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

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!

其他回答

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();
}

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!

解决这个问题的另一种生命周期方法是使用kotlin最新发布的lifecycle-ktx。

lifecycleScope.launchWhenResumed {
    // your code with fragment or dialogfragment
}

闭包将在恢复状态后运行,因此甚至在恢复状态后调用此方法 停,等下一份简历来的时候就安全执行了。

你也可以选择喜欢

lifecycleScope.launchWhenCreated
// or
lifecycleScope.launchWhenStarted

适合你的情况。

当销毁完成时,代码将被取消。

谷歌文档链接: https://developer.android.com/kotlin/ktx#lifecycle

我有同样的问题,得到IllegalStateException,但替换所有调用commit()与commitAllowingStateLoss()没有帮助。

罪魁祸首是调用DialogFragment.show()。

我用

try {
    dialog.show(transaction, "blah blah");
}
catch(IllegalStateException e) {
    return;
}

这样就成功了。好吧,我没有展示对话,但在这种情况下,这是可以的。

这是我的应用程序中唯一一个我第一次调用FragmentManager.beginTransaction()但从未调用commit()的地方,所以当我寻找“commit()”时,我没有找到它。

有趣的是,用户从未离开该应用。相反,出现的AdMob插页广告才是罪魁祸首。

这对我很管用……我自己发现的…希望对你有所帮助!

1)不要有全局的“静态”FragmentManager / FragmentTransaction。

2) onCreate,总是初始化FragmentManager再次!

样本如下:-

public abstract class FragmentController extends AnotherActivity{
protected FragmentManager fragmentManager;
protected FragmentTransaction fragmentTransaction;
protected Bundle mSavedInstanceState;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mSavedInstanceState = savedInstanceState;
    setDefaultFragments();
}

protected void setDefaultFragments() {
    fragmentManager = getSupportFragmentManager();
    //check if on orientation change.. do not re-add fragments!
    if(mSavedInstanceState == null) {
        //instantiate the fragment manager

        fragmentTransaction = fragmentManager.beginTransaction();

        //the navigation fragments
        NavigationFragment navFrag = new NavigationFragment();
        ToolbarFragment toolFrag = new ToolbarFragment();

        fragmentTransaction.add(R.id.NavLayout, navFrag, "NavFrag");
        fragmentTransaction.add(R.id.ToolbarLayout, toolFrag, "ToolFrag");
        fragmentTransaction.commitAllowingStateLoss();

        //add own fragment to the nav (abstract method)
        setOwnFragment();
    }
}