Android - Gps Standort Änderung Entfernung

Question

Ich versuche, eine Tachometer-App, die Ort alle 5 Sekunden Intervall bekommen wird. Berechnen Sie die Entfernung und erhalten Sie die Geschwindigkeit des Benutzers, aber meine anfänglichen Daten zeigen einen hohen Wert zuerst ohne sogar das Telefon zu bewegen und dann als eine Art zufälliger Wert. Bitte überprüfe meinen Code.

MainActivity.java

public class MainActivity extends Activity { 


     private static final int REQUEST_CODE_PERMISSION = 2; 
     String mPermission = Manifest.permission.ACCESS_FINE_LOCATION; 

     TextView tvRunning, tvMax; 
     int maxv = 0; 
     // GPSTracker class 
     GPSTracker gps; 
     GPSTracker GPSTrackerBefore = new GPSTracker(MainActivity.this); 

     @Override 
     public void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_main); 

      tvRunning = (TextView) findViewById(R.id.tvRunnung); 
      tvMax = (TextView) fin 

dViewById(R.id.tvMax); 
     try { 
      if (ActivityCompat.checkSelfPermission(this, mPermission) 
        != MockPackageManager.PERMISSION_GRANTED) { 

       ActivityCompat.requestPermissions(this, new String[]{mPermission}, 
         REQUEST_CODE_PERMISSION); 

       // If any permission above not allowed by user, this condition will 
       //execute every time,else your else part will work 
      } 
     } catch (Exception e) { 

      e.printStackTrace(); 
     } 
     //----------------initializing the first gps----------------// 
     if(GPSTrackerBefore.canGetLocation){ 
      GPSTrackerBefore.getLocation(); 
     } 

     final Handler ha = new Handler(); 
     ha.postDelayed(new Runnable() { 

      @Override 
      public void run() { 
       //call function 
[enter image description here][1] 

       gps = new GPSTracker(MainActivity.this); 

       // check if GPS enabled 
       if (gps.canGetLocation()) { 

        double lon2 = gps.getLongitude(), lat2 = gps.getLatitude(); 
        double lon1 = GPSTrackerBefore.getLongitude(), lat1 = GPSTrackerBefore.getLatitude(); 

        int R = 6371; // km 
        double x = (lon2 - lon1) * Math.cos((lat1 + lat2)/2); 
        double y = (lat2 - lat1); 
        int d = (int) Math.sqrt(x * x + y * y) * R; 
        int v=d/5; //this is the velocity divided by interval time 
        Toast.makeText(getApplicationContext(), String.valueOf(v), Toast.LENGTH_SHORT).show(); 
//     Toast.makeText(getApplicationContext(), 
//       gps.getLatitude()+"||"+gps.getLongitude()+ 
//         "\n"+GPSTrackerBefore.getLatitude()+"||"+GPSTrackerBefore.getLongitude(), 
//          Toast.LENGTH_SHORT).show(); 
        GPSTrackerBefore = gps; 

        tvRunning.setText(String.valueOf(v)); 
        if (v > maxv) { 
         maxv = v; 
         tvMax.setText(String.valueOf(maxv)); 
        } 

       } else { 
        // can't get location 
        // GPS or Network is not enabled 
        // Ask user to enable GPS/network in settings 
        gps.showSettingsAlert(); 
       } 

       ha.postDelayed(this, 5000); 
      } 
     }, 5000); 


    } 

} 

GPSTracker.java

package bytebiters.com.speedo; 


public class GPSTracker extends Service implements LocationListener { 

    private final Context mContext; 

    // flag for GPS status 
    boolean isGPSEnabled = false; 

    // flag for network status 
    boolean isNetworkEnabled = false; 

    // flag for GPS status 
    boolean canGetLocation = false; 

    Location location; // location 
    double latitude; // latitude 
    double longitude; // longitude 

    // The minimum distance to change Updates in meters 
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 1 meters 

    // The minimum time between updates in milliseconds 
    private static final long MIN_TIME_BW_UPDATES = 3000 ; // 1 sec 

