    }
  }
});

In addition, you can use get to get a ParseUser by id.

Associations

Associations involving a ParseUser work right of the box. For example, let’s say you’re making a blogging app. To store a new post for a user and retrieve all their posts:

ParseUser user = ParseUser.getCurrentUser();

// Make a new post
ParseObject post = new ParseObject("Post");
post.put("title", "My New Post");
post.put("body", "This is some great content.");
post.put("user", user);
post.saveInBackground();

// Find all posts by the current user
ParseQuery<ParseObject> query = ParseQuery.getQuery("Post");
query.whereEqualTo("user", user);
query.findInBackground(new FindCallback<ParseObject>() { ... });

Facebook Users

Parse provides an easy way to integrate Facebook with your application. The Facebook SDK can be used with our SDK, and is integrated with the ParseUser class to make linking your users to their Facebook identities easy.

Using our Facebook integration, you can associate an authenticated Facebook user with a ParseUser. With just a few lines of code, you’ll be able to provide a “Log in with Facebook” option in your app, and be able to save their data to Parse.

Note: Parse is compatible with both Facebook SDK 3.x and 4.x for Android. These instructions are for Facebook SDK 4.x.

Setting up Facebook

To start using Facebook with Parse, you need to:

1. Set up a Facebook app, if you haven’t already.
2. Add your application’s Facebook Application ID on your Parse application’s settings page.
3. Follow Facebook’s instructions for getting started with the Facebook SDK to create an app linked to the Facebook SDK. Once you get to Step 6, stop after linking the Facebook SDK project and configuring the Facebook app ID. You can use our guide to attach your Parse users to Facebook accounts when logging in.
4. Add 'com.github.parse-community:ParseFacebookUtils-Android:latest.version.here' to your Gradle dependencies (X.X.X should be )
5. Add the following where you initialize the Parse SDK in your Application.onCreate():

  ParseFacebookUtils.initialize(context);

Facebook’s Android SDK provides an enhanced login experience on devices that have Facebook’s official Android app installed. This allows users of apps that support Facebook login to sign in directly through the Facebook app, using credentials that are already on the device. If the Facebook app is not installed, the default dialog-based authentication will be used. Facebook calls this feature “Single sign-on” (SSO), and requires you to override onActivityResult() in your calling Activity:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  ParseFacebookUtils.onActivityResult(requestCode, resultCode, data);
}

If your Activity is already using onActivityResult(), you can avoid requestCode collisions by specifying your own request code offset when initializing ParseFacebookUtils.initialize(context, callbackRequestCodeOffset). Otherwise, a sensible default activityCode will be used.

If you encounter any issues that are Facebook-related, a good resource is the official Facebook SDK for Android page.

There are two main ways to use Facebook with your Parse users: (1) logging in as a Facebook user and creating a ParseUser, or (2) linking Facebook to an existing ParseUser.

Login & Signup

ParseFacebookUtils provides a way to allow your ParseUsers to log in or sign up through Facebook. This is generally accomplished using the logInWithReadPermissionsInBackground(String, Collection<String>) method:

ParseFacebookUtils.logInWithReadPermissionsInBackground(this, permissions, new LogInCallback() {
  @Override
  public void done(ParseUser user, ParseException err) {
    if (user == null) {
      Log.d("MyApp", "Uh oh. The user cancelled the Facebook login.");
    } else if (user.isNew()) {
      Log.d("MyApp", "User signed up and logged in through Facebook!");
    } else {
      Log.d("MyApp", "User logged in through Facebook!");
    }
  }
});

When this code is run, the following happens:

1. The user is shown the Facebook login dialog or a prompt generated by the Facebook app.
2. The user authenticates via Facebook, and your app receives a callback.
3. Our SDK receives the user’s Facebook access data and saves it to a ParseUser. If no ParseUser exists with the same Facebook ID, then a new ParseUser is created.
4. Your LogInCallback is called with the user.
5. The current user reference will be updated to this user.

In order to display the Facebook login dialogs and activities, the current Activity must be provided (often, the current activity is this when calling logInWithReadPermissionsInBackground() from within the Activity) as we have done above.

ParseUser integration doesn’t require any permissions to work out of the box (i.e. null is perfectly acceptable). When logging in, you can only use read permissions. See our documentation below about requesting additional permissions (read or publish). Read more about permissions on Facebook’s developer guide.

Facebook Linking

If you want to associate an existing ParseUser to a Facebook account, you can link it like so:

if (!ParseFacebookUtils.isLinked(user)) {
  ParseFacebookUtils.linkWithReadPermissionsInBackground(user, this, permissions, new SaveCallback() {
    @Override
    public void done(ParseException ex) {
      if (ParseFacebookUtils.isLinked(user)) {
        Log.d("MyApp", "Woohoo, user logged in with Facebook!");
      }
    }
  });
}

The steps that happen when linking are very similar to log in. The difference is that on successful login, the existing ParseUser is updated with the Facebook information. Future logins via Facebook will now log the user into their existing account.

If you want to unlink Facebook from a user, simply do this:

ParseFacebookUtils.unlinkInBackground(user, new SaveCallback() {
  @Override
  public void done(ParseException ex) {
    if (ex == null) {
      Log.d("MyApp", "The user is no longer associated with their Facebook account.");
    }
  }
});

Requesting Permissions

As of v3.0 of the Facebook SDK, read and publish permissions must be requested separately. To request additional permissions, you may call ParseFacebookUtils.linkWithReadPermissionsInBackground() or ParseFacebookUtils.linkWithPublishPermissionsInBackground(). For more information about requesting new permissions, please see Facebook’s API documentation for these functions.

