title: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
body: <p>I'm using the support library for my app. In my FragmentActivity I'm using an AsyncTask for downloading data from internet. In the onPreExecute() method I add a Fragment and in the onPostExecute() method I remove it again. When the orientation is changed in between, I get the above mentioned exception. Please take a look at the details:</p>
  
  <pre><code>private class onFriendAddedAsyncTask extends AsyncTask&lt;String, Void, String&gt; {
      DummyFragment dummyFragment; 
      FragmentManager fm;
      FragmentTransaction ft;
  
  @Override
  protected void onPreExecute() {
      Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute");
      dummyFragment = DummyFragment.newInstance();
      fm = getSupportFragmentManager();
      ft = fm.beginTransaction();
      ft.add(dummyFragment, "dummy_fragment");
      ft.commit();
  }
  
  @Override
  protected void onPostExecute(String result) {
      Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute");
      ft = fm.beginTransaction();
      ft.remove(dummyFragment);
      ft.commit();
  }
  
  @Override
  protected String doInBackground(String... name) {
      Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/doInBackground");
      ...
  }
  </code></pre>
  
  <p>I get following LogCut:</p>
  
  <pre><code>01-05 23:54:19.958: V/MyFragmentActivity(12783): onFriendAddedAsyncTask/onPreExecute
  01-05 23:54:19.968: V/DummyFragment(12783): onAttach
  01-05 23:54:19.968: V/DummyFragment(12783): onCreate
  01-05 23:54:19.968: V/MyFragmentActivity(12783): onFriendAddedAsyncTask/doInBackground
  01-05 23:54:19.973: V/DummyFragment(12783): onCreateView
  01-05 23:54:19.973: V/DummyFragment(12783): onActivityCreated
  01-05 23:54:19.973: V/DummyFragment(12783): onStart
  01-05 23:54:19.973: V/DummyFragment(12783): onResume
  01-05 23:54:21.933: V/MyFragmentActivity(12783): onSaveInstanceState
  01-05 23:54:21.933: V/DummyFragment(12783): onSaveInstanceState
  01-05 23:54:21.933: V/MyFragmentActivity(12783): onPause
  01-05 23:54:21.933: V/DummyFragment(12783): onPause
  01-05 23:54:21.938: V/MyFragmentActivity(12783): onStop
  01-05 23:54:21.938: V/DummyFragment(12783): onStop
  01-05 23:54:21.938: V/MyFragmentActivity(12783): onDestroy
  01-05 23:54:21.938: V/DummyFragment(12783): onDestroyView
  01-05 23:54:21.938: V/DummyFragment(12783): onDestroy
  01-05 23:54:21.938: V/DummyFragment(12783): onDetach
  01-05 23:54:21.978: V/MyFragmentActivity(12783): onCreate
  01-05 23:54:21.978: V/DummyFragment(12783): onAttach
  01-05 23:54:21.978: V/DummyFragment(12783): onCreate
  01-05 23:54:22.263: V/MyFragmentActivity(12783): onStart
  01-05 23:54:22.313: V/DummyFragment(12783): onCreateView
  01-05 23:54:22.313: V/DummyFragment(12783): onActivityCreated
  01-05 23:54:22.313: V/DummyFragment(12783): onStart
  01-05 23:54:22.323: V/MyFragmentActivity(12783): onResume
  01-05 23:54:22.323: V/MyFragmentActivity(12783): onPostResume
  01-05 23:54:22.323: V/MyFragmentActivity(12783): onResumeFragments
  01-05 23:54:22.323: V/DummyFragment(12783): onResume
  01-05 23:54:27.123: V/MyFragmentActivity(12783): onFriendAddedAsyncTask/onPostExecute
  01-05 23:54:27.123: D/AndroidRuntime(12783): Shutting down VM
  01-05 23:54:27.123: W/dalvikvm(12783): threadid=1: thread exiting with uncaught exception (group=0x4001d7d0)
  01-05 23:54:27.138: E/AndroidRuntime(12783): FATAL EXCEPTION: main
  01-05 23:54:27.138: E/AndroidRuntime(12783): java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1314)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1325)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:548)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:532)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at com.xyz.dummy.MyFragmentActivity$onFriendAddedAsyncTask.onPostExecute(MyFragmentActivity.java:447)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at com.xyz.dummy.MyFragmentActivity$onFriendAddedAsyncTask.onPostExecute(MyFragmentActivity.java:1)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.os.AsyncTask.finish(AsyncTask.java:417)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.os.AsyncTask.access$300(AsyncTask.java:127)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.os.Handler.dispatchMessage(Handler.java:99)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.os.Looper.loop(Looper.java:123)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at android.app.ActivityThread.main(ActivityThread.java:4627)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at java.lang.reflect.Method.invokeNative(Native Method)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at java.lang.reflect.Method.invoke(Method.java:521)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  01-05 23:54:27.138: E/AndroidRuntime(12783):    at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>In other threads about similar problems the reason seems to be that the onPostExecute method is called before the onResume() method is called. But I get the exception even though onResume() is called before.</p>
  
