从服务接收活动中的广播

Question

I have TrackingService component to track the location of the buses in my city based on Crowdsourcing. In the TrackingService class I have variable pLong, pLat to stored the latitude and longitude when they are calaculated in the onLocatiochChanged() . The TrackingService is operating in the background, then the data is transmitted to the server. I have an Map Activity to display the location of the buses, the user selected in the MainActivity( as Filter).

The background TrackingService is started in the MainActivity when the app launches.

I am trying to pass the pLat, pLong from the onLocationChanged() to the Map activity when the onLocationChanged() is being invoked to display the user's current location beside the bus's locations with the aid of BroadcastReceiver.

I have debugged my code and facing problem that I am getting 0.0 for the values lat, lng in the BroadcastReiceiver in the map activity also the bReceiver is being invoked.

How can I get it to work to retrieve the lat and lng vlaues in the BroadcastReceiver bReceiver ?

TrackingService class:

public class TrackingService extends Service implements
        LocationListener {
    public double pLong;
    public double pLat;
    ...
        @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        detectLocation();
        return START_STICKY;
    }
    private void detectLocation() {
        lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 30 * 1000, 0,
                this);
    }
    @Override
    public void onLocationChanged(Location location) {

        if (location != null) {
        pLong = location.getLongitude();
        pLat = location.getLatitude();

        Intent intent = new Intent(Map.RECEIVE_latLng);
        Bundle extras = new Bundle();
        extras.putDouble("lng", pLong);
        extras.putDouble("lat", pLat);
        intent.putExtras(extras);
        LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
        System.out.println("ABC TrackingService: "+ pLat + " ; " + pLong);
           .....

     }  

}

Map activity:

    public class Map extends FragmentActivity implements OnMapReadyCallback   {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.map);

        LocalBroadcastManager bManager = LocalBroadcastManager.getInstance(this);
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(RECEIVE_latLng);
        bManager.registerReceiver(bReceiver, intentFilter);

    }

public static final String RECEIVE_latLng = "com.bustracker.RECEIVE_latLng";
    private BroadcastReceiver bReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent.getAction().equals(RECEIVE_latLng)) {
             Bundle extras = getIntent().getExtras();
             if(!extras.isEmpty() && extras != null){
                 double lng = extras.getDouble("lng");
                 double lat = extras.getDouble("lat");
                 LatLng ll = new LatLng(lng,lat);
                 MarkerOptions markerOpt = new MarkerOptions().title("My Location")
                            .position(ll);
                 System.out.println("ABC map: "+ lat + " ; " + lng);
                 myLocatMarker = map.addMarker(markerOpt);

             }
            }
        }
    };



      }

output:

08-27 15:25:48.116: I/System.out(3260): ABC TrackingService: 63.86896885 ; 13.66557022
08-27 15:25:48.146: I/System.out(3260): ABC map: 0.0 ; 0.0

Answer 1

Inside onLocationChanged

    Intent intent = new Intent(Map.RECEIVE_latLng);
    intent.putExtra("location",location);
    sendBroadcast(intent);

onReceive

Location location = intent.getParcelableExtra("location");