    // Declaring a Location Manager 
    protected LocationManager locationManager; 

    public GPSTracker(Context context) { 
     this.mContext = context; 
     getLocation(); 
    } 

    public Location getLocation() { 
     try { 
      locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE); 

      // getting GPS status 
      isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER); 

      // getting network status 
      isNetworkEnabled = locationManager 
        .isProviderEnabled(LocationManager.NETWORK_PROVIDER); 

      if (!isGPSEnabled && !isNetworkEnabled) { 
       // no network provider is enabled 
      } else { 
       this.canGetLocation = true; 
       // First get location from Network Provider 
       if (isNetworkEnabled) { 
        locationManager.requestLocationUpdates(
          LocationManager.NETWORK_PROVIDER, 
          MIN_TIME_BW_UPDATES, 
          MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 

        Log.d("Network", "Network"); 
        if (locationManager != null) { 
         location = locationManager 
           .getLastKnownLocation(LocationManager.NETWORK_PROVIDER); 

         if (location != null) { 
          latitude = location.getLatitude(); 
          longitude = location.getLongitude(); 
         } 
        } 
       } 

       // if GPS Enabled get lat/long using GPS Services 
       if (isGPSEnabled) { 
        if (location == null) { 
         locationManager.requestLocationUpdates(
           LocationManager.GPS_PROVIDER, 
           MIN_TIME_BW_UPDATES, 
           MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 

         Log.d("GPS Enabled", "GPS Enabled"); 
         if (locationManager != null) { 
          location = locationManager 
            .getLastKnownLocation(LocationManager.GPS_PROVIDER); 

          if (location != null) { 
           latitude = location.getLatitude(); 
           longitude = location.getLongitude(); 
          } 
         } 
        } 
       } 
      } 

     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

     return location; 
    } 

    /** 
    * Stop using GPS listener 
    * Calling this function will stop using GPS in your app 
    * */ 

    public void stopUsingGPS(){ 
     if(locationManager != null){ 
      locationManager.removeUpdates(GPSTracker.this); 
     } 
    } 

    /** 
    * Function to get latitude 
    * */ 

    public double getLatitude(){ 
     if(location != null){ 
      latitude = location.getLatitude(); 
     } 

     // return latitude 
     return latitude; 
    } 

    /** 
    * Function to get longitude 
    * */ 

    public double getLongitude(){ 
     if(location != null){ 
      longitude = location.getLongitude(); 
     } 

     // return longitude 
     return longitude; 
    } 

    /** 
    * Function to check GPS/wifi enabled 
    * @return boolean 
    * */ 

    public boolean canGetLocation() { 
     return this.canGetLocation; 
    } 

    /** 
    * Function to show settings alert dialog 
    * On pressing Settings button will lauch Settings Options 
    * */ 

    public void showSettingsAlert(){ 
     AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext); 

     // Setting Dialog Title 
     alertDialog.setTitle("GPS is settings"); 

     // Setting Dialog Message 
     alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?"); 

     // On pressing Settings button 
     alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog,int which) { 
       Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS); 
       mContext.startActivity(intent); 
      } 
     }); 

     // on pressing cancel button 
     alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog, int which) { 
       dialog.cancel(); 
      } 
     }); 

     // Showing Alert Message 
     alertDialog.show(); 
    } 

    @Override 
    public void onLocationChanged(Location location) { 
    } 

    @Override 
    public void onProviderDisabled(String provider) { 
    } 

    @Override 
    public void onProviderEnabled(String provider) { 
    } 

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

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

Answer 1

In GPSTracker, versuchen, Breite oder Länge zu lesen 0 zurück, wenn kein Standort verfügbar ist. Sie benötigen mehrere Messwerte, bevor Sie versuchen, die Geschwindigkeit mithilfe Ihrer Methode zu schätzen.

Code beiseite, GPS-Koordinaten sind inhärent laut (die Position ist nicht genau bekannt). Bei einer Geschwindigkeitsmessung, die auf Rauschen in der Positionsschätzung zurückzuführen ist, wird es immer Fehler geben. Es gibt ausgeklügeltere Verfahren zum Abschätzen von Geschwindigkeit und Ort von verrauschten Messungen, wie zum Beispiel Kalman Filter.