title: Window manager bad token exception
body: <p>Hi I am facing a problem in Message dialog, getting Force close my code is here.</p>
  
  <p>in on create:</p>
  
  <pre><code>  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 &gt; 365) {
  
                  h.sendEmptyMessage(0);
                }
           }
       }
    }
  </code></pre>
  
  <p>My Handler:</p>
  
  <pre><code>private Handler h = new Handler() {
      public void handleMessage(Message msg) {
             showMessageDialog("Sorry, you cannot email entries which are earlier than one year ago.");
      }
  };
  </code></pre>
  
  <p>ShowMessageDialog Method:</p>
  
  <pre><code>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();
  }
  </code></pre>
  
  <p>Error Log</p>
  
  <pre><code>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)
  </code></pre>