  <p>Does someone knows what's wrong?</p>
  
  <p>The Activity looks like this:</p>
  
  <pre><code>public class MyFragmentActivity extends FragmentActivity implements OnFriendSelectedListener, OnFriendAddedListener, OnFriendOptionSelectedListener, LoaderCallbacks&lt;Cursor&gt; {
  
  @Override
  public void onCreate(Bundle savedInstanceState) {
      Log.v("MyFragmentActivity", "onCreate");
      super.onCreate(savedInstanceState);
      setContentView(R.layout.fragment_activity_layout);
      FragmentManager fm = getSupportFragmentManager();
      FragmentTransaction ft = fm.beginTransaction();
      FriendListFragment friendListFragment = (FriendListFragment)fm.findFragmentById(R.id.friend_list_fragment_layout);
      if (friendListFragment == null) {
          friendListFragment = new FriendListFragment(); 
          ft.add(R.id.friend_list_fragment_layout, friendListFragment);
          ft.commit();
          fm.executePendingTransactions();
          startService(new Intent(this, MyIntentService.class));
          getSupportLoaderManager().initLoader(CHECK_EMPTY_DATABASE, null, this);
      }
  }
  
      @Override
  public boolean onCreateOptionsMenu(Menu menu) {
      super.onCreateOptionsMenu(menu);
      getMenuInflater().inflate(R.menu.fragment_activity_options_menu, menu);
      return true;
  }
  
  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
      super.onOptionsItemSelected(item);
      switch (item.getItemId()) {
      case R.id.add_friend_menu_item:
          AddFriendDialogFragment addFriendDialogFragment = AddFriendDialogFragment.newInstance();
          addFriendDialogFragment.show(getSupportFragmentManager(), "add_friend_dialog_fragment");
          return true;
      default:
          return false;
      }
  }
  
  @Override
  public void onFriendAdded(String name) {
      name = name.trim();
      if (name.length() &gt; 0) {
          new onFriendAddedAsyncTask().execute(name);
      }
  }
  </code></pre>
  
  <p>When using commitAllowingStateLoss() I get the following exception:</p>
  
  <pre><code>01-06 14:54:29.548: E/AndroidRuntime(18020): FATAL EXCEPTION: main
  01-06 14:54:29.548: E/AndroidRuntime(18020): java.lang.IllegalStateException: Activity has been destroyed
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1329)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:548)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:536)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at com.xyz.dummy.FadiaFragmentActivity$onFriendAddedAsyncTask.onPostExecute(FadiaFragmentActivity.java:461)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at com.xyz.dummy.FadiaFragmentActivity$onFriendAddedAsyncTask.onPostExecute(FadiaFragmentActivity.java:1)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.os.AsyncTask.finish(AsyncTask.java:417)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.os.AsyncTask.access$300(AsyncTask.java:127)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.os.Handler.dispatchMessage(Handler.java:99)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.os.Looper.loop(Looper.java:123)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at android.app.ActivityThread.main(ActivityThread.java:4627)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at java.lang.reflect.Method.invokeNative(Native Method)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at java.lang.reflect.Method.invoke(Method.java:521)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  01-06 14:54:29.548: E/AndroidRuntime(18020):    at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>I get the same IllegalStateExeption when I implement the AsynTask as follows, because the findFragmentById() method returns a null pointer.</p>
  
