java.lang.IllegalStateException：onSaveInstanceState后无法执行此操作

Question

我正在为我的应用程序使用支持库。在我的FragmentActivity中，我使用AsyncTask从互联网下载数据。在onPreExecute（）方法中，我添加一个片段，并在onPostExecute（）方法中再次移除它。当方向改变时，我得到了上述例外。请看看细节：

private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> { 
    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"); 
    ... 
} 

我获得以下LogCut：

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) 

在有关的原因似乎是，该onPostExecute方法的的onResume之前调用类似问题的其他线程（）方法叫做。但即使onResume（）之前被调用，我也会得到异常。

有人知道有什么问题吗？

的活动是这样的：

public class MyFragmentActivity extends FragmentActivity implements OnFriendSelectedListener, OnFriendAddedListener, OnFriendOptionSelectedListener, LoaderCallbacks<Cursor> { 

@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() > 0) { 
     new onFriendAddedAsyncTask().execute(name); 
    } 
} 

使用commitAllowingStateLoss（）我得到以下异常：

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) 

我得到的，当我实现AsynTask如下相同IllegalStateExeption，因为findFragmentById（）方法返回一个空指针。

private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> { 

    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(); 
    } 

在下一步中，我使用处理程序添加和删除DummyFragment。另外我添加了一些更多的调试输出。

private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> { 

    @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(); 
      } 
     }); 

我获得以下LogCut：

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) 

在onPreExecute（）的FriendListFragment具有ID = 0x7f0a0002。在处理程序中，创建DummyFragment，id = 0x7f0a0004。在onPostExecute（）中，这两个ID都是空的。 在onPreExecute（）中MyFragmentActivity的地址是45e38358。但在onPostExecute（）它是空的。但是在这两种方法中，FragmentManager地址都是45e384a8。 我想onPostExecute使用无效的FragmentManager。但为什么？

Answer 1

你应该做的Handler事务，如下所示：

@Override 
protected void onPostExecute(String result) { 
    Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute"); 
    new Handler().post(new Runnable() { 
      public void run() { 
       fm = getSupportFragmentManager(); 
       ft = fm.beginTransaction(); 
       ft.remove(dummyFragment); 
       ft.commit(); 
      } 
     }); 
} 

Answer 2

的原因的例外是AsyncTask的运行时间和访问到以前期间FragmentActivity的再创造，破坏FragmentActivity之后在onPostExecute()。

问题是要获得新的FragmentActivity的有效参考。对于这个既不是getActivity()也不是findById()或类似的东西。本论坛充满了根据这个问题的线索（例如搜索"Activity context in onPostExecute"）。其中一些正在描述解决方法（直到现在我没有找到一个好的）。

也许这将是一个更好的解决方案，使用服务为我的目的。

Answer 3

谢谢Oleg Vaskevich。使用FragmentActivity的WeakReference解决了这个问题。我的代码看起来如下：

public class MyFragmentActivity extends FragmentActivity implements OnFriendAddedListener { 

    private static WeakReference<MyFragmentActivity> wrActivity = null; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     wrActivity = new WeakReference<MyFragmentActivity>(this); 
     ... 

    private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> { 

     @Override 
     protected void onPreExecute() { 
      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) { 
      final Activity activity = wrActivity.get(); 
      if (activity != null && !activity.isFinishing()) { 
       FragmentManager fm = activity.getSupportFragmentManager(); 
       FragmentTransaction ft = fm.beginTransaction(); 
       DummyFragment dummyFragment = (DummyFragment) fm.findFragmentById(R.id.dummy_fragment_layout); 
       ft.remove(dummyFragment); 
       ft.commitAllowingStateLoss(); 
      } 
     } 

Answer 4

它的价值;我在后台运行服务的应用程序出现此错误。在他们中的一个上，必须向用户显示超时对话框。该对话框是导致此错误的问题，如果应用程序不再在前台运行。

在我们的例子中，当应用程序处于后台时，对话框没有用，所以我们只保留跟踪（布尔标记onPause en onResume），然后仅在用户可见时才显示对话框。

Answer 5

我相信这个问题的正确答案是以下方法。

public abstract int commitAllowingStateLoss() 

赞提交（），但允许提交要执行的活动的 状态保存后。这很危险，因为如果 该活动需要稍后从其状态恢复，则该提交可能会丢失，所以这个应该只用于UI状态在用户意外改变 的情况。

以上描述涉及这种方法。

protected void onSaveInstanceState(android.os.Bundle outState) 

这个问题正是当设备进入睡眠状态时。

http://developer.android.com/reference/android/app/FragmentTransaction.html

Answer 6

这事对我来说，因为我是从调用小碎片commit()这是泄漏的活动。它保持活动作为一个属性和旋转活动变量没有更新onAttach();所以我试图通过保留(setRetainInstance(true);)片段来提交僵尸活动上的交易。

