GPS緯度，一次又一次改變當前位置

我試圖找到設備的速度。我正在使用速度公式來獲得每一個好的。但我有一個問題。我得到了不同的拉特，如果我把手機放在同一個地方，然後幾秒鐘後它的位置變化，速度，距離等，我想如果設備不在運行，那麼它只顯示一個當前拉特，長（速度= 0）沒有不同，因爲位置不變。我使用這個類：GPS緯度，一次又一次改變當前位置

public class GPSTracker extends Service implements LocationListener 
{ 
boolean first_time=true; 
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 

double prev_lat=0.0; 
double prev_long=0.0; 
// The minimum distance to change Updates in meters 
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 0;// meters (make the time and distance to 0,0 so that we could get the updates very quickly 
// The minimum time between updates in milliseconds 
private static final long MIN_TIME_BW_UPDATES = 0;//1000 * 60 * 1; // minute 

// Declaring a Location Manager 
protected LocationManager locationManager; 

int hour1=0; 
int minute1=0; 
int second1=0; 
int hour2=0; 
int minute2=0; 
int second2=0; 

int time_dif=0; 

private static float distance=0; 
static double speed=0; 

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) 
     { 
      Toast.makeText(getApplicationContext(), "Either Network or GPS is not available in your Mob " , Toast.LENGTH_LONG).show(); 
      // no network provider is enabled 
     } 
     else 
     { 
      this.canGetLocation = true; 

      // if GPS Enabled get lat/long using GPS Services 
      /*if (isNetworkEnabled)    
      { 
        //Update the location of a user after t time and d distance... where we have declared time and distance as 0,0 which means to get frequent updates. 
      locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 
         MIN_TIME_BW_UPDATES, 
         MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 

       if (locationManager != null) 
       { 
        location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER); 
        if (location != null) { 
         latitude = location.getLatitude(); 
         longitude = location.getLongitude(); 
         //Toast.makeText(getApplicationContext(), "Location "+location.getLatitude() , Toast.LENGTH_LONG).show(); 
        } 
       } 
      } 
      //*/ 
      //else if (isGPSEnabled) 
      if (isGPSEnabled) 
      { //Toast.makeText(getApplicationContext(), "inside 'isGpdenabled' " , Toast.LENGTH_LONG).show(); 
       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 settings"); 

    // Setting Dialog Message 
    alertDialog.setMessage("GPS is not enable. 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(); 
} 

//(((((Find distance between two geolocation ))) 
public float FindDistance(float lat1, float lng1, float lat2, float lng2) 
    { 
     double earthRadius = 6371000; //meters 
      double dLat = Math.toRadians(lat2-lat1); 
      double dLng = Math.toRadians(lng2-lng1); 
      double a = Math.sin(dLat/2) * Math.sin(dLat/2) + 
         Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) * 
         Math.sin(dLng/2) * Math.sin(dLng/2); 
      double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
      float dist = (float) (earthRadius * c); 

      return dist; 

    } 


public double Set_Speed_inKM() 
{ 
    speed=speed*3.6; // Formula to Convert M/Sec --> KM/Sec 

    return speed; 
} 

@Override 
public void onLocationChanged(Location location) 
{ 
    if(!first_time) 
    { 

    if(prev_lat!=location.getLatitude() & prev_long!=location.getLongitude()) 
    { 
    //showtoast("Location Changed"); 
    Calendar c = Calendar.getInstance(); 
    second1=c.get(Calendar.SECOND);  

    if(second2>second1) 
     second1=60+second1; 

     time_dif=second1-second2;  
     time_dif=Math.abs(time_dif); 


    second2=second1; 

    distance=FindDistance((float)prev_lat,(float)prev_long,(float)location.getLatitude(),(float)location.getLongitude()); 

    if(time_dif!=0) 
     speed=distance/time_dif; 

    Set_Speed_inKM(); 

     Log.e("LOCATION CHANGED", "data"+location.getLatitude()+"\n"); 

      //Calling Function and Passing Value 
      sendMessageToActivity(location ,time_dif,"NewLocation", this.mContext); 

      //prev_lat=location.getLatitude(); 
      // prev_long=location.getLongitude(); 

     } 
    } 
     prev_lat=location.getLatitude(); 
     prev_long=location.getLongitude(); 

     first_time=false; 
    } 


//(((This Function SEND data 2 ACTIVITY))))))) 
private static void sendMessageToActivity(Location l,float time_diff, String msg, Context c) 
{ 
    Intent intent = new Intent("GPSLocationUpdates"); 
    // You can also include some extra data. 
    intent.putExtra("Status", msg); 
    Bundle b = new Bundle(); 
    b.putParcelable("Location", l); 
    intent.putExtra("Location", b); 
    intent.putExtra("speed", ""+speed); 
    intent.putExtra("time_diff", ""+distance); 
    LocalBroadcastManager.getInstance(c).sendBroadcast(intent); 
} 


@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; 
} 

//Show-Toast Message 
public void showtoast(String str) 
{ 
// Toast.makeText(getApplicationContext(), str, Toast.LENGTH_LONG).show(); 
}

}

來源

2016-02-23 Pir Fahim Shah

我看到只有一個問題...您使用**非常糟糕的代碼從androidhive ** ...服務不需要上下文，因爲它是一個上下文本身...你也不能在服務派生類上調用新的運算符你的代碼......但是關於你所謂的問題：MIN_DISTANCE_CHANGE_FOR_UPDATES = 0 + GPS不準確導致「位置改變」的事實......你不應該爲此而煩惱，改變是非常小的（小於準確度的GPS）... – Selvin

@Selvin謝謝你，但請告訴我在哪裏改變代碼，請我真的被困在它 –

everthing ...但即使沒有這個不好的代碼...它會以同樣的方式工作...將MIN_DISTANCE_CHANGE_FOR_UPDATES更改爲至少5，然後您不應該更改... – Selvin

的GPS的精度不是絕對的，所以即使是靜態的設備會顯示在連續讀數不同的位置。通過讀取加速度計 - 如果兩個讀數之間的差值大於某個閾值 - 設備正在移動，您可以添加一種方法來檢測手機是否靜止。如果它太小 - 它不會移動。要確定增量 - 將設備放在桌子上，看看你得到了什麼值。

來源

2016-02-23 12:46:57 TDG

GPS緯度，一次又一次改變當前位置

回答

相關問題