After successfully retrieving new permissions, please call ParseFacebookUtilities.linkInBackground(ParseUser, AccessToken), which will save any changes to the session token back to the ParseUser and ensure that this session data follows the user wherever it logs in.

Facebook SDK and Parse

The Facebook Android SDK provides a number of helper classes for interacting with Facebook’s API. Generally, you will use the GraphRequest class to interact with Facebook on behalf of your logged-in user. You can read more about the Facebook SDK here.

To access the user’s AccessToken you can simply call AccessToken.getCurrentAccessToken() to access the AccessToken instance, which can then be passed to GraphRequests.

Twitter Users

As with Facebook, Parse also provides an easy way to integrate Twitter authentication into your application. The Parse SDK provides a straightforward way to authorize and link a Twitter account to your ParseUsers. With just a few lines of code, you’ll be able to provide a “log in with Twitter” option in your app, and be able to save their data to Parse.

Setting up Twitter

To start using Twitter with Parse, you need to:

1. Set up a Twitter app, if you haven’t already.
2. Add your application’s Twitter consumer key on your Parse application’s settings page.
3. When asked to specify a “Callback URL” for your Twitter app, please insert twittersdk://. This is necessary in order to enable authentication through Twitter.
4. Add 'com.github.parse-community:ParseTwitterUtils-Android:latest.version.here' to your Gradle dependencies.
5. Add the following where you initialize the Parse SDK in your Application.onCreate()

ParseTwitterUtils.initialize("YOUR CONSUMER KEY", "YOUR CONSUMER SECRET");

If you encounter any issues that are Twitter-related, a good resource is the official Twitter documentation.

There are two main ways to use Twitter with your Parse users: (1) logging in as a Twitter user and creating a ParseUser, or (2) linking Twitter to an existing ParseUser.

Login & Signup

ParseTwitterUtils provides a way to allow your ParseUsers to log in or sign up through Twitter. This is accomplished using the logIn() method:

ParseTwitterUtils.logIn(this, new LogInCallback() {
  @Override
  public void done(ParseUser user, ParseException err) {
    if (user == null) {
      Log.d("MyApp", "Uh oh. The user cancelled the Twitter login.");
    } else if (user.isNew()) {
      Log.d("MyApp", "User signed up and logged in through Twitter!");
    } else {
      Log.d("MyApp", "User logged in through Twitter!");
    }
  }
});

When this code is run, the following happens:

1. The user is shown the Twitter login dialog.
2. The user authenticates via Twitter, and your app receives a callback.
3. Our SDK receives the Twitter data and saves it to a ParseUser. If it’s a new user based on the Twitter handle, then that user is created.
4. Your LogInCallback is called with the user.

In order to display the Twitter login dialogs and activities, the current Context must be provided (often, the current context is this when calling logIn() from within the Activity) as we have done above.

Twitter Linking

If you want to associate an existing ParseUser with a Twitter account, you can link it like so:

if (!ParseTwitterUtils.isLinked(user)) {
  ParseTwitterUtils.link(user, this, new SaveCallback() {
    @Override
    public void done(ParseException ex) {
      if (ParseTwitterUtils.isLinked(user)) {
        Log.d("MyApp", "Woohoo, user logged in with Twitter!");
      }
    }
  });
}

The steps that happen when linking are very similar to log in. The difference is that on successful login, the existing ParseUser is updated with the Twitter information. Future logins via Twitter will now log the user into their existing account.

If you want to unlink Twitter from a user, simply do this:

ParseTwitterUtils.unlinkInBackground(user, new SaveCallback() {
  @Override
  public void done(ParseException ex) {
    if (ex == null) {
      Log.d("MyApp", "The user is no longer associated with their Twitter account.");
    }
  }
});

Twitter API Calls

Our SDK provides a straightforward way to sign your API HTTP requests to the Twitter REST API when your app has a Twitter-linked ParseUser. To make a request using OkHttp, you can use the Twitter singleton provided by ParseTwitterUtils:

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
      .url("https://api.twitter.com/1.1/account/verify_credentials.json")
      .build();

OkHttpOAuthConsumer consumer = new OkHttpOAuthConsumer(Twitter.getConsumerKey(), Twitter.getConsumerSecret());
Request signedRequest = (Request) consumer.sign(request).unwrap();
// or enqueue
Response response = client.newCall(signedRequest).execute();

Sessions

Sessions represent an instance of a user logged into a device. Sessions are automatically created when users log in or sign up. They are automatically deleted when users log out. There is one distinct Session object for each user-installation pair; if a user issues a login request from a device they’re already logged into, that user’s previous Session object for that Installation is automatically deleted. Session objects are stored on Parse in the Session class, and you can view them on the Parse Dashboard Data Browser. We provide a set of APIs to manage Session objects in your app.

Session is a subclass of a Parse Object, so you can query, update, and delete sessions in the same way that you manipulate normal objects on Parse. Because Parse Server automatically creates sessions when you log in or sign up users, you should not manually create Session objects unless you are building an IoT app (e.g. Arduino or Embedded C). Deleting a Session will log the user out of the device that is currently using this session’s token.

Unlike other Parse objects, the Session class does not have Cloud Code triggers. So you cannot register a beforeSave or afterSave handler for the Session class.

