Backstack 管理:Restarter 必须仅在所有者的初始化阶段创建 [英] Backstack management : Restarter must be created only during owner's initialization stage

问题描述

我在 MainActivity 中使用底部导航栏来处理一些片段.这是用于在它们之间切换的代码:

I am using a bottom navigation bar in my MainActivity to handle some fragments. This is the code used for switching between them:

private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
    if (item.isChecked &&
        supportFragmentManager.findFragmentById(R.id.act_main_fragment_container) != null
    )
        return@OnNavigationItemSelectedListener false
    val fragment =
        when (item.itemId) {
            R.id.navigation_home      -> fragments[0]
            R.id.navigation_bookings  -> fragments[1]
            R.id.navigation_messages  -> fragments[2]
            R.id.navigation_dashboard -> fragments[3]
            R.id.navigation_profile   -> fragments[4]
            else                      -> fragments[0]
        }
    this replaceWithNoBackStack fragment
    return@OnNavigationItemSelectedListener true
}

replaceWithNoBackstack 方法只是一个简写:

the method replaceWithNoBackstack is just a short-hand for this:

supportFragmentManager
    ?.beginTransaction()
    ?.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
    ?.replace(containerId, fragment)
    ?.commit()

问题是，当我在它们之间更快地切换时，我的应用程序崩溃并出现以下异常:

The problem is that when i switch faster between them, my app crashes with the following exception:

java.lang.IllegalStateException: Restarter 必须仅在所有者初始化阶段创建在 androidx.savedstate.SavedStateRegistryController.performRestore(SavedStateRegistryController.java:59)在 androidx.fragment.app.Fragment.performCreate(Fragment.java:2580)在 androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:837)在 androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1237)在 androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1302)在 androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)在 androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2075)在 androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1865)在 androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1820)在 androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1726)在 androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java:150)在 android.os.Handler.handleCallback(Handler.java:789)在 android.os.Handler.dispatchMessage(Handler.java:98)在 android.os.Looper.loop(Looper.java:164)在 android.app.ActivityThread.main(ActivityThread.java:6709)在 java.lang.reflect.Method.invoke(Native Method)在 com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)我一直在寻找，但找不到答案.

java.lang.IllegalStateException: Restarter must be created only during owner's initialization stage at androidx.savedstate.SavedStateRegistryController.performRestore(SavedStateRegistryController.java:59) at androidx.fragment.app.Fragment.performCreate(Fragment.java:2580) at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:837) at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1237) at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1302) at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439) at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2075) at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1865) at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1820) at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1726) at androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java:150) at android.os.Handler.handleCallback(Handler.java:789) at android.os.Handler.dispatchMessage(Handler.java:98) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:6709) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769) I've been searching a lot and couldn't find an answer.

如果我执行 API 调用，将应用程序置于后台，等待响应，当我返回应用程序时，应用程序崩溃，因为我试图立即显示对话框片段，我也会收到此错误(我认为发生这种情况的原因是从后台返回时重新创建片段的事务在显示对话框片段时仍在进行中).我通过为对话框设置 500 毫秒的延迟以一种hacky 的方式解决了这个问题，因为我想不出其他解决方案.

I also got this error if I do an API call, put the app in background, wait for the response, and at the time I go back to the app, the app crashes because I am trying to display a dialog fragment immediately (the reason I think this is happening is that the transaction of recreating the fragment when coming back from the background is still in progress at the time of displaying the dialog fragment). I solved this in a hacky way by setting a 500ms delay for the dialog because I couldn't figure out other solutions.

请询问您是否需要有关此的更多详细信息.提前谢谢你！

Please ask if you need more details regarding this. Thank you in advance!

可能的临时解决方案

编辑我通过将应用程序兼容性依赖降级到 androidx.appcompat:appcompat:1.0.2 解决了这个问题，但这只是一个临时解决方案，因为我将来必须更新它.我希望有人能弄清楚.

EDIT I solved this issue by downgrading the app compat depedency to androidx.appcompat:appcompat:1.0.2 but this is just a temporary solution, since i will have to update it in future. I'm hoping someone will figure it out.

编辑 2我通过从片段事务中删除 setTransition() 解决了这个问题.至少我知道安卓应用一般没有很好的过渡的原因

EDIT 2 I solved the issue by removing setTransition() from fragment transactions. At least I know the reason why android apps does not have good transitions in general

编辑 3也许避免这个问题并使事情顺利进行的最佳解决方案就是使用 ViewPager 来处理底部栏导航

EDIT 3 Maybe the best solution to avoid this issue and also make things work smoothly is just to use ViewPager to handle bottom bar navigation

推荐答案

如果您使用的是androidx.core:core-ktx:1.0.2"，尝试更改为 1.0.1

如果您正在使用生命周期(或 rxFragment)和 androidx_appcompat:alpha05，请尝试更改版本.
例如) appcompat : 1.1.0-beta01 或 1.0.2

If you're using lifecycle(or rxFragment) and androidx_appcompat:alpha05, try changeing versio.
ex) appcompat : 1.1.0-beta01 or 1.0.2

我认为在重用目标片段时保存状态时会出现错误(onPause-onResume).

I think's that it appears as an error when saving the state when the target fragment is reused (onPause-onResume).

这篇关于Backstack 管理:Restarter 必须仅在所有者的初始化阶段创建的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！