Window manager bad token exception

Question

Hi I am facing a problem in Message dialog, getting Force close my code is here.

in on create:

  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.email_result);

    email_result = (Button) findViewById(R.id.email_result_btn);
    email_result.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            if (diffdays > 365) {

                h.sendEmptyMessage(0);
              }
         }
     }
  }

My Handler:

private Handler h = new Handler() {
    public void handleMessage(Message msg) {
           showMessageDialog("Sorry, you cannot email entries which are earlier than one year ago.");
    }
};

ShowMessageDialog Method:

public void showMessageDialog(String nMessage) {

    alertDialog = new Dialog(Email_Result.this);
    AlertDialog.Builder customBuilder = new AlertDialog.Builder(
            Email_Result.this);
    customBuilder.setMessage(nMessage);
    customBuilder.setPositiveButton(getString(R.string.ok),
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    alertDialog.dismiss();
                }
            });
    alertDialog = customBuilder.create();
    alertDialog.setCancelable(true);
    alertDialog.show();
}

Error Log

01-11 12:08:24.470: ERROR/AndroidRuntime(325): FATAL EXCEPTION: main
01-11 12:08:24.470: ERROR/AndroidRuntime(325): android.view.WindowManager$BadTokenException: Unable to add window -- token android.app.LocalActivityManager$LocalActivityRecord@44f1dfd8 is not valid; is your activity running?
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.view.ViewRoot.setView(ViewRoot.java:505)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.view.Window$LocalWindowManager.addView(Window.java:424)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.app.Dialog.show(Dialog.java:241)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at com.stress1.Email_Result.showMessageDialog(Email_Result.java:207)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at com.stress1.Email_Result$2.onClick(Email_Result.java:81)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.view.View.performClick(View.java:2408)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.view.View$PerformClick.run(View.java:8816)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.os.Handler.handleCallback(Handler.java:587)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.os.Looper.loop(Looper.java:123)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at android.app.ActivityThread.main(ActivityThread.java:4627)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at java.lang.reflect.Method.invokeNative(Native Method)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at java.lang.reflect.Method.invoke(Method.java:521)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-11 12:08:24.470: ERROR/AndroidRuntime(325):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

It seems like the Exception occurs when you invoke the show() method on the Dialog. Try using the following code which might circumvent your problem:

 try {
      alertDialog.show();
 } catch(Exception e){
   // WindowManager$BadTokenException will be caught and the app would not display 
   // the 'Force Close' message
 }

Such a problem arises when the activity is trying to display an AlertDialog after it has already been terminated. So, you might want to look closely at how your code works.

Also, your showMessageDialog method could be simplified as follows:

public void showMessageDialog(String nMessage) {

    AlertDialog.Builder customBuilder = new AlertDialog.Builder(Email_Result.this);
    customBuilder.setMessage(nMessage);
    customBuilder.setPositiveButton(getString(R.string.ok),new DialogInterface.OnClickListener(){
         @Override            
         public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
         }
    });
    customBuilder.setCancelable(true);
    customBuilder.show();
}