Session Properties

The Session object has these special fields:

• sessionToken (readonly): String token for authentication on Parse API requests. In the response of Session queries, only your current Session object will contain a session token.
• user: (readonly) Pointer to the User object that this session is for.
• createdWith (readonly): Information about how this session was created (e.g. { "action": "login", "authProvider": "password"}).
  • action could have values: login, signup, create, or upgrade. The create action is when the developer manually creates the session by saving a Session object. The upgrade action is when the user is upgraded to revocable session from a legacy session token.
  • authProvider could have values: password, anonymous, facebook, or twitter.
• expiresAt (readonly): Approximate UTC date when this Session object will be automatically deleted. You can configure session expiration settings (either 1-year inactivity expiration or no expiration) in your app’s Parse Dashboard settings page.
• installationId (can be set only once): String referring to the Installation where the session is logged in from. For Parse SDKs, this field will be automatically set when users log in or sign up. All special fields except installationId can only be set automatically by Parse Server. You can add custom fields onto Session objects, but please keep in mind that any logged-in device (with session token) can read other sessions that belong to the same user (unless you disable Class-Level Permissions, see below).

Handling Invalid Session Token Error

With revocable sessions, your current session token could become invalid if its corresponding Session object is deleted from your Parse Server. This could happen if you implement a Session Manager UI that lets users log out of other devices, or if you manually delete the session via Cloud Code, REST API, or Data Browser. Sessions could also be deleted due to automatic expiration (if configured in app settings). When a device’s session token no longer corresponds to a Session object on your Parse Server, all API requests from that device will fail with “Error 209: invalid session token”.

To handle this error, we recommend writing a global utility function that is called by all of your Parse request error callbacks. You can then handle the “invalid session token” error in this global function. You should prompt the user to login again so that they can obtain a new session token. This code could look like this:

public class ParseErrorHandler {
  public static void handleParseError(ParseException e) {
    switch (e.getCode()) {
      case INVALID_SESSION_TOKEN: handleInvalidSessionToken()
        break;

      ... // Other Parse API errors that you want to explicitly handle
    }
  }

  private static void handleInvalidSessionToken() {
    //--------------------------------------
    // Option 1: Show a message asking the user to log out and log back in.
    //--------------------------------------
    // If the user needs to finish what they were doing, they have the opportunity to do so.
    //
    // new AlertDialog.Builder(getActivity())
    //   .setMessage("Session is no longer valid, please log out and log in again.")
    //   .setCancelable(false).setPositiveButton("OK", ...).create().show();

    //--------------------------------------
    // Option #2: Show login screen so user can re-authenticate.
    //--------------------------------------
    // You may want this if the logout button could be inaccessible in the UI.
    //
    // startActivityForResult(new ParseLoginBuilder(getActivity()).build(), 0);
  }
}

// In all API requests, call the global error handler, e.g.
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> results, ParseException e) {
    if (e == null) {
      // Query successful, continue other app logic
    } else {
      // Query failed
      ParseErrorHandler.handleParseError(e);
    }
  }
});

Session Security

Session objects can only be accessed by the user specified in the user field. All Session objects have an ACL that is read and write by that user only. You cannot change this ACL. This means querying for sessions will only return objects that match the current logged-in user.

When you log in a user via a User login method, Parse will automatically create a new unrestricted Session object in your Parse Server. Same for signups and Facebook/Twitter logins.

You can configure Class-Level Permissions (CLPs) for the Session class just like other classes on Parse. CLPs restrict reading/writing of sessions via the Session API, but do not restrict Parse Server’s automatic session creation/deletion when users log in, sign up, and log out. We recommend that you disable all CLPs not needed by your app. Here are some common use cases for Session CLPs:

• Find, Delete — Useful for building a UI screen that allows users to see their active session on all devices, and log out of sessions on other devices. If your app does not have this feature, you should disable these permissions.
• Create — Useful for apps that provision user sessions for other devices from the phone app. You should disable this permission when building apps for mobile and web. For IoT apps, you should check whether your IoT device actually needs to access user-specific data. If not, then your IoT device does not need a user session, and you should disable this permission.
• Get, Update, Add Field — Unless you need these operations, you should disable these permissions.

Roles

As your app grows in scope and user-base, you may find yourself needing more coarse-grained control over access to pieces of your data than user-linked ACLs can provide. To address this requirement, Parse supports a form of Role-based Access Control. Roles provide a logical way of grouping users with common access privileges to your Parse data. Roles are named objects that contain users and other roles. Any permission granted to a role is implicitly granted to its users as well as to the users of any roles that it contains.

For example, in your application with curated content, you may have a number of users that are considered “Moderators” and can modify and delete content created by other users. You may also have a set of users that are “Administrators” and are allowed all of the same privileges as Moderators, but can also modify the global settings for the application. By adding users to these roles, you can ensure that new users can be made moderators or administrators, without having to manually grant permission to every resource for each user.

We provide a specialized class called ParseRole that represents these role objects in your client code. ParseRole is a subclass of ParseObject, and has all of the same features, such as a flexible schema, automatic persistence, and a key value interface. All the methods that are on ParseObject also exist on ParseRole. The difference is that ParseRole has some additions specific to management of roles.

ParseRole Properties

ParseRole has several properties that set it apart from ParseObject:

• name: The name for the role. This value is required, and can only be set once as a role is being created. The name must consist of alphanumeric characters, spaces, -, or _. This name will be used to identify the Role without needing its objectId.
• users: A relation to the set of users that will inherit permissions granted to the containing role.
• roles: A relation to the set of roles whose users and roles will inherit permissions granted to the containing role.

