MauroCerbai

Hey,
First of all take a deep look at part 1 available here.
Instead what's new on part 2? Well basically two things:

in part 1 we built an app to receive constant location update, so this time we will see how to get just on time only
we will see how activity recognition works

Part 1 - Getting the last known location

So, how to receive the last gps location once from the google api services?

Follow every instruction of the part 1 and then on the onConnected method write this:

@Override
public void onConnected(@Nullable Bundle bundle) {
    mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
    if (mLastLocation != null) {
        mLatitude.setText(String.valueOf(mLastLocation.getLatitude()));
        mLatitude.setText(String.valueOf(mLastLocation.getLongitude()));
    }
}

Part 2 - Activity Recognition

Add the permission in your app manifest file:

<uses-permission android:name="com.google.android.gms.permTission.ACTIVITY_RECOGNITION" />

Then to handle the activity recognition in background we are gonna use an IntentService:

public class DetectedActivitiesIntentService extends IntentService {
    protected static final String TAG = "detections_is";
    public static final String BROADCAST_ACTION = "com.maurocerbai.googleaudacitylocationpart2.BROADCASTACTION";
    public static final String ACTIVITY_EXTRA = "com.maurocerbai.googleaudacitylocationpart2.ACTIVITYEXTRA";
    public DetectedActivitiesIntentService() {
        super(TAG);
    }
    @Override    protected void onHandleIntent(Intent intent) {
        ActivityRecognitionResult result = ActivityRecognitionResult.extractResult(intent);
        Intent localIntent = new Intent(BROADCAST_ACTION);
        ArrayList <DetectedActivity> detectedActivities = (ArrayList) result.getProbableActivities();
        localIntent.putExtra(ACTIVITY_EXTRA,detectedActivities);
        LocalBroadcastManager.getInstance(this).sendBroadcast(localIntent);
    }
}

Don't forget to declare this service in the manifest:

<service android:name=".DetectedActivitiesIntentService"    android:exported="false" />

In your main activity build your goolge api connection as seen in part 1 but instead of location use activityrecognition as shown here:

private void buildGoogleApiClient() {
    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(ActivityRecognition.API)
            .build();
}

and add the possibility to listen to the broadcast you made before in a inner class:

class ActivityDetectionBroadcastReceiver extends BroadcastReceiver{
    @Override    public void onReceive(Context context, Intent intent) {
        ArrayList <DetectedActivity> detectedActivities = intent.getParcelableArrayListExtra(Constants.ACTIVITY_EXTRA);
        String res = "";
        for (DetectedActivity d:detectedActivities)
            res+=d.getType()+" "+d.getConfidence();
        text_label.setText(res);
    }
}

Then a this two method and link them to the button of the view:

public void requestActivityUpdateButtonHandler (View view){
    ActivityRecognition.ActivityRecognitionApi.requestActivityUpdates(mGoogleApiClient,1000,getActivityDetectionPendingIntent()).setResultCallback(this);
}
public void removeActivityUpdateButtonHandler (View view){
    ActivityRecognition.ActivityRecognitionApi.removeActivityUpdates(mGoogleApiClient,getActivityDetectionPendingIntent()).setResultCallback(this);
}

Don't forget to handle the activity lifecycle adding this two method:

@Override protected void onResume() {
    super.onResume();
    LocalBroadcastManager.getInstance(this).registerReceiver(mActivityDetectionBroadcastReceiver,new IntentFilter(Constants.BROADCAST_ACTION));
}
@Override protected void onPause() {
    LocalBroadcastManager.getInstance(this).unregisterReceiver(mActivityDetectionBroadcastReceiver);
    super.onPause();
}

DONE. Good luck testing it because the emulator is not very helpful in this case. Maybe using a GPX file you can simulate the movements using the latest version of the sdk tools.
You can find the code here : https://bitbucket.org/mcmaur/googleaudacitylocationpart2

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"One of the unique features of mobile applications is location awareness. Mobile users take their devices with them everywhere, and adding location awareness to your app offers users a more contextual experience. The location APIs available in Google Play services facilitate adding location awareness to your app with automated location tracking, geofencing, and activity recognition."

How to do that? Never been so simple:

Create a Google Api Client that use the api you need

mGoogleApiClient = new GoogleApiClient.Builder(this)

.addApi(LocationServices.API)

.addConnectionCallbacks(this)

.addOnConnectionFailedListener(this)

.build();

Implements

GoogleApiClientConnectionCallbacks
GoogleApiClient.onConnectionFailedListener
LocationListener

Wait for a onConnected callback and ask for updates on location

mLocationRequest = LocationRequest.create()

.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)

.setInterval(1000);

LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,mLocationRequest,this);

Wait for an other callback OnLocationChanged

@Override

public void onLocationChanged(Location location) {

Log.d(LOG_TAG,"location: "+location.toString());

}

!NB: rembember to set:

the permission on the manifest file

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>

2.Add the play services library in the manifest like this

3. Add the lib to build gradle

compile 'com.google.android.gms:play-services:8.4.0'

Do not forget to call the appropiate method in order to deal with the activity lifecycle:

  @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }

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