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)  

当前回答

当我在一个片段中使用startactivity时,我会得到这个异常;

当我改变使用startactivityforresult时,异常消失了:)

所以修复它的简单方法是使用startActivityForResult api:)

其他回答

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!

我对这个问题的解决方案是

在片段中添加方法:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    ...
    guideMapFragment = (SupportMapFragment)a.getSupportFragmentManager().findFragmentById(R.id.guideMap);
    guideMap = guideMapFragment.getMap();
    ...
}

@Override
public void onDestroyView() {
    SherlockFragmentActivity a = getSherlockActivity();
    if (a != null && guideMapFragment != null) {
        try {
            Log.i(LOGTAG, "Removing map fragment");
            a.getSupportFragmentManager().beginTransaction().remove(guideMapFragment).commit();
            guideMapFragment = null;
        } catch(IllegalStateException e) {
            Log.i(LOGTAG, "IllegalStateException on exit");
        }
    }
    super.onDestroyView();
}

可能很糟糕,但找不到更好的了。

好吧,在尝试了以上所有的解决方案都没有成功(因为基本上我没有事务)。

在我的情况下,我使用alertdialog和ProgressDialog作为片段,有时,在旋转时,当请求FragmentManager时,错误会上升。

我找到了一个混合了许多类似帖子的变通方法:

这是一个3步解决方案,所有在你的FragmentActivity(在这种情况下,它被称为GenericActivity):

private static WeakReference<GenericActivity> activity = null; //To avoid bug for fragments: Step 1 of 3

@Override
protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    //To avoid bug for fragments: Step 2 of 3
    activity = new WeakReference<GenericActivity>(this);
}

@Override
public FragmentManager getSupportFragmentManager(){
    //To avoid bug for fragments: Step 3 of 3
    if (this == activity.get()) {
        return super.getSupportFragmentManager();
    }
    return activity.get().getSupportFragmentManager();
}

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。

我发现,如果另一个应用程序是对话类型,并允许触摸被发送到后台应用程序,那么几乎任何后台应用程序都会崩溃与此错误。 我认为我们需要在每次执行事务时检查实例是否保存或恢复。