ReactiveLocation library for Android

Small library that wraps Google Play Services API in brilliant RxJava Observables reducing boilerplate to minimum.

This library is still in its early beta.

What can you do with that?

• obtain last known location
• subscribe for location updates
• manage geofences
• geocode location to list of addresses

How does the API look like?

Simple. All you need is to create ReactiveLocationProvider using your context. All observables are already there. Examples are worth more than 1000 words:

Getting last known location

ReactiveLocationProvider locationProvider = new ReactiveLocationProvider(context);
locationProvider.getLastKnownLocation()
    .subscribe(new Action1<Location>() {
        @Override
        public void call(Location location) {
            doSthImportantWithObtainedLocation(location);
        }
    });

Yep, Java 8 is not there yet (and on Android it will take a while) but there is absolutely no Google Play Services LocationClient callbacks hell and there is no clean-up you have to do.

Subscribing for location updates

LocationRequest request = LocationRequest.create() //standard GMS LocationRequest
                                  .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                                  .setNumUpdates(5)
                                  .setInterval(100);

ReactiveLocationProvider locationProvider = new ReactiveLocationProvider(context);
Subscription subscription = locationUpdatesObservable = locationProvider.getUpdatedLocation(request)
    .filter(...)    // you can filter location updates
    .map(...)       // you can map location to sth different
    .flatMap(...)   // or event flat map
    ...             // and do everything else that is provided by RxJava
    .subscribe(new Action1<Location>() {
        @Override
        public void call(Location location) {
            doSthImportantWithObtainedLocation(location);
        }
    });

When you are done (for example in onStop()) remember to unsubscribe.

subscription.unsubscribe();

Geocode location

Do you need address for location?

Observable<List<Address> geocodeObservable = locationProvider
    .getGeocodeObservable(location.getLatitude(), location.getLongitude(), MAX_ADDRESSES);

geocodeObservable
    .subscribeOn(Schedulers.io())               // use I/O thread to query for addresses
    .observeOn(AndroidSchedulers.mainThread())  // return result in main android thread to manipulate UI
    .subscribe(...);

Managing geofences

For geofence management use addGeofences and removeGeofences methods.

Cooler examples

Do you need location with certain accuracy but don't want to wait for it more than 4 sec? No problem.

LocationRequest req = LocationRequest.create()
                         .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                         .setExpirationDuration(TimeUnit.SECONDS.toMillis(LOCATION_TIMEOUT_IN_SECONDS)
                         .setInterval(LOCATION_UPDATE_INTERVAL);

Observable<Location> goodEnoughQuicklyOrNothingObservable = locationProvider.getUpdatedLocation(req)
            .filter(new Func1<Location, Boolean>() {
                @Override
                public Boolean call(Location location) {
                    return location.getAccuracy() < SUFFICIENT_ACCURACY;
                }
            })
            .timeout(LOCATION_TIMEOUT_IN_SECONDS, TimeUnit.SECONDS, Observable.from((Location) null), AndroidSchedulers.mainThread())
            .first()
            .observeOn(AndroidSchedulers.mainThread());

goodEnoughQuicklyOrNothingObservable.subscribe(...);

How to use it?

Library is available in maven central.

Gradle

Just use it as dependency in your build.gradle file along with Google Play Services and RxJava.

dependencies {
    ...
    compile 'pl.charmas.android:android-reactive-location:0.1@aar'
    compile 'com.google.android.gms:play-services:4.1.32'
    compile 'com.netflix.rxjava:rxjava-android:0.16.1'
}

Maven

Ensure you have android-maven-plugin version that support *aar archives and add following dependency:

<dependency>
    <groupId>pl.charmas.android</groupId>
    <artifactId>android-reactive-location</artifactId>
    <version>0.1</version>
    <type>aar</type>
</dependency>

It may be necessary to add google play services and rxjava-android dependency as well.

Sample

Sample usage is available in sample directory.

License

Copyright (C) 2014 Michał Charmas (http://blog.charmas.pl)

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.