Android - AlertDialog() сбой

Question

Я получаю эту ошибку, когда я запускаю свой проект. Я искал, и я думаю, что проблема имеет какое-то отношение к контексту, но я не знаю, как его решить.

Мой код: (я думаю, что ошибка в методе showSettingsAlert())

public class GPSTracker extends Service implements LocationListener { 

private final Context mContext; 

private TextView textView; 


// 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 = 1000; // 1000 meters 

// The minimum time between updates in milliseconds 
private static final long MIN_TIME_BW_UPDATES = 60000 * 60 * 1; // 60 minute 

// Declaring a Location Manager 
protected LocationManager locationManager; 

@Override 
public int onStartCommand(Intent intent, int flags, int startId) { 
    getLocation(); 
    return START_STICKY; 
} 

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(); 
    } 
    stopUsingGPS(); 
    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) { 
    textView.append("\n "+location.getLatitude()+" "+location.getLongitude()); 
} 

@Override 
public void onProviderDisabled(String provider) { 
    Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS); 
    mContext.startActivity(intent); 
} 

@Override 
public void onProviderEnabled(String provider) { 
} 

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

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

} 

Вот мой Logcat:

10-25 20:29:30.277 10524-10524/com.example.nunog.myapplication12 E/AndroidRuntime: FATAL EXCEPTION: main 
                       Process: com.example.nunog.myapplication12, PID: 10524 
                       java.lang.RuntimeException: Unable to start service com.example.nunog.myapplication12.Anomaly@424d1620 with Intent { cmp=com.example.nunog.myapplication12/.Anomaly (has extras) }: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application 
                        at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3006) 
                        at android.app.ActivityThread.access$2200(ActivityThread.java:174) 
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1404) 
                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                        at android.os.Looper.loop(Looper.java:146) 
                        at android.app.ActivityThread.main(ActivityThread.java:5593) 
                        at java.lang.reflect.Method.invokeNative(Native Method) 
                        at java.lang.reflect.Method.invoke(Method.java:515) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
                        at dalvik.system.NativeStart.main(Native Method) 
                       Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application 
                        at android.view.ViewRootImpl.setView(ViewRootImpl.java:775) 
                        at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:278) 
                        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69) 
                        at android.app.Dialog.show(Dialog.java:301) 
                        at android.app.AlertDialog$Builder.show(AlertDialog.java:957) 
                        at com.example.nunog.myapplication12.GPSTracker.showSettingsAlert(GPSTracker.java:176) 

EDIT: Я уже попробовать использовать этот вместо mContext в моем AlertDialog(), но когда я это делаю, я получаю исключение NullPointerException ,

Answer 1

Ваш mContext имеет нулевое значение, использование активность показать alertDialog, а не в службе, служба является фоновая задача, она не может работать с UI

Answer 2

Вы можете только создать диалог оповещения с помощью процесса, как Bobbake4 уже прокомментировал.

Другой ответ может быть, может помочь вам: https://stackoverflow.com/a/22627480/2972104

Answer 3

Создать конструктор вашего класса и передать контекст деятельности

private Context mContext; 

public GPSTracker(Context context) { 
     mContext = context; 
} 

объекта Make в своем классе, как этот

GPSTracker tracker = new GPSTracker(YourActivity.this);