如果你试图在你的片段活动的onSaveInstanceState()被调用后执行片段转换，就会发生这样的异常。

发生这种情况的一个原因是，当一个活动停止时，如果你让一个AsyncTask(或线程)运行。

调用onSaveInstanceState()后的任何转换都可能丢失，如果系统回收活动的资源并稍后重新创建它。

读 http://chris-alexander.co.uk/on-engineering/dev/android-fragments-within-fragments/

篇文章。 fragment. isresume()检查帮助我在onDestroyView w/o使用onSaveInstanceState方法。

在Android源代码中查找导致此问题的原因，给出FragmentManagerImpl类(Activity中可用的实例)中的标记mStateSaved的值为true。当Activity#onSaveInstanceState调用后堆栈被保存(saveAllState)时，它被设置为true。 之后，来自ActivityThread的调用不会使用FragmentManagerImpl#noteStateNotSaved()和dispatch()中的可用重置方法重置该标志。

在我看来，有一些可用的修复，这取决于你的应用程序正在做什么和使用:

的好方法

首先，我要为Alex Lockwood的文章做广告。然后，根据我目前所做的:

For fragments and activities that don't need to keep any state information, call commitAllowStateLoss. Taken from documentation: Allows the commit to be executed after an activity's state is saved. This is dangerous because the commit can be lost if the activity needs to later be restored from its state, so this should only be used for cases where it is okay for the UI state to change unexpectedly on the user`. I guess this is alright to use if the fragment is showing read-only information. Or even if they do show editable info, use the callbacks methods to retain the edited info. Just after the transaction is commit (you just called commit()), make a call to FragmentManager.executePendingTransactions().

不推荐的方法:

As Ovidiu Latcu mentioned above, don't call super.onSaveInstanceState(). But this means you will lose the whole state of your activity along with fragments state. Override onBackPressed and in there call only finish(). This should be OK if you application doesn't use Fragments API; as in super.onBackPressed there is a call to FragmentManager#popBackStackImmediate(). If you are using both Fragments API and the state of your activity is important/vital, then you could try to call using reflection API FragmentManagerImpl#noteStateNotSaved(). But this is a hack, or one could say it's a workaround. I don't like it, but in my case it's quite acceptable since I have a code from a legacy app that uses deprecated code (TabActivity and implicitly LocalActivityManager).

下面是使用反射的代码:

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    invokeFragmentManagerNoteStateNotSaved();
}

@SuppressWarnings({ "rawtypes", "unchecked" })
private void invokeFragmentManagerNoteStateNotSaved() {
    /**
     * For post-Honeycomb devices
     */
    if (Build.VERSION.SDK_INT < 11) {
        return;
    }
    try {
        Class cls = getClass();
        do {
            cls = cls.getSuperclass();
        } while (!"Activity".equals(cls.getSimpleName()));
        Field fragmentMgrField = cls.getDeclaredField("mFragments");
        fragmentMgrField.setAccessible(true);

        Object fragmentMgr = fragmentMgrField.get(this);
        cls = fragmentMgr.getClass();

        Method noteStateNotSavedMethod = cls.getDeclaredMethod("noteStateNotSaved", new Class[] {});
        noteStateNotSavedMethod.invoke(fragmentMgr, new Object[] {});
        Log.d("DLOutState", "Successful call for noteStateNotSaved!!!");
    } catch (Exception ex) {
        Log.e("DLOutState", "Exception on worka FM.noteStateNotSaved", ex);
    }
}

干杯!

My use case: I have used listener in fragment to notify activity that some thing happened. I did new fragment commit on callback method. This works perfectly fine on first time. But on orientation change the activity is recreated with saved instance state. In that case fragment is not created again implies that the fragment have the listener which is old destroyed activity. Any way the call back method will get triggered on action. It goes to destroyed activity which cause the issue. The solution is to reset the listener in fragment with current live activity. This solve the problem.

这是我迄今为止遇到的最愚蠢的错误。我有一个片段应用程序工作完美的API < 11，并强制关闭API > 11。

我真的不知道他们在saveInstance调用的活动生命周期内改变了什么，但我在这里是我如何解决这个问题的:

@Override
protected void onSaveInstanceState(Bundle outState) {
    //No call for super(). Bug on API Level > 11.
}

我只是不调用.super()，一切都很好。我希望这将为您节省一些时间。

编辑:经过进一步研究，这是支持包中的一个已知错误。

如果你需要保存实例，并添加一些东西到你的outState Bundle，你可以使用以下方法:

@Override
protected void onSaveInstanceState(Bundle outState) {
    outState.putString("WORKAROUND_FOR_BUG_19917_KEY", "WORKAROUND_FOR_BUG_19917_VALUE");
    super.onSaveInstanceState(outState);
}

EDIT2:如果您试图在Activity在后台消失后执行事务，也可能会发生这种情况。为了避免这种情况，你应该使用commitAllowingStateLoss()

EDIT3: The above solutions were fixing issues in the early support.v4 libraries from what I can remember. But if you still have issues with this you MUST also read @AlexLockwood 's blog : Fragment Transactions & Activity State Loss Summary from the blog post (but I strongly recommend you to read it) : NEVER commit() transactions after onPause() on pre-Honeycomb, and onStop() on post-Honeycomb Be careful when committing transactions inside Activity lifecycle methods. Use onCreate(), onResumeFragments() and onPostResume() Avoid performing transactions inside asynchronous callback methods Use commitAllowingStateLoss() only as a last resort

这发生在你试图加载一个片段，但活动已改变其状态为onPause()。例如，当您试图获取数据并将其加载到活动中，但当用户单击某个按钮并移动到下一个活动时，就会发生这种情况。

你可以用两种方法解决这个问题

您可以使用transaction.commitAllowingStateLoss()而不是transaction.commit()来加载片段，但您可能最终会丢失已完成的提交操作。

or

在加载片段时，确保活动处于恢复状态，而不是进入暂停状态。 创建一个布尔值并检查activity是否不进入onPause()状态。

@Override
public void onResume() {
    super.onResume();
    mIsResumed = true;
}

@Override
public void onPause() {
    mIsResumed = false;
    super.onPause();
}

然后，而加载片段检查活动是否存在，只有当活动是前景时才加载。

if(mIsResumed){
 //load the fragment
}