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)

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!

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
}

在我的例子中，有相同的错误异常，我把“onBackPressed()”放在一个可运行对象中(你可以使用你的任何视图):

myView.post(new Runnable() {
                    @Override
                    public void run() {
                        onBackPressed()
                    }
                });

我不知道为什么，但它有效!

在屏幕被锁定\blank并且Activity +对话框的实例状态被保存之后，在对话框片段上调用dismiss()也会发生这种情况。要绕过这个调用:

dismissAllowingStateLoss()

实际上，每次我解散一个对话框时，我都不再关心它的状态了，所以这样做是可以的——实际上你并没有失去任何状态。

只需在显示你的片段之前调用super.onPostResume()，或者在调用super.onPostResume()之后在onPostResume()方法中移动你的代码。这就解决了问题!