# geofire-android **Repository Path**: mirrors_firebase/geofire-android ## Basic Information - **Project Name**: geofire-android - **Description**: GeoFire for Android apps - **Primary Language**: Unknown - **License**: Apache-2.0 - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2020-08-08 - **Last Updated**: 2025-12-20 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # GeoFire for Android — Realtime location queries with Firebase [![Actions Status][gh-actions-badge]][gh-actions] GeoFire is an open-source library for Android that allows you to store and query a set of keys based on their geographic location. At its heart, GeoFire simply stores locations with string keys. Its main benefit however, is the possibility of querying keys within a given geographic area - all in realtime. GeoFire uses the [Firebase Realtime Database](https://firebase.google.com/products/realtime-database/) for data storage, allowing query results to be updated in realtime as they change. GeoFire *selectively loads only the data near certain locations, keeping your applications light and responsive*, even with extremely large datasets. GeoFire clients are also available for other languages: * [Objective-C (iOS)](https://github.com/firebase/geofire-objc) * [JavaScript (Web)](https://github.com/firebase/geofire-js) * [Java (Server)](https://github.com/firebase/geofire-java) ### Integrating GeoFire with your data GeoFire is designed as a lightweight add-on to the Firebase Realtime Database. However, to keep things simple, GeoFire stores data in its own format and its own location within your Firebase database. This allows your existing data format and security rules to remain unchanged and for you to add GeoFire as an easy solution for geo queries without modifying your existing data. ### Example Usage Assume you are building an app to rate bars and you store all information for a bar, e.g. name, business hours and price range, at `/bars/`. Later, you want to add the possibility for users to search for bars in their vicinity. This is where GeoFire comes in. You can store the location for each bar using GeoFire, using the bar IDs as GeoFire keys. GeoFire then allows you to easily query which bar IDs (the keys) are nearby. To display any additional information about the bars, you can load the information for each bar returned by the query at `/bars/`. ## Including GeoFire in your Android project In order to use GeoFire in your project, you need to [add the Firebase Android SDK](https://firebase.google.com/docs/android/setup). After that you can include GeoFire with one of the choices below. Add a dependency for GeoFire to your app's `build.gradle` file. ```groovy dependencies { // Full GeoFire library for Realtime Database users implementation 'com.firebase:geofire-android:3.2.0' // GeoFire utililty functions for Cloud Firestore users who // want to implement their own geo solution, see: // https://firebase.google.com/docs/firestore/solutions/geoqueries implementation 'com.firebase:geofire-android-common:3.2.0' } ``` ## Usage There are two ways to use GeoFire: - GeoFire - an end-to-end solution for adding simple geo queries to apps using Firebase Realtime Database. - GeoFireUtils - a set of utilities that make it simple to build a geo query solution for any app, such as those using Cloud Firestore. ### GeoFire A `GeoFire` object is used to read and write geo location data to your Firebase database and to create queries. To create a new `GeoFire` instance you need to attach it to a Firebase database reference. ```java DatabaseReference ref = FirebaseDatabase.getInstance().getReference("path/to/geofire"); GeoFire geoFire = new GeoFire(ref); ``` Note that you can point your reference to anywhere in your Firebase database, but don't forget to [setup security rules for GeoFire](https://github.com/firebase/geofire-js/blob/master/examples/securityRules). #### Setting location data In GeoFire you can set and query locations by string keys. To set a location for a key simply call the `setLocation` method. The method is passed a key as a string and the location as a `GeoLocation` object containing the location's latitude and longitude: ```java geoFire.setLocation("firebase-hq", new GeoLocation(37.7853889, -122.4056973)); ``` To check if a write was successfully saved on the server, you can add a `GeoFire.CompletionListener` to the `setLocation` call: ```java geoFire.setLocation("firebase-hq", new GeoLocation(37.7853889, -122.4056973), new