Fast Step-by-Step to Get Location

by Philip Barlow / from beautifuldecay.com

Configuration

Add Gradle dependency:

	dependencies {
	compile 'com.google.android.gms:play-services:8.1.0'
	}

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build.gradle

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Add permission on AndroidManifest.xml

	<manifest xmlns:android="http://schemas.android.com/apk/res/android"
	package="com.tassioauad.locationexample">

	<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
	<!– AND/OR –>
	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

	<!– … –>

	</manifest>

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AndroidManifest.xml

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More about ACCESS_COARSE_LOCATION and ACCESS_FINE_LOCATION.

Using the GoogleApiClient

At first, we need to instanciate the GoogleApiClient, because throught this instance we can access any service from Google Services, like the Location Service. It is a client for ALL services of the Google Service API (Location, ActivityRecognition and etc..).

This Activity below shows how it happens:

	public class LocationActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {

	private GoogleApiClient googleApiClient;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);

	googleApiClient = new GoogleApiClient.Builder(this)
	.addConnectionCallbacks(this) //Be aware of state of the connection
	.addOnConnectionFailedListener(this) //Be aware of failures
	.build();

	//Trying to connect with Google API. If it works onConnected() will be called, else onConnectionFailed() will be called.
	googleApiClient.connect();

	}

	@Override
	protected void onStop() {
	super.onStop();
	stopGoogleApiConnection();
	}

	public void stopGoogleApiConnection() {
	//Stopping the Connection
	if (googleApiClient.isConnected()) {
	googleApiClient.disconnect(); //Closing connection with Google APIs
	}
	}

	/**
	* After calling connect(), this method will be invoked asynchronously when the connect request has successfully completed.
	* After this callback, the application can make requests on other methods provided by the client and expect that no user intervention
	* is required to call methods that use account and scopes provided to the client constructor.
	*
	* @param bundle
	*/
	@Override
	public void onConnected(Bundle bundle) {
	//Google API connection has been done successfully
	}

	/**
	* Called when the client is temporarily in a disconnected state.
	* This can happen if there is a problem with the remote service (e.g. a crash or resource problem causes it to be killed by the system).
	* When called, all requests have been canceled and no outstanding listeners will be executed.
	* GoogleApiClient will automatically attempt to restore the connection.
	* Applications should disable UI components that require the service, and wait for a call to onConnected(Bundle) to re-enable them.
	*/
	@Override
	public void onConnectionSuspended(int i) {
	//Wait for the GoogleApiClient restores the connection.
	}

	/**
	* Called when there was an error connecting the client to the service.
	*
	* @param connectionResult
	*/
	@Override
	public void onConnectionFailed(ConnectionResult connectionResult) {
	//Google API connection has been failed! Stop it and warn!
	stopGoogleApiConnection();
	}
	}

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LocationActivity.java

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When the connection with the API is done, we can use the services of the API.

Adding the Location Service API

It’s easy, just add the API reference during the GoogleApiClient instanciation:

	googleApiClient = new GoogleApiClient.Builder(this)
	.addConnectionCallbacks(this)
	.addOnConnectionFailedListener(this)
	.addApi(LocationServices.API)
	.build();

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Example.java

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Now, when the Google API Client get ready to be used, the Location Service will be ready too and we can call methods of LocationServices.FusedLocationApi:

Getting Last Location

Throught the LocationServices.FusedLocationApi we can get the last location:

	@Override
	public void onConnected(Bundle bundle) {
	//Google API connection has been done successfully
	Location lastLocation = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
	}

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onConnected.java

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Requesting Location Updates

If we want to get the location everytime it changes, we can set an listener to receive the current location instance:

Instead of use the getLastLocation() we gonna use the requestLocationUpdates(). We have to set the updates configuration (time interval, min displacement in meter and etc) through an instance of com.google.android.gms.location.LocationRequest and we have to set the listener that will receive the updates.

	@Override
	public void onConnected(Bundle bundle) {
	//Google API connection has been done successfully
	LocationRequest locationRequest = new LocationRequest();
	locationRequest.setInterval(10000);
	locationRequest.setFastestInterval(5000);
	locationRequest.setSmallestDisplacement(5);
	locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
	LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, new LocationListener() {
	@Override
	public void onLocationChanged(Location location) {

	}
	});
	}

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OnConnected.java

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Ops! Don’t forget to remove the listener when you close the connection with the Google API. We gonna do it using the method removeLocationUpdates of the class LocationServices.FusedLocationApi.

	@Override
	public void stopToCaptureLocations() {
	if (googleApiClient.isConnected()) {
	LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient, locationListener); //Stopping to get location updates
	googleApiClient.disconnect(); //Closing connection with Google APIs
	}
	}