Security for Role Objects

The ParseRole uses the same security scheme (ACLs) as all other objects on Parse, except that it requires an ACL to be set explicitly. Generally, only users with greatly elevated privileges (e.g. a master user or Administrator) should be able to create or modify a Role, so you should define its ACLs accordingly. Remember, if you give write-access to a ParseRole to a user, that user can add other users to the role, or even delete the role altogether.

To create a new ParseRole, you would write:

// By specifying no write privileges for the ACL, we can ensure the role cannot be altered.
ParseACL roleACL = new ParseACL();
roleACL.setPublicReadAccess(true);
ParseRole role = new ParseRole("Administrator", roleACL);
role.saveInBackground();

You can add users and roles that should inherit your new role’s permissions through the “users” and “roles” relations on ParseRole:

ParseRole role = new ParseRole(roleName, roleACL);
for (ParseUser user : usersToAddToRole) {
  role.getUsers().add(user)
}
for (ParseRole childRole : rolesToAddToRole) {
  role.getRoles().add(childRole);
}
role.saveInBackground();

Take great care when assigning ACLs to your roles so that they can only be modified by those who should have permissions to modify them.

Role Based Security for Other Objects

Now that you have created a set of roles for use in your application, you can use them with ACLs to define the privileges that their users will receive. Each ParseObject can specify a ParseACL, which provides an access control list that indicates which users and roles should be granted read or write access to the object.

Giving a role read or write permission to an object is straightforward. You can either use the ParseRole:

ParseRole moderators = /* Query for some ParseRole */;
ParseObject wallPost = new ParseObject("WallPost");
ParseACL postACL = new ParseACL();
postACL.setRoleWriteAccess(moderators);
wallPost.setACL(postACL);
wallPost.saveInBackground();

You can avoid querying for a role by specifying its name for the ACL:

ParseObject wallPost = new ParseObject("WallPost");
ParseACL postACL = new ParseACL();
postACL.setRoleWriteAccess("Moderators", true);
wallPost.setACL(postACL);
wallPost.save();

Role-based ParseACLs can also be used when specifying default ACLs for your application, making it easy to protect your users’ data while granting access to users with additional privileges. For example, a moderated forum application might specify a default ACL like this:

ParseACL defaultACL = new ParseACL();
// Everybody can read objects created by this user
defaultACL.setPublicReadAccess(true);
// Moderators can also modify these objects
defaultACL.setRoleWriteAccess("Moderators");
// And the user can read and modify its own objects
ParseACL.setDefaultACL(defaultACL, true);

Role Hierarchy

As described above, one role can contain another, establishing a parent-child relationship between the two roles. The consequence of this relationship is that any permission granted to the parent role is implicitly granted to all of its child roles.

These types of relationships are commonly found in applications with user-managed content, such as forums. Some small subset of users are “Administrators”, with the highest level of access to tweaking the application’s settings, creating new forums, setting global messages, and so on. Another set of users are “Moderators”, who are responsible for ensuring that the content created by users remains appropriate. Any user with Administrator privileges should also be granted the permissions of any Moderator. To establish this relationship, you would make your “Administrators” role a child role of “Moderators”, like this:

ParseRole administrators = /* Your "Administrators" role */;
ParseRole moderators = /* Your "Moderators" role */;
moderators.getRoles().add(administrators);
moderators.saveInBackground();

Files

The ParseFile

ParseFile lets you store application files in the cloud that would otherwise be too large or cumbersome to fit into a regular ParseObject. The most common use case is storing images but you can also use it for documents, videos, music, and any other binary data.

Getting started with ParseFile is easy. First, you’ll need to have the data in byte[] form and then create a ParseFile with it. In this example, we’ll just use a string:

byte[] data = "Working at Parse is great!".getBytes();
ParseFile file = new ParseFile("resume.txt", data);

Notice in this example that we give the file a name of resume.txt. There’s two things to note here:

• You don’t need to worry about filename collisions. Each upload gets a unique identifier so there’s no problem with uploading multiple files named resume.txt.
• It’s important that you give a name to the file that has a file extension. This lets Parse figure out the file type and handle it accordingly. So, if you’re storing PNG images, make sure your filename ends with .png.

Next you’ll want to save the file up to the cloud. As with ParseObject, there are many variants of the save method you can use depending on what sort of callback and error handling suits you.

file.saveInBackground();

Finally, after the save completes, you can associate a ParseFile onto a ParseObject just like any other piece of data:

ParseObject jobApplication = new ParseObject("JobApplication");
jobApplication.put("applicantName", "Joe Smith");
jobApplication.put("applicantResumeFile", file);
jobApplication.saveInBackground();

Retrieving it back involves calling one of the getData variants on the ParseObject. Here we retrieve the resume file off another JobApplication object:

ParseFile applicantResume = (ParseFile)anotherApplication.get("applicantResumeFile");
applicantResume.getDataInBackground(new GetDataCallback() {
  public void done(byte[] data, ParseException e) {
    if (e == null) {
      // data has the bytes for the resume
    } else {
      // something went wrong
    }
  }
});

Just like on ParseObject, you will most likely want to use the background version of getData.

Progress

It’s easy to get the progress of both uploads and downloads using ParseFile by passing a ProgressCallback to saveInBackground and getDataInBackground. For example:

byte[] data = "Working at Parse is great!".getBytes();
ParseFile file = new ParseFile("resume.txt", data);

file.saveInBackground(new SaveCallback() {
  public void done(ParseException e) {
    // Handle success or failure here ...
  }
}, new ProgressCallback() {
  public void done(Integer percentDone) {
    // Update your progress spinner here. percentDone will be between 0 and 100.
  }
});

You can delete files that are referenced by objects using the REST API. You will need to provide the master key in order to be allowed to delete a file.