  <pre><code>private class onFriendAddedAsyncTask extends AsyncTask&lt;String, Void, String&gt; {
  
      protected void onPreExecute() {
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute");
          FragmentManager fm = getSupportFragmentManager();
          FragmentTransaction ft = fm.beginTransaction();
          DummyFragment dummyFragment = DummyFragment.newInstance();
          ft.add(R.id.dummy_fragment_layout, dummyFragment);
          ft.commit();
      }
  
      protected void onPostExecute(String result) {
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute");
          FragmentManager fm = getSupportFragmentManager();
          FragmentTransaction ft = fm.beginTransaction();
          DummyFragment dummyFragment = (DummyFragment) fm.findFragmentById(R.id.dummy_fragment_layout);
          ft.remove(dummyFragment);
          ft.commitAllowingStateLoss();
      }
  </code></pre>
  
  <p>In the next step I use a handler for the adding and removing the DummyFragment. Additionally I've added some more debug output.</p>
  
  <pre><code>private class onFriendAddedAsyncTask extends AsyncTask&lt;String, Void, String&gt; {
  
      @Override
      protected void onPreExecute() {
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager());
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
  
          new Handler().post(new Runnable() {
              public void run() {
                  Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager());
                  Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
                  Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
                  FragmentManager fm = getSupportFragmentManager();
                  FragmentTransaction ft = fm.beginTransaction();
                  DummyFragment dummyFragment = DummyFragment.newInstance();
                  ft.add(R.id.dummy_fragment_layout, dummyFragment);
                  ft.commit();
              }
          });
  
      @Override
      protected void onPostExecute(String result) {
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager());
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
          Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
  
          new Handler().post(new Runnable() {
              public void run() {
                  Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager());
                  Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
                  Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
                  FragmentManager fm = getSupportFragmentManager();
                  FragmentTransaction ft = fm.beginTransaction();
                  DummyFragment dummyFragment = (DummyFragment) fm.findFragmentById(R.id.dummy_fragment_layout);
                  ft.remove(dummyFragment);
                  ft.commitAllowingStateLoss();
              }
          });
  </code></pre>
  
