Calculer la distance restante à la programmation de destination android google map API V2?

Question

Je suis en train de montrer calculer la distance restante jusqu'à destination pour afficher à l'utilisateur avec le code ci-dessous:

public class MyService extends Service { 
    private LocationManager locManager; 
    private LocationListener locListener = new myLocationListener(); 
    static final Double EARTH_RADIUS = 6371.00; 

    private boolean gps_enabled = false; 
    private boolean network_enabled = false; 

    private Handler handler = new Handler(); 
    Thread t; 

    @Override 
    public IBinder onBind(Intent intent) { 
     return null; 
    } 

    @Override 
    public void onCreate() { 
    } 

    @Override 
    public void onDestroy() { 
    } 

    @Override 
    public void onStart(Intent intent, int startid) { 
    } 

    @Override 
    public int onStartCommand(Intent intent, int flags, int startId) { 

     Toast.makeText(getBaseContext(), "Service Started", Toast.LENGTH_SHORT).show(); 

     final Runnable r = new Runnable() { 
      public void run() { 
       Log.v("Debug", "Hello"); 
       location(); 
       handler.postDelayed(this, 5000); 
      } 
     }; 
     handler.postDelayed(r, 5000); 
     return START_STICKY; 
    } 

    public void location() { 
     locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 

     try { 
      gps_enabled = locManager.isProviderEnabled(LocationManager.GPS_PROVIDER); 
     } catch (Exception ex) { 
     } 
     try { 
      network_enabled = locManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER); 
     } catch (Exception ex) { 
     } 
     Log.v("Debug", "in on create.. 2"); 
     if (gps_enabled) { 
      if (ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
       // TODO: Consider calling 
       // ActivityCompat#requestPermissions 
       // here to request the missing permissions, and then overriding 
       // public void onRequestPermissionsResult(int requestCode, String[] permissions, 
       //           int[] grantResults) 
       // to handle the case where the user grants the permission. See the documentation 
       // for ActivityCompat#requestPermissions for more details. 
       return; 
      } 
      locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locListener); 
      Log.v("Debug", "Enabled.."); 
     } 
     if (network_enabled) { 
      locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener); 
      Log.v("Debug", "Disabled.."); 
     } 
     Log.v("Debug", "in on create..3"); 
    } 

    private class myLocationListener implements LocationListener { 
     double lat_old = 34.629678; 
     double lon_old = 50.860293; 
     double lat_new; 
     double lon_new; 
     double time = 10; 
     double speed = 0.0; 

     @Override 
     public void onLocationChanged(Location location) { 
      Log.v("Debug", "in onLocation changed.."); 
      if (location != null) { 
       if (ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
        return; 
       } 
       locManager.removeUpdates(locListener); 
       lat_new = location.getLongitude(); 
       lon_new = location.getLatitude(); 
       String longitude = "Longitude: " + location.getLongitude(); 
       String latitude = "Latitude: " + location.getLatitude(); 
       double distance = CalculationByDistance(lat_new, lon_new, lat_old, lon_old); 
       Toast.makeText(getApplicationContext(), longitude + "\n" + latitude + "\nDistance is: " 
         + distance , Toast.LENGTH_SHORT).show(); 
      } 
     } 

     @Override 
     public void onProviderDisabled(String provider) { 
     } 

     @Override 
     public void onProviderEnabled(String provider) { 
     } 

     @Override 
     public void onStatusChanged(String provider, int status, Bundle extras) { 
     } 
    } 

    public double CalculationByDistance(double lat1, double lon1, double lat2, double lon2) { 
     double Radius = EARTH_RADIUS; 
     double dLat = Math.toRadians(lat2 - lat1); 
     double dLon = Math.toRadians(lon2 - lon1); 
     double a = Math.sin(dLat/2) * Math.sin(dLat/2) + 
       Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) * 
         Math.sin(dLon/2) * Math.sin(dLon/2); 
     double c = 2 * Math.asin(Math.sqrt(a)); 
     return Radius * c; 
    } 
} 

Problème:

1- La valeur de distance ne change pas!

2- Et quand je me arrête je vois le Toast par 5000:

Toast.makeText(getApplicationContext(), longitude + "\n" + latitude + "\nDistance is: " + distance , Toast.LENGTH_SHORT).show();

Je ne ne devrait voir le pain grillé parce que je me sers onLocationChanged!

Je ne vois pas de pain grillé lorsque je m'arrête.

Answer 1

Essayez d'utiliser distanceTo méthode

Location locationOne = new Location("point First"); 

locationOne.setLatitude(latA); 

locationOne.setLongitude(lngA); 

Location locationTwo = new Location("point Second"); 

locationTwo.setLatitude(latB); 

locationTwo.setLongitude(lngB); 

float distance = locationOne.distanceTo(locationTwo);