If your files are not referenced by any object in your app, it is not possible to delete them through the REST API. You may request a cleanup of unused files in your app’s Settings page. Keep in mind that doing so may break functionality which depended on accessing unreferenced files through their URL property. Files that are currently associated with an object will not be affected.

Using Parcelable

As most public facing components of the SDK, ParseFile implements the Parcelable interface. This means you can retain a ParseFile during configuration changes, or pass it to other components of the app through Bundles. To achieve this, depending on the context, use either Parcel#writeParcelable(Parcelable, int) or Bundle#putParcelable(String, Parcelable). For instance, in an Activity,

private ParseFile file;

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (!file.isDirty()) {
      outState.putParcelable("file", file);
    }
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
  if (savedInstanceState != null) {
    file = (ParseFile) savedInstanceState.getParcelable("file");
  }
}

Note, however, that files can’t be parceled if they are not saved on the server. If you try to do so, an exception will be thrown. If you are not sure if your file has been saved, please check for !isDirty() to be true before writing it to a parcel.

GeoPoints

Parse allows you to associate real-world latitude and longitude coordinates with an object. Adding a ParseGeoPoint to a ParseObject allows queries to take into account the proximity of an object to a reference point. This allows you to easily do things like find out what user is closest to another user or which places are closest to a user.

ParseGeoPoint

To associate a point with an object you first need to create a ParseGeoPoint. For example, to create a point with latitude of 40.0 degrees and -30.0 degrees longitude:

ParseGeoPoint point = new ParseGeoPoint(40.0, -30.0);

This point is then stored in the object as a regular field.

placeObject.put("location", point);

To retrieve a ParseGeoPoint from an object.

placeObject.getParseGeoPoint("location");

ParsePolygon

Parse allows you to associate polygon coordinates with an object. Adding a ParsePolygon to a ParseObject allows queries to determine whether a ParseGeoPoint is within a ParsePolygon or if a ParsePolygon contains a ParseGeoPoint .

• ParsePolygon must contain at least three coordinates.

For example, to create a polygon with coordinates (0, 0), (0, 1), (1, 1), (1, 0).

List<ParseGeoPoint> points = new ArrayList<ParseGeoPoint>();
points.add(new ParseGeoPoint(0,0));
points.add(new ParseGeoPoint(0,1));
points.add(new ParseGeoPoint(1,1));
points.add(new ParseGeoPoint(1,0));

ParsePolygon polygon = new ParsePolygon(points);

This point is then stored in the object as a regular field.

placeObject.put("bounds", polygon);

To retrieve a ParsePolygon from an object.

placeObject.getParsePolygon("bounds");

Geo Queries

Now that you have a bunch of objects with spatial coordinates, it would be nice to find out which objects are closest to a point. This can be done by adding another restriction to ParseQuery using whereNear. Getting a list of ten places that are closest to a user may look something like:

ParseGeoPoint userLocation = (ParseGeoPoint) userObject.get("location");
ParseQuery<ParseObject> query = ParseQuery.getQuery("PlaceObject");
query.whereNear("location", userLocation);
query.setLimit(10);
query.findInBackground(new FindCallback<ParseObject>() { ... });

At this point nearPlaces will be an array of objects ordered by distance (nearest to farthest) from userLocation. Note that if an additional orderByAscending()/orderByDescending() constraint is applied, it will take precedence over the distance ordering.

To limit the results using distance, check out whereWithinKilometers, whereWithinMiles, and whereWithinRadians.

It’s also possible to query for the set of objects that are contained within a particular area. To find the objects in a rectangular bounding box, add the whereWithinGeoBox restriction to your ParseQuery.

ParseGeoPoint southwestOfSF = new ParseGeoPoint(37.708813, -122.526398);
ParseGeoPoint northeastOfSF = new ParseGeoPoint(37.822802, -122.373962);
ParseQuery<ParseObject> query = ParseQuery.getQuery("PizzaPlaceObject");
query.whereWithinGeoBox("location", southwestOfSF, northeastOfSF);
query.findInBackground(new FindCallback<ParseObject>() { ... });

You can query for whether an object lies within or on a polygon of Parse.GeoPoint.

ParseGeoPoint point = new ParseGeoPoint(0.5, 0.5);
ParseQuery<ParseObject> query = ParseQuery.getQuery("PlaceObject");
query.wherePolygonContains("location", point);

You can also query for whether an object Parse.Polygon contains a Parse.GeoPoint.

ParseGeoPoint point = new ParseGeoPoint(0.5, 0.5);
ParseQuery<ParseObject> query = ParseQuery.getQuery("PlaceObject");
query.wherePolygonContains("location", point);

To efficiently find if a ParsePolygon contains a ParseGeoPoint without querying use containsPoint.