GeoFire.CompletionListener() { @Override public void onComplete(String key, FirebaseError error) { if (error != null) { System.err.println("There was an error saving the location to GeoFire: " + error); } else { System.out.println("Location saved on server successfully!"); } } }); ``` To remove a location and delete it from the database simply pass the location's key to `removeLocation`: ```java geoFire.removeLocation("firebase-hq"); ``` #### Retrieving a location Retrieving a location for a single key in GeoFire happens with callbacks: ```java geoFire.getLocation("firebase-hq", new LocationCallback() { @Override public void onLocationResult(String key, GeoLocation location) { if (location != null) { System.out.println(String.format("The location for key %s is [%f,%f]", key, location.latitude, location.longitude)); } else { System.out.println(String.format("There is no location for key %s in GeoFire", key)); } } @Override public void onCancelled(DatabaseError databaseError) { System.err.println("There was an error getting the GeoFire location: " + databaseError); } }); ``` ### Geo Queries GeoFire allows you to query all keys within a geographic area using `GeoQuery` objects. As the locations for keys change, the query is updated in realtime and fires events letting you know if any relevant keys have moved. `GeoQuery` parameters can be updated later to change the size and center of the queried area. ```java // creates a new query around [37.7832, -122.4056] with a radius of 0.6 kilometers GeoQuery geoQuery = geoFire.queryAtLocation(new GeoLocation(37.7832, -122.4056), 0.6); ``` #### Receiving events for geo queries ##### Key Events There are five kinds of "key" events that can occur with a geo query: 1. **Key Entered**: The location of a key now matches the query criteria. 2. **Key Exited**: The location of a key no longer matches the query criteria. 3. **Key Moved**: The location of a key changed but the location still matches the query criteria. 4. **Query Ready**: All current data has been loaded from the server and all initial events have been fired. 5. **Query Error**: There was an error while performing this query, e.g. a violation of security rules. Key entered events will be fired for all keys initially matching the query as well as any time afterwards that a key enters the query. Key moved and key exited events are guaranteed to be preceded by a key entered event. Sometimes you want to know when the data for all the initial keys has been loaded from the server and the corresponding events for those keys have been fired. For example, you may want to hide a loading animation after your data has fully loaded. This is what the "ready" event is used for. Note that locations might change while initially loading the data and key moved and key exited events might therefore still occur before the ready event is fired. When the query criteria is updated, the existing locations are re-queried and the ready event is fired again once all events for the updated query have been fired. This includes key exited events for keys that no longer match the query. To listen for events you must add a `GeoQueryEventListener` to the `GeoQuery`: ```java geoQuery.addGeoQueryEventListener(new GeoQueryEventListener() { @Override public void onKeyEntered(String key, GeoLocation location) { System.out.println(String.format("Key %s entered the search area at [%f,%f]", key, location.latitude, location.longitude)); } @Override public void onKeyExited(String key) { System.out.println(String.format("Key %s is no longer in the search area", key)); } @Override public void onKeyMoved(String key, GeoLocation location) { System.out.println(String.format("Key %s moved within the search area to [%f,%f]", key, location.latitude, location.longitude)); } @Override public void onGeoQueryReady() { System.out.println("All initial data has been loaded and events have been fired!"); } @Override public void onGeoQueryError(DatabaseError error) { System.err.println("There was an error with this query: " + error); } }); ``` You can call either `removeGeoQueryEventListener` to remove a single event listener or `removeAllListeners` to remove all event listeners for a `GeoQuery`. ##### Data Events If you are storing model data and geo data in the same database location, you may want access to the `DataSnapshot` as part of geo events. In this case, use a `GeoQueryDataEventListener` rather than a key listener. These "data event" listeners have all of the same events as the key