Answer 7

我有一个类似的问题，我通过将onResume()中的一些片段事务代码移动到onStart()来解决。

更确切地说：我的应用程序是一个启动器。按下Android主页按钮后，用户可以选择一个启动器，直到他/她的决定被记住。当此时“回退”（例如通过轻敲灰色区域），应用程序崩溃。

也许这有助于某人。

Answer 8

短而有效的解决方案：

按照简单的步骤：

步骤1：覆盖在各分段onSaveInstanceState状态。并从中删除超级方法。

@Override 
public void onSaveInstanceState(Bundle outState) { 
} 

步骤2：使用CommitAllowingStateLoss();代替commit();而片段操作。

fragmentTransaction.commitAllowingStateLoss(); 

Answer 9

检查显示片段前是否有活动isFinishing()。

例子：

if(!isFinishing()) { 
FragmentManager fm = getSupportFragmentManager(); 
      FragmentTransaction ft = fm.beginTransaction(); 
      DummyFragment dummyFragment = DummyFragment.newInstance(); 
      ft.add(R.id.dummy_fragment_layout, dummyFragment); 
      ft.commitAllowingStateLoss(); 
} 

Answer 10

我的应用程序有3秒的片段来装载，但是当拳头屏幕正准备表演，我按Home键，恢复运行它，它表现出了同样的错误，所以编辑我的代码，它跑得非常顺利：

new Handler().post(new Runnable() { 
     public void run() { 
      if (saveIns == null) { 
       mFragment = new Fragment_S1_loading(); 
       getFragmentManager().beginTransaction() 
         .replace(R.id.container, mFragment).commit(); 
      } 
      getActionBar().hide(); 
      // Loading screen in 3 secs: 
      mCountDownTimerLoading = new CountDownTimer(3000, 1000) { 

       @Override 
       public void onTick(long millisUntilFinished) { 

       } 

       @Override 
       public void onFinish() { 
        if (saveIns == null) {// TODO bug when start app and press home 
              // button 
         getFragmentManager() 
           .beginTransaction() 
           .replace(R.id.container, 
             new Fragment_S2_sesstion1()).commitAllowingStateLoss(); 
        } 
        getActionBar().show(); 
       } 
      }.start(); 
     } 
    }); 

注：添加commitAllowingStateLoss（），而不是提交（）

Answer 11

解决方案1： 覆盖onSaveInstanceState()并删除其中的超级调用。

@Override 
public void onSaveInstanceState(Bundle outState) { 
} 

解决方案2： 覆盖onSaveInstanceState()和超级呼叫

@Override 
public void onSaveInstanceState(Bundle outState) { 
    // TODO: Add code to remove fragment here 
    super.onSaveInstanceState(outState); 
} 

Answer 12

从支持库版本24.0.0开始之前删除您的片段，你可以调用FragmentTransaction.commitNow()方法，提交本次交易同步，而不是打电话commit()其次executePendingTransactions()

Answer 13

这个问题发生在一个进程ess试图操纵已调用onStop()的活动。它不一定与片段事务绑定，但也可以使用onBackPressed（）等其他方法。

除了AsyncTask之外，这种问题的另一个来源是总线模式订阅的错位。通常事件总线或RxBus的订阅在Activity的onCreate中注册并在onDestroy中注销。如果一个新的Activity启动并发布一个事件被前一个Activity的拦截，那么它可能会产生这个错误。如果发生这种情况，则一种解决方案是将订阅注册和注销注册到onStart()和onStop()。

Answer 14

对于这个问题，有一种替代解决方案（不是最好的解决方案），但有效。使用标志，你可以处理它，就像下面

/** 
* Flag to avoid "java.lang.IllegalStateException: Can not perform this action after 
* onSaveInstanceState". Avoid Fragment transaction until onRestoreInstanceState or onResume 
* gets called. 
*/ 
private boolean isOnSaveInstanceStateCalled = false; 


@Override 
public void onRestoreInstanceState(final Bundle bundle) { 
    ..... 
    isOnSaveInstanceStateCalled = false; 
    ..... 
} 

@Override 
public void onSaveInstanceState(final Bundle outState) { 
    ..... 
    isOnSaveInstanceStateCalled = true; 
    ..... 
} 

@Override 
public void onResume() { 
    super.onResume(); 
    isOnSaveInstanceStateCalled = false; 
    ..... 
} 

而且，在做片段的交易，你可以检查此boolean值。

private void fragmentReplace(Fragment fragment, String fragmentTag){ 
    if (!isOnSaveInstanceStateCalled) { 
     getSupportFragmentManager() 
       .beginTransaction() 
       .replace(R.id.layout_container, fragment, fragmentTag) 
       .commit(); 
    } 
}