List<ParseGeoPoint> points = new ArrayList<ParseGeoPoint>();
points.add(new ParseGeoPoint(0, 0));
points.add(new ParseGeoPoint(0, 1));
points.add(new ParseGeoPoint(1, 1));
points.add(new ParseGeoPoint(1, 0));

ParseGeoPoint inside = new ParseGeoPoint(0.5, 0.5);
ParseGeoPoint outside = new ParseGeoPoint(10, 10);

ParsePolygon polygon = new ParsePolygon(points);

// Returns True
polygon.containsPoint(inside);

// Returns False
polygon.containsPoint(outside);

Utilizing Parcelable

As most public facing components of the SDK, ParseGeoPoint and ParsePolygon implements the Parcelable interface. This means you can retain a ParseGeoPoint and ParsePolygon during configuration changes, or pass it to other components of the app through Bundles. To achieve this, depending on the context, use either Parcel#writeParcelable(Parcelable, int) or Bundle#putParcelable(String, Parcelable). For instance, in an Activity,

private ParseGeoPoint point;

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelable("point", point);
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
  if (savedInstanceState != null) {
    point = (ParseGeoPoint) savedInstanceState.getParcelable("point");
  }
}

private ParsePolygon polygon;

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelable("polygon", polygon);
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
  if (savedInstanceState != null) {
    polygon = (ParsePolygon) savedInstanceState.getParcelable("polygon");
  }
}

Caveats

At the moment there are a couple of things to watch out for:

1. Each ParseObject class may only have one key with a ParseGeoPoint object.
2. Using the whereNear constraint will also limit results to within 100 miles.
3. Points should not equal or exceed the extreme ends of the ranges. Latitude should not be -90.0 or 90.0. Longitude should not be -180.0 or 180.0. Attempting to set latitude or longitude out of bounds will cause an error.

Local Datastore

The Parse Android SDK provides a local datastore which can be used to store and retrieve ParseObjects, even when the network is unavailable. To enable this functionality, simply call Parse.enableLocalDatastore() before your call to initialize.

import com.parse.Parse;
import android.app.Application;

public class App extends Application {
  @Override
  public void onCreate() {
    super.onCreate();

    Parse.enableLocalDatastore(this);
    Parse.initialize(this);
  }
}

If you use a Parse.Configuration.Builder, enable it there instead:

Parse.initialize(new Parse.Configuration.Builder(context)
  .server(...)
  .applicationId(...)
  .enableLocalDataStore()
  .build());

There are a couple of side effects of enabling the local datastore that you should be aware of. When enabled, there will only be one instance of any given ParseObject. For example, imagine you have an instance of the "GameScore" class with an objectId of "xWMyZ4YEGZ", and then you issue a ParseQuery for all instances of "GameScore" with that objectId. The result will be the same instance of the object you already have in memory.

Another side effect is that the current user and current installation will be stored in the local datastore, so you can persist unsaved changes to these objects between runs of your app using the methods below.

Calling the saveEventually method on a ParseObject will cause the object to be pinned in the local datastore until the save completes. So now, if you change the current ParseUser and call ParseUser.getCurrentUser().saveEventually(), your app will always see the changes that you have made.

Pinning

You can store a ParseObject in the local datastore by pinning it. Pinning a ParseObject is recursive, just like saving, so any objects that are pointed to by the one you are pinning will also be pinned. When an object is pinned, every time you update it by fetching or saving new data, the copy in the local datastore will be updated automatically. You don’t need to worry about it at all.

ParseObject gameScore = new ParseObject("GameScore");
gameScore.put("score", 1337);
gameScore.put("playerName", "Sean Plott");
gameScore.put("cheatMode", false);

gameScore.pinInBackground();

If you have multiple objects, you can pin them all at once with the pinAllInBackground convenience method.

ParseObject.pinAllInBackground(listOfObjects);

Retrieving

Storing objects is great, but it’s only useful if you can then get the objects back out later. To retrieve an object from the local datastore, call the fromLocalDatastore method to tell the ParseQuery where to look for its results.

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.fromLocalDatastore();

The only difference is that you won’t be able to access any data protected by Role based ACLs due to the fact that the Roles are stored on the server. To access this data protected by Role based ACLs, you may need to ignore ACLs when executing a Local Datastore query by calling the ignoreAcls method on the query. Note that after calling this, you cannot subsequently use the same query to load from the network.

// If data is protected by Role based ACLs:
query.ignoreAcls();

You can then retrieve objects as normal.

query.getInBackground("xWMyZ4YE", new GetCallback<ParseObject>() {
    public void done(ParseObject object, ParseException e) {
        if (e == null) {
            // object will be your game score
        } else {
            // something went wrong
        }
    }
});

Querying the Local Datastore

Often, you’ll want to find a whole list of objects that match certain criteria, instead of getting a single object by id. To do that, you can use a ParseQuery. Any ParseQuery can be used with the local datastore just as with the network. The results will include any object you have pinned that matches the query. Any unsaved changes you have made to the object will be considered when evaluating the query. So you can find a local object that matches, even if it was never returned from the server for this particular query.

ParseQuery<ParseObject> query = ParseQuery.getQuery("GameScore");
query.whereEqualTo("playerName", "Joe Bob");
query.fromLocalDatastore();
// If data is protected by Role based ACLs:
query.ignoreAcls();
query.findInBackground(new FindCallback<ParseObject>() {
    public void done(List<ParseObject> scoreList,
                     ParseException e) {
        if (e == null) {
            Log.d("score", "Retrieved " + scoreList.size());
        } else {
            Log.d("score", "Error: " + e.getMessage());
        }
    }
});

Unpinning

When you are done with an object and no longer need it to be in the local datastore, you can simply unpin it. This will free up disk space on the device and keep your queries on the local datastore running quickly.

gameScore.unpinInBackground();

There’s also a method to unpin several objects at once.

ParseObject.unpinAllInBackground(listOfObjects);

Pinning with Labels

Manually pinning and unpinning each object individual is a bit like using malloc and free. It is a very powerful tool, but it can be difficult to manage what objects get stored in complex scenarios. For example, imagine you are making a game with separate high score lists for global high scores and your friends’ high scores. If one of your friends happens to have a globally high score, you need to make sure you don’t unpin them completely when you remove them from one of the cached queries. To make these scenarios easier, you can also pin with a label. Labels indicate a group of objects that should be stored together.

