title: Runtime Exception AlertDialog in Android
body: <p>I trying to execute the following code... but the AlertDialog is creating problems! Without that the code works fine. I want a dialogbox to pop up and ask the user to enable GPS when its turned off!</p>
  
  <pre><code>public class Testing extends Service {
      private Location loc;
      private Dialog dialog;
      String DATA;
      @Override
      public IBinder onBind(Intent arg0) {
          // TODO Auto-generated method stub
          return null;
      }
      @Override
      public void onCreate()
      {       
              super.onCreate();
      }
      @Override
      public void onStart(Intent intent, int startId) 
      {
          LocationManager LM = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
          if (!LM.isProviderEnabled(LocationManager.GPS_PROVIDER)){ 
              AlertDialog.Builder builder = new AlertDialog.Builder(this);
              builder.setMessage("Your GPS is disabled! Would you like to enable it?")
                      .setCancelable(false).setPositiveButton("Enable GPS",
                              new DialogInterface.OnClickListener() {
                                  public void onClick(DialogInterface dialog, int id) {
                                      Intent gpsOptionsIntent = new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                                      startActivity(gpsOptionsIntent);
                                  }
                              });
              builder.setNegativeButton("Do nothing",
                      new DialogInterface.OnClickListener() {
                          public void onClick(DialogInterface dialog, int id) {
                              dialog.cancel();
                          }
                      });
              AlertDialog alert = builder.create();
              alert.show();
          }
          LocationListener LL = new MyLocationListener();
          LM.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 0, LL);
          LM.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, LL);
         /*//Runnable to determine when the first GPS fix was received.
          Runnable showWaitDialog = new Runnable() {
              @Override
              public void run() {
              while (loc == null) {
              // Wait for first GPS Fix (do nothing until loc != null)
              }
              // After receiving first GPS Fix dismiss the Progress Dialog
              dialog.dismiss();
              }
              };
              // Create a Dialog to let the User know that we're waiting for a GPS Fix
              dialog = ProgressDialog.show(getApplicationContext(), "Please wait...","Retrieving GPS data ...", true);
              Thread t = new Thread(showWaitDialog);
              t.start();*/
          LM.addNmeaListener(new NmeaListener() {
          public void onNmeaReceived(long timestamp, String nmea) 
          { 
                      DATA = nmea;
          }});
      }
  </code></pre>
  
  <p>But I am getting this error! The ProgressDialog code within the comment lines also throws the same error!</p>
  
  <pre><code>08-04 04:36:09.664: ERROR/AndroidRuntime(6301): FATAL EXCEPTION: main
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301): java.lang.RuntimeException: Unable to start service Firstdroid.Gps.Testing@462a35d0 with Intent { cmp=Firstdroid.Gps/.Testing }: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3282)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.ActivityThread.access$3600(ActivityThread.java:135)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2211)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.os.Handler.dispatchMessage(Handler.java:99)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.os.Looper.loop(Looper.java:144)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.ActivityThread.main(ActivityThread.java:4937)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at java.lang.reflect.Method.invokeNative(Native Method)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at java.lang.reflect.Method.invoke(Method.java:521)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at dalvik.system.NativeStart.main(Native Method)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301): Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.view.ViewRoot.setView(ViewRoot.java:513)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.Dialog.show(Dialog.java:241)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at Firstdroid.Gps.UrbanExplorer.onStart(UrbanExplorer.java:84)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.Service.onStartCommand(Service.java:420)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3267)
  08-04 04:36:09.664: ERROR/AndroidRuntime(6301):     ... 10 more
  </code></pre>