当用户旋转屏幕以便加载与新方向相关的资源时，onSaveInstance将被调用。

有可能这个用户旋转了屏幕，然后按了后退按钮(因为也有可能这个用户在使用你的应用程序时摸不着他们的手机)

Android 4.2和支持库的源代码中修正了这个问题。[*]

有关原因(和解决方案)的详细信息，请参阅谷歌错误报告: http://code.google.com/p/android/issues/detail?id=19917

如果你正在使用支持库，那么你不应该担心这个错误(很长时间)[*]。然而，如果你直接使用API(即不使用支持库的FragmentManager)，并针对Android 4.2以下的API，那么你将需要尝试一种变通方法。

[*]在撰写本文时，Android SDK管理器仍在分发显示此错误的旧版本。

编辑，我要在这里补充一些澄清，因为我显然把投票反对这个答案的人弄糊涂了。

There are several different (but related) circumstances that can cause this exception to be thrown. My answer above is referring to the specific instance discussed in the question i.e. a bug in Android which has subsequently been fixed. If you're getting this exception for another reason it's because you're adding/removing fragments when you shouldn't be (after fragment states have been saved). If you're in such a situation then perhaps "Nested Fragments - IllegalStateException “Can not perform this action after onSaveInstanceState”" can be of use to you.

你可能会调用fragmentManager.popBackStackImmediate();当活动暂停时。活动未完成，但处于暂停状态，且不在前台。你需要在popBackStackImmediate()之前检查activity是否被暂停。

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!

我也有同样的问题，经过一天的分析，所有的文章，博客和stackoverflow，我找到了一个简单的解决方案。完全不要使用savedInstanceState，这是一行代码的条件。在片段代码上:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(null);
    .....

谢谢@gunar，但我认为有更好的方法。

医生说:

*如果您提交的单个事务没有修改 *碎片回栈，强烈考虑使用 * {@link FragmentTransaction#commitNow()}代替。这有助于避免 *当应用程序中的其他代码未提交时，会产生不必要的副作用 *需要不同时间的事务。 ＊ * @return如果有任何待处理事务则返回true *执行。 * / executePendingTransactions();

所以使用commitNow替换:

fragmentTransaction.commit();
FragmentManager.executePendingTransactions()