// Add several objects with a label.
ParseObject.pinAllInBackground("MyScores", someGameScores);

// Add another object with the same label.
anotherGameScore.pinInBackground("MyScores");

To unpin all of the objects with the same label at the same time, you can pass a label to the unpin methods. This saves you from having to manually track which objects are in each group you care about.

ParseObject.unpinAllInBackground("MyScores");

Any object will stay in the datastore as long as it is pinned with any label. In other words, if you pin an object with two different labels, and then unpin it with one label, the object will stay in the datastore until you also unpin it with the other label.

Caching Query Results

Pinning with labels makes it easy to cache the results of queries. You can use one label to pin the results of each different query. To get new results from the network, just do a query and update the pinned objects.

ParseQuery<ParseObject> query = ParseQuery.getQuery(“GameScore");
query.orderByDescending(“score”);

// Query for new results from the network.
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(final List<ParseObject> scores, ParseException e) {
    // Remove the previously cached results.
    ParseObject.unpinAllInBackground(“highScores”, new DeleteCallback() {
    public void done(ParseException e) {
      // Cache the new results.
      ParseObject.pinAllInBackground(“highScores”, scores);
    }
  });
  }
});

When you want to get the cached results for the query, you can then run the same query against the local datastore.

ParseQuery<ParseObject> query = ParseQuery.getQuery(“GameScore");
query.orderByDescending(“score”);
query.fromLocalDatastore();

query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> scores, ParseException e) {
    // Yay! Cached scores!
  }
});

Syncing Local Changes

Once you’ve saved some changes locally, there are a few different ways you can save those changes back to Parse over the network. The easiest way to do this is with saveEventually. When you call saveEventually on a ParseObject, it will be pinned until it can be saved. The SDK will make sure to save the object the next time the network is available.

gameScore.saveEventually();

If you’d like to have more control over the way objects are synced, you can keep them in the local datastore until you are ready to save them yourself using saveInBackground. To manage the set of objects that need to be saved, you can again use a label. The fromPin method on ParseQuery makes it easy to fetch just the objects you care about.

ParseQuery<ParseObject> query = ParseQuery.getQuery(“GameScore");
query.fromPin(“MyChanges”);
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> scores, ParseException e) {
    for (ParseObject score in scores) {
      score.saveInBackground();
      score.unpinInBackground(“MyChanges”);
    }
  }
});

Push Notifications

Push notifications are a great way to keep your users engaged and informed about your app. You can reach your entire user base quickly and effectively. This guide will help you through the setup process and the general usage of Parse to send push notifications.

If you haven’t installed the SDK yet, head over to the Push QuickStart to get our SDK up and running.

Setting Up Push

If you want to start using push, start by completing the Android Push Notifications QuickStart Guide to learn how to configure your app and send your first push notification. Come back to this guide afterwards to learn more about the push features offered by Parse.

The Parse library provides push notifications using Firebase Cloud Messaging (FCM) if Google Play Services are available. Learn more about Google Play Services here.

Installations

Every Parse application installed on a device registered for push notifications has an associated Installation object. The Installation object is where you store all the data needed to target push notifications. For example, in a baseball app, you could store the teams a user is interested in to send updates about their performance. Saving the Installation object is also required for tracking push-related app open events.

In Android, Installation objects are available through the ParseInstallation class, a subclass of ParseObject. It uses the same API for storing and retrieving data. To access the current Installation object from your Android app, use the ParseInstallation.getCurrentInstallation() method. The first time you save a ParseInstallation, Parse will add it to your Installation class and it will be available for targeting push notifications.

// Save the current Installation to Parse.
ParseInstallation.getCurrentInstallation().saveInBackground();

While it is possible to modify a ParseInstallation just like you would a ParseObject, there are several special fields that help manage and target devices.

• channels: An array of the channels to which a device is currently subscribed.
• installationId: Unique Id for the device used by Parse (readonly).
• deviceType: The type of device, “ios”, “osx”, “android”, “winrt”, “winphone”, “dotnet”, or “embedded”. On Android devices, this field will be set to “android” (readonly).
• pushType: This field is reserved for directing Parse to the push delivery network to be used. If the device is registered to receive pushes via FCM, this field will be marked “gcm”. If Google Play Services is not available, it will be blank (readonly).
• deviceToken: The token used by FCM to keep track of registration ID. On iOS devices, this is a generated token (readonly).
• appName: The display name of the client application to which this installation belongs. This value is synchronized every time a ParseInstallation object is saved from the device (readonly).
• appVersion: The version string of the client application to which this installation belongs. This value is synchronized every time a ParseInstallation object is saved from the device (readonly).
• parseVersion: The version of the Parse SDK which this installation uses. This value is synchronized every time a ParseInstallation object is saved from the device (readonly).
• timeZone: The current time zone where the target device is located. This value is synchronized every time a ParseInstallation object is saved from the device (readonly).
• localeIdentifier: The locale identifier of the device in the format [language code]-[COUNTRY CODE]. The language codes are two-letter lowercase ISO language codes (such as “en”) as defined by ISO 639-1. The country codes are two-letter uppercase ISO country codes (such as “US”) as defined by ISO 3166-1. This value is synchronized every time a ParseInstallation object is saved from the device (readonly).
• badge: The current value of the icon badge for iOS apps. Changes to this value on the server will be used for future badge-increment push notifications.
• channelUris: The Microsoft-generated push URIs for Windows devices (readonly).
• appIdentifier: A unique identifier for this installation’s client application. This parameter is not supported in Android (readonly).