  <p>I get following LogCut:</p>
  
  <pre><code>01-07 19:00:17.273: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FragmentManager{45e384a8 in MyFragmentActivity{45e38358}}
  01-07 19:00:17.273: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute null
  01-07 19:00:17.273: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FriendListFragment{45e38ab0 #0 id=0x7f0a0002}
  01-07 19:00:17.283: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FragmentManager{45e384a8 in MyFragmentActivity{45e38358}}
  01-07 19:00:17.288: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/doInBackground
  01-07 19:00:17.288: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute null
  01-07 19:00:17.288: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FriendListFragment{45e38ab0 #0 id=0x7f0a0002}
  01-07 19:00:17.308: V/DummyFragment(4124): onAttach DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:17.308: V/DummyFragment(4124): onCreate DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:17.308: V/DummyFragment(4124): onCreateView DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:17.308: V/DummyFragment(4124): onActivityCreated DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:17.308: V/DummyFragment(4124): onStart DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:17.313: V/DummyFragment(4124): onResume DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.098: V/MyFragmentActivity(4124): onSaveInstanceState DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.098: V/DummyFragment(4124): onSaveInstanceState DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.098: V/MyFragmentActivity(4124): onPause DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.098: V/DummyFragment(4124): onPause DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.103: V/MyFragmentActivity(4124): onStop DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.103: V/DummyFragment(4124): onStop DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.103: V/MyFragmentActivity(4124): onDestroy DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.103: V/DummyFragment(4124): onDestroyView DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.108: V/DummyFragment(4124): onDestroy DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.113: V/DummyFragment(4124): onDetach DummyFragment{45dd7498 #2 id=0x7f0a0004}
  01-07 19:00:18.138: V/MyFragmentActivity(4124): onCreate
  01-07 19:00:18.138: V/FriendListFragment(4124): FriendListFragment
  01-07 19:00:18.138: V/FriendListFragment(4124): onAttach FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.138: V/FriendListFragment(4124): onCreate FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.148: V/DummyFragment(4124): onAttach DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.153: V/DummyFragment(4124): onCreate DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.523: V/MyFragmentActivity(4124): onStart DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.543: V/FriendListFragment(4124): onActivityCreated FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.548: V/DummyFragment(4124): onCreateView DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.548: V/DummyFragment(4124): onActivityCreated DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.548: V/FriendListFragment(4124): onLoadFinished FragmentManager{45d8e478 in MyFragmentActivity{45e4a6d8}}
  01-07 19:00:18.548: V/FriendListFragment(4124): onLoadFinished FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.553: V/DummyFragment(4124): onStart DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.553: V/FriendListFragment(4124): onLoadFinished FragmentManager{45d8e478 in MyFragmentActivity{45e4a6d8}}
  01-07 19:00:18.553: V/FriendListFragment(4124): onLoadFinished FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.558: V/MyFragmentActivity(4124): onResume DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.558: V/MyFragmentActivity(4124): onPostResume DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.558: V/MyFragmentActivity(4124): onResumeFragments DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.558: V/FriendListFragment(4124): onResume FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.563: V/FriendListFragment(4124): onCreateLoader FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.563: V/DummyFragment(4124): onResume DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
  01-07 19:00:18.723: V/FriendListFragment(4124): onLoadFinished FragmentManager{45d8e478 in MyFragmentActivity{45e4a6d8}}
  01-07 19:00:18.723: V/FriendListFragment(4124): onLoadFinished FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
  01-07 19:00:18.893: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute FragmentManager{45e384a8 in null}}
  01-07 19:00:18.893: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
  01-07 19:00:18.893: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
  01-07 19:00:18.923: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute FragmentManager{45e384a8 in null}}
  01-07 19:00:18.923: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
  01-07 19:00:18.923: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
  01-07 19:00:18.928: D/AndroidRuntime(4124): Shutting down VM
  01-07 19:00:18.928: W/dalvikvm(4124): threadid=1: thread exiting with uncaught exception (group=0x4001d7d0)
  01-07 19:00:18.938: E/AndroidRuntime(4124): FATAL EXCEPTION: main
  01-07 19:00:18.938: E/AndroidRuntime(4124): java.lang.IllegalStateException: Activity has been destroyed
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1329)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:548)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:536)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at com.xyz.dummy.MyFragmentActivity$onFriendAddedAsyncTask$2.run(MyFragmentActivity.java:476)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.os.Handler.handleCallback(Handler.java:587)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.os.Handler.dispatchMessage(Handler.java:92)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.os.Looper.loop(Looper.java:123)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at android.app.ActivityThread.main(ActivityThread.java:4627)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at java.lang.reflect.Method.invokeNative(Native Method)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at java.lang.reflect.Method.invoke(Method.java:521)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  01-07 19:00:18.938: E/AndroidRuntime(4124):     at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>In onPreExecute() the FriendListFragment has the id=0x7f0a0002. Inside the handler the DummyFragment is created with id=0x7f0a0004. In onPostExecute() both IDs are null.
  In onPreExecute() the address of MyFragmentActivity is 45e38358. but in onPostExecute() it's null. But in both methods the FragmentManager address is 45e384a8.
  I guess onPostExecute uses an invalid FragmentManager. But why?</p>