Question

i want to open or focus to my current location in google map in android. I want my app to get coordinates and then give the name of my location from these coordinates and also in the end focus the current location map…
Kindly someone suggest me what and how to do and if possible give me some code sample. i m new to android 🙂
Thanks in advance! 🙂

Answer 1

here is the example of simple map display with current location

MyMap.java for display map

class MyMap extends MapActivity{
/** Called when the activity is first created. */
GeoPoint defaultPoint;
static GeoPoint point;
static MapController mc;
static MapView mapView;
static double curLat =0;
static double curLng =0;

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    mapView = (MapView)findViewById(R.id.mapview);
    mapView.setBuiltInZoomControls(true);

    String coordinates[] = {"22.286595", "70.795685"};
    double lat = Double.parseDouble(coordinates[0]);
    double lng = Double.parseDouble(coordinates[1]);

    mc = mapView.getController();

    defaultPoint = new GeoPoint(
        (int) (lat * 1E6), 
        (int) (lng * 1E6));

    mc.animateTo(defaultPoint);
    mc.setZoom(13); 

    MapOverlay mapOverlay = new MapOverlay();
    List<Overlay> listOfOverlays = mapView.getOverlays();
    listOfOverlays.clear();
    listOfOverlays.add(mapOverlay);   

    mapView.invalidate();

    Intent startService = new Intent(getApplicationContext(),ServiceLocation.class);
    startService(startService);
}

public static void updateMap() {
    if(ServiceLocation.curLocation!=null){
        curLat = ServiceLocation.curLocation.getLatitude();
        curLng = ServiceLocation.curLocation.getLongitude();        
        if(mapView!=null){
            point = new GeoPoint((int)(curLat*1e6),(int)(curLng*1e6));
            mc.animateTo(point);
            mapView.invalidate();
        }
    }
}
@Override
protected boolean isRouteDisplayed(){
    return false;
}
class MapOverlay extends com.google.android.maps.Overlay{
    @Override
    public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) {
        super.draw(canvas, mapView, shadow);                   

        if(!shadow){
            //---translate the GeoPoint to screen pixels---
            Point screenPts = new Point();
            if(curLat==0 && curLng==0)
                mapView.getProjection().toPixels(defaultPoint, screenPts);
            else{
                mapView.getProjection().toPixels(point, screenPts);
            }
            //---add the marker---
            Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.cur_loc);            
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);
        }
        return true;
    }
}
}

here is my background service code for fetching lat/lng using gps

class ServiceLocation extends Service{
private LocationManager locMan;
private Boolean locationChanged;
private Handler handler = new Handler();

public static Location centerLoc;
public static Location curLocation;
public static boolean isService = true;


LocationListener gpsListener = new LocationListener() {
    public void onLocationChanged(Location location) {
        if (curLocation == null) {
            curLocation = location;
            locationChanged = true;
        }else if (curLocation.getLatitude() == location.getLatitude() && curLocation.getLongitude() == location.getLongitude()){
            locationChanged = false;
            return;
        }else
            locationChanged = true;

        curLocation = location;


        if (locationChanged)
            locMan.removeUpdates(gpsListener);


    MyMap.updateMap();
    }
    public void onProviderDisabled(String provider) {
    }

    public void onProviderEnabled(String provider) {
        // Log.w("GPS", "Location changed", null);
    }

    public void onStatusChanged(String provider, int status,Bundle extras) {
        if (status == 0)// UnAvailable
        {
        } else if (status == 1)// Trying to Connect
        {
        } else if (status == 2) {// Available
        }
    }

};

@Override
public void onCreate() {
    super.onCreate();
    if (locMan.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
       locMan.requestLocationUpdates(LocationManager.GPS_PROVIDER,100, 1, gpsListener);
    } else {
       this.startActivity(new Intent("android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS"));
    }
    centerLoc = new Location("");
    curLocation = locMan.getLastKnownLocation(LocationManager.GPS_PROVIDER);;*/
    centerLoc = new Location("");
    curLocation = getBestLocation();

    if (curLocation == null) 
        Toast.makeText(getBaseContext(),"Unable to get your location", Toast.LENGTH_SHORT).show();

    isService =  true;
}
final String TAG="LocationService";
   @Override
   public int onStartCommand(Intent intent, int flags, int startId) {
 return super.onStartCommand(intent, flags, startId);
   }



@Override
   public void onLowMemory() {
       super.onLowMemory();
   }

   @Override
   public void onStart(Intent i, int startId){
      handler.postDelayed(GpsFinder,5000);// will start after 5 seconds
   }

   @Override
   public void onDestroy() {
       handler.removeCallbacks(GpsFinder);
       handler = null;
       Toast.makeText(this, "Stop services", Toast.LENGTH_SHORT).show();
       isService = false;
   }

   public IBinder onBind(Intent arg0) {
         return null;
  }

  public Runnable GpsFinder = new Runnable(){
    public void run(){
        Location tempLoc = getBestLocation();
        if(tempLoc!=null)
            curLocation = tempLoc;
        handler.postDelayed(GpsFinder,5000);// register again to start after 5 seconds...        
    }
  };

    private Location getBestLocation() {        
        Location gpslocation = null;
        Location networkLocation = null;

        if(locMan==null)
              locMan = (LocationManager) getApplicationContext() .getSystemService(Context.LOCATION_SERVICE);
        try {
            if(locMan.isProviderEnabled(LocationManager.GPS_PROVIDER)){
                locMan.requestLocationUpdates(LocationManager.GPS_PROVIDER,100, 1, gpsListener);
                gpslocation = locMan.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            }
            if(locMan.isProviderEnabled(LocationManager.NETWORK_PROVIDER)){
                locMan.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,100, 1, gpsListener);
                networkLocation = locMan.getLastKnownLocation(LocationManager.NETWORK_PROVIDER); 
            }
        } catch (IllegalArgumentException e) {
            //Log.e(ErrorCode.ILLEGALARGUMENTERROR, e.toString());
            Log.e("error", e.toString());

        }
        if(gpslocation==null && networkLocation==null)
            return null;

        if(gpslocation!=null && networkLocation!=null){
            if(gpslocation.getTime() < networkLocation.getTime())
                return networkLocation;
            else
                return gpslocation;
        }
        if (gpslocation == null) {
            return networkLocation;
        }
        if (networkLocation == null) {
            return gpslocation;
        }
        return null;
    }
}