listeners with one additional event type: 6. **Data Changed**: the underlying `DataSnapshot` has changed. Every "data moved" event is followed by a data changed event but you can also get change events without a move if the data changed does not affect the location. Adding a data event listener is similar to adding a key event listener: ```java geoQuery.addGeoQueryDataEventListener(new GeoQueryDataEventListener() { @Override public void onDataEntered(DataSnapshot dataSnapshot, GeoLocation location) { // ... } @Override public void onDataExited(DataSnapshot dataSnapshot) { // ... } @Override public void onDataMoved(DataSnapshot dataSnapshot, GeoLocation location) { // ... } @Override public void onDataChanged(DataSnapshot dataSnapshot, GeoLocation location) { // ... } @Override public void onGeoQueryReady() { // ... } @Override public void onGeoQueryError(DatabaseError error) { // ... } }); ``` #### Updating the query criteria The `GeoQuery` search area can be changed with `setCenter` and `setRadius`. Key exited and key entered events will be fired for keys moving in and out of the old and new search area, respectively. No key moved events will be fired; however, key moved events might occur independently. Updating the search area can be helpful in cases such as when you need to update the query to the new visible map area after a user scrolls. ### GeoFireUtils The `geofire-android-common` library provides the `GeoFireUtils` class which contains utilities for working with geohashes but has no dependency on or integration with a specific database. The `GeoFireUtils` class contains the following utility methods: * `String getGeoHashForLocation(@NonNull GeoLocation location)` - compute the geohash string for a given (lat,lng) par with default precision. * `String getGeoHashForLocation(@NonNull GeoLocation location, int precision)` - compute the geohash string for a given (lat, lng) pair with custom precision. * `double getDistanceBetween(@NonNull GeoLocation a, @NonNull GeoLocation b)` - compute the distance, in kilometers, between two locations. * `List getGeoHashQueryBounds(@NonNull GeoLocation location, double radius)` - given a center point and a radius distance, compute a set of query bounds that can be joined to find all points within the radius distance of the center. For a detailed guide on how to use these utilities to add geo querying capabilities to your Cloud Firestore app, see: https://firebase.google.com/docs/firestore/solutions/geoqueries ## Publishing ### Versioning We use [SemVer](https://semver.org/) in this project. When you bump a version, be sure to update: - [common/gradle.properties](common/gradle.properties) - [library/gradle.properties](library/gradle.properties) - [README.md](README.md) ### Credentials The library is published to Maven Central by the firebase-sonatype account, Googlers can find the password for this account in [Valentine](http://valentine/) ### GPG Key You will need to create a private GPG keyring on your machine, if you don't have one do the following steps: 1. Run `gpg --full-generate-key` 1. Choose `RSA and RSA` for the key type 1. Use `4096` for the key size 1. Use `0` for the expiration (never) 1. Use any name, email address, and password This creates your key in `~/.gnupg/openpgp-revocs.d/` with `.rev` format. The last 8 characters before the `.rev` extension are your **Key ID**. To export the key, run: ``` gpg --export-secret-keys -o $HOME/sonatype.gpg ``` Finally upload your key to the keyserver: ``` gpg --keyserver hkp://keys.openpgp.org --send-keys ``` ### Local Properties Open your `$HOME/.gradle/gradle.properties` file at and fill in the values: ``` signing.keyId= signing.password= signing.secretKeyRingFile= mavenCentralRepositoryUsername=firebase-sonatype mavenCentralRepositoryPassword= ``` ### Publish To publish, run: ``` ./gradlew publish ``` ### Release Follow [the instructions here](https://central.sonatype.org/pages/releasing-the-deployment.html): 1. Navigate to https://oss.sonatype.org/ and **Log In** 1. On the left side menu, click **Staging Repositories** (under **Build Promotion**) and look for the `com.firebase` repo 1. You should see it with the `Open` status. Click **Close** and wait a few minutes (you can check status by clicking **Refresh**) 1. Once the status changes to `Closed`, click **Release** [gh-actions]: https://github.com/firebase/geofire-android/actions [gh-actions-badge]: https://github.com/firebase/geofire-android/workflows/Android%20CI/badge.svg