IssueTracker

I have two Activities, MainActivity and SecondActivity. Using Navigation architecture in MainActivity, which has two fragments, such as HomeFragment and DetailFragment, the Navigation diagram is declared as follows:

<?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"
    android:id="@+id/navigation_home_flow"
    app:startDestination="@id/home_root_fragment">

    <fragment
        android:id="@id/home_root_fragment"
        android:name=".home.HomeFragment"
        android:label="HomeFragment">

    </fragment>

    <fragment
        android:id="@id/detail_fragment"
        android:name=".home.DetailFragment"
        android:label="DetailFragment">
    </fragment>
    
</navigation>

Generate ViewModels in the DetailFragment onCreate with "by navGraphViewModels".

class BaseImmerseFragment : BaseFragment() {

    companion object {
        const val TAG = "DetailFragment"
    }

    val vm by navGraphViewModels<ViewModel>(R.id.navigation_home_flow)


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        //init vm
        LogUtils.d(TAG, "init $vm")
    }
}

There is a button in DetailFragment, clicking it will jump to SecondActivity, when "Do not keep background Activity" is enabled, pressing the back button in SecondActivity will trigger the program crash：

Process: xxxxx, PID: 24236
java.lang.RuntimeException: Unable to start activity ComponentInfo{xxxxxx/xxxx.MainActivity}: java.lang.IllegalStateException: You cannot access the NavBackStackEntry's ViewModels until it is added to the NavController's back stack (i.e., the Lifecycle of the NavBackStackEntry reaches the CREATED state).
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3739)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3892)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2267)
    at com.didichuxing.doraemonkit.kit.timecounter.instrumentation.ProxyHandlerCallback.handleMessage(ProxyHandlerCallback.java:44)
    at android.os.Handler.dispatchMessage(Handler.java:103)
    at android.os.Looper.loop(Looper.java:217)
    at android.app.ActivityThread.main(ActivityThread.java:7993)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:502)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:955)
 Caused by: java.lang.IllegalStateException: You cannot access the NavBackStackEntry's ViewModels until it is added to the NavController's back stack (i.e., the Lifecycle of the NavBackStackEntry reaches the CREATED state).
    at androidx.navigation.NavBackStackEntry.getViewModelStore(NavBackStackEntry.kt:174)
    at xxxxx.DetailFragment$special$$inlined$navGraphViewModels$default$2.invoke(NavGraphViewModelLazy.kt:59)
    at xxxxx.DetailFragment$special$$inlined$navGraphViewModels$default$2.invoke(NavGraphViewModelLazy.kt:58)
    at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:53)
    at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:41)
    at xxxxx.DetailFragment.getVm(DetailFragment.kt:50)
    at xxxxx.DetailFragment.onCreate(DetailFragment.kt:102)
    at androidx.fragment.app.Fragment.performCreate(Fragment.java:2947)
    at androidx.fragment.app.FragmentStateManager.create(FragmentStateManager.java:455)
    at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:255)
    at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:113)
    at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1331)
    at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:2772)

If I put the vm creation declaration in the onViewCreated lifecycle or later, there will be no crashes.

Does "by navGraphViewModels" necessarily require the user to use it this way?

In my opinion, as long as the NavBackStackEntry viewModelStore corresponding to "R.id.navigation_home_flow" is in the CREATED state, it's OK, not the DetailFragment.

The Navigation version I use is 2.4.0-alpha06.

Thanks in advance if you can address my issue.