title: Android: NullPointerException at DialogFragment.dismissInternal at DialogFragment.dismissAllow
body: <p>Crash app when show ProgressDialog. I'm testing on my phone with a slide-out keyboard. When dialog is show I slide keyboard and app crashes.</p>
  
  <pre><code>public static class ProgressDialogFragment extends DialogFragment
  {
  
      public ProgressDialogFragment()
      {
          super();
      }
  
      @Override
      public Dialog onCreateDialog(Bundle savedInstanceState)
      {
          final ProgressDialog dialog = new ProgressDialog(getActivity());
          dialog.setMessage(getString(R.string.dlg_progress_title));
          dialog.setIndeterminate(true);
          dialog.setCancelable(false);
          return dialog;
      }
  
      @Override
      public void show(FragmentManager manager, String tag)
      {
          try
          {
              super.show(manager, tag);
          }
          catch (IllegalStateException e)
          {
              Log.d(TAG, e.getMessage());
          }
      }
  
  }
  </code></pre>
  
  <p>Crash log:</p>
  
  <pre><code>&gt; 04-25 20:49:46.999: E/AndroidRuntime(7904): FATAL EXCEPTION: main
  04-25 20:49:46.999: E/AndroidRuntime(7904): java.lang.NullPointerException
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.support.v4.app.DialogFragment.dismissInternal(DialogFragment.java:184)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.support.v4.app.DialogFragment.dismissAllowingStateLoss(DialogFragment.java:165)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at com.fisherman.activity.HomeActivity$2.onPostExecute(HomeActivity.java:268)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at com.fisherman.activity.HomeActivity$2.onPostExecute(HomeActivity.java:1)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.os.AsyncTask.finish(AsyncTask.java:417)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.os.AsyncTask.access$300(AsyncTask.java:127)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.os.Handler.dispatchMessage(Handler.java:99)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.os.Looper.loop(Looper.java:130)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at android.app.ActivityThread.main(ActivityThread.java:3835)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at java.lang.reflect.Method.invokeNative(Native Method)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at java.lang.reflect.Method.invoke(Method.java:507)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
  04-25 20:49:46.999: E/AndroidRuntime(7904):     at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>I've done class is static because app crash:</p>
  
  <pre><code>&gt; 04-25 20:48:50.757: E/AndroidRuntime(7863): Caused by: android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment com.fisherman.activity.HomeActivity$ProgressDialogFragment: make sure class name exists, is public, and has an empty constructor that is public
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.support.v4.app.Fragment.instantiate(Fragment.java:405)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.support.v4.app.FragmentState.instantiate(Fragment.java:97)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.support.v4.app.FragmentManagerImpl.restoreAllState(FragmentManager.java:1767)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:208)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at com.fisherman.activity.HomeActivity.onCreate(HomeActivity.java:50)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     ... 12 more
  04-25 20:48:50.757: E/AndroidRuntime(7863): Caused by: java.lang.InstantiationException: com.fisherman.activity.HomeActivity$ProgressDialogFragment
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at java.lang.Class.newInstanceImpl(Native Method)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at java.lang.Class.newInstance(Class.java:1409)
  04-25 20:48:50.757: E/AndroidRuntime(7863):     at android.support.v4.app.Fragment.instantiate(Fragment.java:394)
  </code></pre>