旋转设备后，NavController没有当前导航节点 [英] NavController no current navigation node after device rotation
问题描述
我正在制作支持不同设备方向的应用程序.导航由Android Jetpack的Navigation进行.下面是用于横向显示的应用主屏幕.它是列表包装器片段(它是NavHostFragment，它被添加到fragment标记中的活动布局)，包装器包括列表片段(fragment)和详细信息片段(FrameLayout).纵向方向类似(包装器和列表在其中，详细信息可通过抛出导航访问).
I am making app, which supports different device orientations. Navigation is carried out by Android Jetpack's Navigation. App main screen for landscape orientation is present below. It is list wrapper fragment (it is NavHostFragment, it is added to activity's layout in fragment tag), wrapper includes list fragment (fragment) and details fragment (FrameLayout). Portrait orientation is similar (wrapper and list in it, details is accessible throw navigation).
我的问题是我更改设备方向后出现异常
My problem is after I change device orientation I get exception
java.lang.IllegalStateException:当前没有导航节点
java.lang.IllegalStateException: no current navigation node
具有模拟数据的布局的第一个版本运行良好，在将ROOM添加到我的应用，新订单和更新订单片段后，出现错误.遗憾的是，我无法更准确地定位错误源.
First version of my layout with mocked data worked fine, the error appears after I add ROOM to my app, new order and update order fragments. It is a pity, I cannot localize source of error more exact.
列出包装器代码
class OrderListWrapperFragment : RxFragment() {
private val disposable = CompositeDisposable()
var selectedOrderId: Long = 0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val bundle = savedInstanceState ?: arguments
bundle?.let {
selectedOrderId = it.getLong(EXTRA_ORDER_ID)
}
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? = inflater.inflate(R.layout.orders__list_wrapper, container, false)
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
initializeToolbar(toolbar, getString(R.string.orders_title), false)
newOrderButton
.clicks()
.subscribe {
findNavController()
.navigate(R.id.action_orderListWrapperFragment_to_orderNewFragment)
}
.addTo(disposable)
childFragmentManager.registerFragmentLifecycleCallbacks(callback, false)
}
override fun onDestroyView() {
super.onDestroyView()
childFragmentManager.unregisterFragmentLifecycleCallbacks(callback)
disposable.clear()
}
override fun onSaveInstanceState(outState: Bundle) {
super.onSaveInstanceState(outState)
outState.putLong(EXTRA_ORDER_ID, selectedOrderId)
}
private val callback = object : FragmentManager.FragmentLifecycleCallbacks() {
private val disposable = CompositeDisposable()
override fun onFragmentResumed(fm: FragmentManager, fragment: Fragment) {
super.onFragmentResumed(fm, fragment)
if (fragment is OrderListFragment) {
fragment
.selectedItemIdChanges
.subscribeBy(onNext = {
selectedOrderId = it
if (orderDetailsContainer != null) {
childFragmentManager.commit {
replace(
R.id.orderDetailsContainer,
OrderDetailsFragment.newInstance(it)
)
}
} else {
findNavController()
.navigate(
R.id.action_orderListWrapperFragment_to_orderDetailsFragment,
bundleOf(EXTRA_ORDER_ID to it)
)
selectedOrderId = 0
}
},
onError = {
Log.d("detailView", it.toString())
})
.addTo(disposable)
val orderId = selectedOrderId
if (orderId != 0L) {
if (orderDetailsContainer != null) {
childFragmentManager.commit {
replace(
R.id.orderDetailsContainer,
OrderDetailsFragment.newInstance(orderId)
)
}
} else {
findNavController()
.navigate(//exception throws here
R.id.action_orderListWrapperFragment_to_orderDetailsFragment,
bundleOf(EXTRA_ORDER_ID to orderId)
)
selectedOrderId = 0
}
}
}
}
override fun onFragmentPaused(fm: FragmentManager, fragment: Fragment) {
super.onFragmentPaused(fm, fragment)
if (fragment is OrderListFragment) {
disposable.clear()
}
}
}
companion object {
private const val EXTRA_ORDER_ID = "EXTRA_ORDER_ID"
}
}
我的导航图
<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/navigation_graph"
app:startDestination="@id/orderListWrapperFragment">
<fragment
android:id="@+id/orderListWrapperFragment"
android:name="com.mtgshipping.app.orders.orderList.OrderListWrapperFragment"
android:label="OrderListWrapperFragment"
tools:layout="@layout/orders__list_wrapper">
<action
android:id="@+id/action_orderListWrapperFragment_to_orderDetailsFragment"
app:destination="@id/orderDetailsFragment"/>
<action
android:id="@+id/action_orderListWrapperFragment_to_orderNewFragment"
app:destination="@id/orderNewFragment"/>
<action
android:id="@+id/action_orderListWrapperFragment_to_orderUpdateFragment"
app:destination="@id/orderUpdateFragment"/>
</fragment>
<fragment
android:id="@+id/orderDetailsFragment"
android:name="com.mtgshipping.app.orders.orderDetails.OrderDetailsFragment"
android:label="OrderDetailsFragment"
tools:layout="@layout/orders__order_details">
<action
android:id="@+id/action_orderDetailsFragment_to_orderUpdateFragment"
app:destination="@id/orderUpdateFragment"/>
</fragment>
<fragment
android:id="@+id/orderNewFragment"
android:name="com.mtgshipping.app.orders.orderNew.OrderNewFragment"
android:label="OrderNewFragment"
tools:layout="@layout/orders__order_new">
<action
android:id="@+id/action_orderNewFragment_to_orderListWrapperFragment"
app:destination="@id/orderListWrapperFragment"/>
</fragment>
<fragment
android:id="@+id/orderUpdateFragment"
android:name="com.mtgshipping.app.orders.orderUpdate.OrderUpdateFragment"
android:label="OrderUpdateFragment"
tools:layout="@layout/orders__order_update">
<action
android:id="@+id/action_orderUpdateFragment_to_orderListWrapperFragment"
app:destination="@id/orderListWrapperFragment"/>
</fragment>
</navigation>
我在NavController中进行了一些调试，在设备旋转mGraph为null之后，它在第746 NavDestination currentNode = mBackStack.isEmpty() ? mGraph : mBackStack.getLast().getDestination();行中显示，其他私有字段也为null.可能是某些原因导致NavController无法正确初始化.如果需要的话，我可以提供布局和其他代码.
I made some debug in NavController, it showed in line 746 NavDestination currentNode = mBackStack.isEmpty() ? mGraph : mBackStack.getLast().getDestination(); after device rotation mGraph is null, other private fields is also null. Maybe something prevents NavController to initialize properly. I can provide layouts and other code, if it will be need.
推荐答案
感谢斯拉夫的评论，他是对的.我在应用程序模块build.gradle
Thanks to Slav's comment, he was right. I updated navigation module to 2.2.0 navigation_version = '2.2.0' in app's module build.gradle
implementation "androidx.navigation:navigation-fragment-ktx:$navigation_version"
implementation "androidx.navigation:navigation-ui-ktx:$navigation_version"
做完此问题后，不再出现，这似乎是导航中的错误.
After doing this problem is no longer appears, looks like that was a bug in navigation.
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