title: Why does my alert dialog crash
body: <p>recently I followed a tutorial on how to create an alert dialog and when i click on delete button, it should show me an alert before deleting but it crashed instead. Can someone tell me where my error lies?</p>
  
  <p>Below is my code:</p>
  
  <pre><code>// Delete button click event
      btnDeleteEvent.setOnClickListener(new View.OnClickListener() {
  
          public void onClick(View arg0) {
              // alerting user before deleting event
              AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
                      getApplicationContext());
              // set title
              alertDialogBuilder.setTitle("Warning!");
              // set dialog message
              alertDialogBuilder
                      .setMessage("Are you sure to delete event?")
                      .setCancelable(false)
                      .setPositiveButton("Yes",
                              new DialogInterface.OnClickListener() {
                                  public void onClick(DialogInterface dialog,
                                          int id) {
                                      // if yes, deleting event in background
                                      // thread
                                      new DeleteEvent().execute();
                                  }
                              })
                      .setNegativeButton("No",
                              new DialogInterface.OnClickListener() {
                                  public void onClick(DialogInterface dialog,
                                          int id) {
                                      // if this button is clicked, just close
                                      // the dialog box and do nothing
                                      dialog.cancel();
                                  }
                              });
  
              // create alert dialog
              AlertDialog alertDialog = alertDialogBuilder.create();
  
              // show it
              alertDialog.show();
          }
      });
  </code></pre>
  
  <p>Here is my logcat:</p>
  
  <pre><code>08-18 02:02:45.804: E/AndroidRuntime(1288): FATAL EXCEPTION: main
  08-18 02:02:45.804: E/AndroidRuntime(1288): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.view.ViewRoot.setView(ViewRoot.java:509)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.app.Dialog.show(Dialog.java:241)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at com.stts.sparetimetradingsystem.employer.EditEventActivity$5.onClick(EditEventActivity.java:270)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.view.View.performClick(View.java:2408)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.view.View$PerformClick.run(View.java:8816)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.os.Handler.handleCallback(Handler.java:587)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.os.Handler.dispatchMessage(Handler.java:92)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.os.Looper.loop(Looper.java:123)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at android.app.ActivityThread.main(ActivityThread.java:4627)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at java.lang.reflect.Method.invokeNative(Native Method)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at java.lang.reflect.Method.invoke(Method.java:521)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
  08-18 02:02:45.804: E/AndroidRuntime(1288):     at dalvik.system.NativeStart.main(Native Method)
  </code></pre>