ReactiveLocation library for Android

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

Current stable version - 0.9

This version works with Google Play Services 8.4.0 and RxJava 1.1.+

What can you do with that?

• easily connect to Play Services API
• obtain last known location
• subscribe for location updates
• use location settings API
• manage geofences
• geocode location to list of addresses
• activity recognition
• use current place API
• fetch place autocomplete suggestions

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 = 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();

Subscribing for Activity Recognition

Getting activity recognition is just as simple

ReactiveLocationProvider locationProvider = new ReactiveLocationProvider(context);
Subscription subscription = locationProvider.getDetectedActivity(0) // detectionIntervalMillis
    .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<ActivityRecognitionResult>() {
        @Override
        public void call(ActivityRecognitionResult detectedActivity) {
            doSthImportantWithObtainedActivity(detectedActivity);
        }
    });

Reverse geocode location

Do you need address for location?

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

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

Geocode location

Do you need address for a text search query?

Observable<List<Address>> geocodeObservable = locationProvider
    .getGeocodeObservable(String userQuery, MAX_ADDRESSES);

geocodeObservable
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe(...);

Managing geofences

For geofence management use addGeofences and removeGeofences methods.

Checking location settings though location settings API

To get LocationSettingsResponse for your LocationRequest check out ReactiveLocationProvider.checkLocationSettings() method. Sample usage can be found in sample project in MainActivity class.

Connecting to Google Play Services API

If you just need managed connection to Play Services API use ReactiveLocationProvider.getGoogleApiClientObservable(). On subscription it will connect to the API. Unsubscription will close the connection.

Creating observable from PendingResult

If you are manually using Google Play Services and you are dealing with PendingResult you can easily transform them to observables with ReactiveLocationProvider.fromPendingResult() method.

Transforming buffers to observable

To transform any buffer to observable and autorelease it on unsubscription use DataBufferObservable.from() method. It will let you easily flatMap such data as PlaceLikelihoodBuffer or AutocompletePredictionBuffer from Places API. For usage example see PlacesActivity sample.

Places API

You can fetch current place or place suggestions using:

• ReactiveLocationProvider.getCurrentPlace()
• ReactiveLocationProvider.getPlaceAutocompletePredictions()
• ReactiveLocationProvider.getPlaceById()

For more info see sample project and PlacesActivity.

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.just((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:0.9@aar'
    compile 'com.google.android.gms:play-services-location:8.4.0' //you can use newer GMS version if you need
    compile 'io.reactivex:rxjava:1.1.5' //you can override RxJava version if you need

    //RxAndroid nor NotRxAndroid is not required by library
    compile 'io.reactivex:rxandroid:0.25.0'
}

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>0.8</version>
    <type>aar</type>
</dependency>

It may be necessary to add google play services and rxanroid dependency as well.

Sample

Sample usage is available in sample directory.

Places API requires API Key. Before running samples you need to create project on API console and obtain API Key using this guide. Obtained key should be exported as gradle property named: REACTIVE_LOCATION_GMS_API_KEY for example in ~/.gradle/gradle.properties.

References

If you need Google Fit library rxified please take a look at RxFit.

License

Copyright (C) 2015 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.