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

当我试图在onActivityForResult()方法中显示片段时,我总是得到这个,所以接下来的问题是:

我的活动暂停和停止,这意味着,onSaveInstanceState()已经被调用(对于pre-Honeycomb和post-Honeycomb设备)。 在任何结果的情况下,我使事务显示/隐藏片段,这导致这个IllegalStateException。

接下来我做的是:

增加了确定我想要的动作是否完成的值(例如,从camere - isPhotoTaken中拍摄照片)-它可以是布尔值或整数值,这取决于你需要多少不同的事务。 在重写onResumeFragments()方法中,我检查了我的值,并在我需要的片段事务之后。在这种情况下,commit()没有在onSaveInstanceState之后执行,因为状态是在onResumeFragments()方法中返回的。

其他回答

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)

My use case: I have used listener in fragment to notify activity that some thing happened. I did new fragment commit on callback method. This works perfectly fine on first time. But on orientation change the activity is recreated with saved instance state. In that case fragment is not created again implies that the fragment have the listener which is old destroyed activity. Any way the call back method will get triggered on action. It goes to destroyed activity which cause the issue. The solution is to reset the listener in fragment with current live activity. This solve the problem.

我在我的应用程序中有同样的问题。我已经解决了这个问题,只是调用super.onBackPressed();并在当前类上调用commitAllowingStateLoss()。

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();
    }
}

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