GPS has opened a Pandora's box for mobile developer. There has been a huge influx of such application ranging from tracking apps to location based social networking apps.
Many of today's applications require us to get a GPS fix on the location of the device when the application is being used.
Therefore without further ado lets get into some coding.
The following snippet of codes employ a service and a broadcast receiver to get onto a location fix. It gets the most recent fix on the location and then closes the GPS updates as soon as it gets a fix.
public class FindGPSActivity extends Activity{
Intent myGpsService;
MainGpsReciever gpsReciever;
final String GPS_FILTER = "MyGPSLocation";
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.textlayout);
initGpsListeners()
}
- initGpsListeners method initializes the necessary services and the recievers.
private void initGpsListeners() {
myGpsService = new
Intent(this, GpsService.class);
startService(myGpsService);
String GPS_FILTER = getResources().getString(GPS_FILTER);
IntentFilter mainFilter = new
IntentFilter(GPS_FILTER);
gpsReciever = new
MainGpsReciever();
registerReceiver(gpsReciever,
mainFilter);
}
private class MainGpsReciever extends
BroadcastReceiver {
public void
onReceive(Context arg0, Intent calledIntent) {
Constants.GPSLatitude =
calledIntent.getDoubleExtra("latitude",
-1);
Constants.GPSLongitude =
calledIntent.getDoubleExtra("longitude",
-1);
Constants.GPSSpeed =
calledIntent.getFloatExtra("speed",
-1);
Log.i("GPS
Demo", "Lat
& Long --- "+Constants.GPSLatitude+"--"+Constants.GPSLongitude);
Log.i("GPS
Demo", Speed ---
"+Constants.GPSSpeed);
//
}
}
}
This is the service class in its entirety.
public class
GpsService extends Service {
String GPS_FILTER = "";
Thread triggerService;
LocationManager lm;
GpsListener gpsLocationListener;
boolean isRunning = true;
@Override
public void
onCreate() {
// TODO
Auto-generated method stub
super.onCreate();
GPS_FILTER =
“MyGPSLocation”;
}
@Override
public void
onStart(Intent intent, int startId) {
// TODO
Auto-generated method stub
super.onStart(intent,
startId);
triggerService = new
Thread(new Runnable(){
public void
run(){
try{
Looper.prepare();//Initialize
the current thread as a looper.
lm =
(LocationManager)getSystemService(Context.LOCATION_SERVICE);
gpsLocationListener = new
GpsListener();
long
minTime = 30000; // 5 sec...
float
minDistance = 10;
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER,
minTime,
minDistance,
gpsLocationListener);
Looper.loop();
}catch(Exception
ex){
System.out.println("Exception
in triggerService Thread -- "+ex);
}
}
}, "myLocationThread");
triggerService.start();
}
@Override
public void
onDestroy() {
// TODO
Auto-generated method stub
super.onDestroy();
removeGpsListener();
}
@Override
public
IBinder onBind(Intent intent) {
// TODO
Auto-generated method stub
return null;
}
private void removeGpsListener(){
try{
lm.removeUpdates(gpsLocationListener);
}
catch(Exception
ex){
System.out.println("Exception
in GPSService --- "+ex);
}
}
class
GpsListener implements
LocationListener{
public void
onLocationChanged(Location location) {
// TODO
Auto-generated method stub
double
latitude = location.getLatitude();
double
longitude = location.getLongitude();
float
speed = location.getSpeed();
Intent filterRes = new
Intent(GPS_FILTER);
filterRes.putExtra("latitude",
latitude);
filterRes.putExtra("longitude",
longitude);
filterRes.putExtra("speed",
speed);
sendBroadcast(filterRes);
}
public void
onProviderDisabled(String provider) {
// TODO
Auto-generated method stub
}
public void
onProviderEnabled(String provider) {
// TODO
Auto-generated method stub
}
public void
onStatusChanged(String provider, int status, Bundle
extras) {
// TODO
Auto-generated method stub
}
}
}
