我有一个Live Android应用程序,从市场上我收到了以下堆栈跟踪,我不知道为什么它会发生,因为它不是发生在应用程序代码中,而是由应用程序的一些或其他事件引起的(假设)
我没有使用片段,仍然有一个FragmentManager的参考。
如果有人能揭示一些隐藏的事实,以避免这类问题:
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1109)
at android.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager.java:399)
at android.app.Activity.onBackPressed(Activity.java:2066)
at android.app.Activity.onKeyDown(Activity.java:1962)
at android.view.KeyEvent.dispatch(KeyEvent.java:2482)
at android.app.Activity.dispatchKeyEvent(Activity.java:2274)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1668)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1720)
at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1258)
at android.app.Activity.dispatchKeyEvent(Activity.java:2269)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1668)
at android.view.ViewRoot.deliverKeyEventPostIme(ViewRoot.java:2851)
at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2824)
at android.view.ViewRoot.handleMessage(ViewRoot.java:2011)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4025)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)
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
我有这个问题。但是我认为这个问题与commit和commitAllowStateLoss无关。
下面的堆栈跟踪和异常消息是关于commit()的。
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1341)
at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1352)
at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:574)
但是这个异常是由onBackPressed()引起的
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.support.v4.app.FragmentManagerImpl.checkStateLoss(Unknown Source)
at android.support.v4.app.FragmentManagerImpl.popBackStackImmediate(Unknown Source)
at android.support.v4.app.FragmentActivity.onBackPressed(Unknown Source)
它们都是由checkStateLoss()引起的
private void checkStateLoss() {
if (mStateSaved) {
throw new IllegalStateException(
"Can not perform this action after onSaveInstanceState");
}
if (mNoTransactionsBecause != null) {
throw new IllegalStateException(
"Can not perform this action inside of " + mNoTransactionsBecause);
}
mStateSaved在onSaveInstanceState之后为真。
这个问题很少发生。我从来没有遇到过这个问题。我不能再出现这个问题。
我找到了25517号
它可能在下列情况下发生
Back键在onSaveInstanceState之后,但在新活动开始之前被调用。
在代码中使用onStop()
我不确定问题的根源是什么。
所以我用了一个丑陋的方法。
@Override
public void onBackPressed() {
try{
super.onBackPressed();
}catch (IllegalStateException e){
// can output some information here
finish();
}
}
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.