The Parse Android SDK will avoid making unnecessary requests. If a ParseInstallation is saved on the device, a request to the Parse servers will only be made if one of the ParseInstallation’s fields has been explicitly updated.

Sending Pushes

There are two ways to send push notifications using Parse: channels and advanced targeting. Channels offer a simple and easy to use model for sending pushes, while advanced targeting offers a more powerful and flexible model. Both are fully compatible with each other and will be covered in this section.

Sending notifications is often done from the Parse Dashboard push console, the REST API or from Cloud Code. However, push notifications can also be triggered by the existing client SDKs. If you decide to send notifications from the client SDKs, you will need to set Client Push Enabled in the Push Notifications settings of your Parse app.

However, be sure you understand that enabling Client Push can lead to a security vulnerability in your app. We recommend that you enable Client Push for testing purposes only, and move your push notification logic into Cloud Code when your app is ready to go into production.

You can view your past push notifications on the Parse Dashboard push console for up to 30 days after creating your push. For pushes scheduled in the future, you can delete the push on the push console as long as no sends have happened yet. After you send the push, the push console shows push analytics graphs.

Using Channels

The simplest way to start sending notifications is using channels. This allows you to use a publisher-subscriber model for sending pushes. Devices start by subscribing to one or more channels, and notifications can later be sent to these subscribers. The channels subscribed to by a given Installation are stored in the channels field of the Installation object.

Subscribing to Channels

A channel is identified by a string that starts with a letter and consists of alphanumeric characters, underscores, and dashes. It doesn’t need to be explicitly created before it can be used and each Installation can subscribe to any number of channels at a time.

Subscribing to a channel can be done using a single method call. For example, in a baseball score app, we could do:

// When users indicate they are Giants fans, we subscribe them to that channel.
ParsePush.subscribeInBackground("Giants");

By default, the main activity for your app will be run when a user responds to notifications.

Once subscribed to the “Giants” channel, your Installation object should have an updated channels field.

Unsubscribing from a channel is just as easy:

// When users indicate they are no longer Giants fans, we unsubscribe them.
ParsePush.unsubscribeInBackground("Giants");

You can also get the set of channels that the current device is subscribed to using:

List<String> subscribedChannels = ParseInstallation.getCurrentInstallation().getList("channels");

Neither the subscribe method nor the unsubscribe method blocks the thread it is called from. The subscription information is cached on the device’s disk if the network is inaccessible and transmitted to your Parse Server as soon as the network is usable. This means you don’t have to worry about threading or callbacks while managing subscriptions.

Sending Pushes to Channels

In the Android SDK, the following code can be used to alert all subscribers of the “Giants” channel that their favorite team just scored. This will display a notification center alert to iOS users and a system tray notification to Android users.

ParsePush push = new ParsePush();
push.setChannel("Giants");
push.setMessage("The Giants just scored! It's now 2-2 against the Mets.");
push.sendInBackground();

If you want to target multiple channels with a single push notification, you can use a LinkedList of channels.

LinkedList<String> channels = new LinkedList<String>();
channels.add("Giants");
channels.add("Mets");

ParsePush push = new ParsePush();
push.setChannels(channels); // Notice we use setChannels not setChannel
push.setMessage("The Giants won against the Mets 2-3.");
push.sendInBackground();

Using Advanced Targeting

While channels are great for many applications, sometimes you need more precision when targeting the recipients of your pushes. Parse allows you to write a query for any subset of your Installation objects using the querying API and to send them a push.

Since ParseInstallation is a subclass of ParseObject, you can save any data you want and even create relationships between Installation objects and your other objects. This allows you to send pushes to a very customized and dynamic segment of your user base.

Saving Installation Data

Storing data on a ParseInstallation object is just as easy as storing any other data on Parse. In our Baseball app, we could allow users to get pushes about game results, scores and injury reports.

// Store app language and version
ParseInstallation installation = ParseInstallation.getCurrentInstallation();
installation.put("scores",true);
installation.put("gameResults",true);
installation.put("injuryReports",true);
installation.saveInBackground();

You can even create relationships between your Installation objects and other classes saved on Parse. To associate a ParseInstallation with a particular user, for example, you can simply store the current user on the ParseInstallation.

// Associate the device with a user
ParseInstallation installation = ParseInstallation.getCurrentInstallation();
installation.put("user",ParseUser.getCurrentUser());
installation.saveInBackground();

Sending Pushes to Queries

Once you have your data stored on your ParseInstallation objects, you can use a ParseQuery to target a subset of these devices. ParseInstallation queries work just like any other Parse query, but we use the special static method ParseInstallation.getQuery() to create it. We set this query on our ParsePush object, before sending the notification.

// Create our Installation query
ParseQuery pushQuery = ParseInstallation.getQuery();
pushQuery.whereEqualTo("injuryReports", true);

// Send push notification to query
ParsePush push = new ParsePush();
push.setQuery(pushQuery); // Set our Installation query
push.setMessage("Willie Hayes injured by own pop fly.");
push.sendInBackground();

We can even use channels with our query. To send a push to all subscribers of the “Giants” channel but filtered by those who want score update, we can do the following:

// Create our Installation query
ParseQuery pushQuery = ParseInstallation.getQuery();
pushQuery.whereEqualTo("channels", "Giants"); // Set the channel
pushQuery.whereEqualTo("scores", true);

// Send push notification to query
ParsePush push = new ParsePush();
push.setQuery(pushQuery);
push.setMessage("Giants scored against the A's! It's now 2-2.");
push.sendInBackground();