Current Location Update

Android offers so many API to find the location till froyo version we had only request location updates and it will eat up the battery with continuous updates.
There is a new API introduced in 2.3 to obtain single update of GPS.

An simple example to obtain location (single update) is as below:

1. Register a receiver to listen to intent – “SINGLE_LOCATION_UPDATE_ACTION”
   registerReceiver(singleUpdateReceiver,new IntentFilter(SINGLE_LOCATION_UPDATE_ACTION));
2. Get the instance of location manger service
   locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
3. Create criteria instance and set accuracy as required
   criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_LOW);
4. Create a pendingIntent instance. Pendingintent is registered to receive broadcast with action “SINGLE_LOCATION_UPDATE_ACTION” from the location manager
   Intent updateIntent = new Intent(SINGLE_LOCATION_UPDATE_ACTION);
singleUpatePI = PendingIntent.getBroadcast(this, 0, updateIntent, PendingIntent.FLAG_UPDATE_CURRENT);
5. Finally, request for single update
   locationManager.requestSingleUpdate(criteria, singleUpatePI);
6. We need to declare the receiver with onReceive function as below
   protected BroadcastReceiver singleUpdateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(TAG,"onReceive");
//unregister the receiver so that the application does not keep listening the broadcast even after the broadcast is received.
        context.unregisterReceiver(singleUpdateReceiver);

   // get the location from the intent send in broadcast using the key - this step is very very important
        String key = LocationManager.KEY_LOCATION_CHANGED;
        Location location = (Location)intent.getExtras().get(key);

   // Call the function required
        if (location != null) {
            onLocationChanged(location);
        }

   // finally remove the updates for the pending intent
        locationManager.removeUpdates(singleUpatePI);
    }
};