Error while navigating back in nested navigation

[Trassive]

FATAL EXCEPTION: main
Process: com.example.bookbuddy
java.lang.IllegalStateException: Fragment no longer exists for key f2: unique id 447abe67-0d63-454e-91d1-87f37f3e0c95
at androidx.fragment.app.FragmentManager.getFragment(FragmentManager.java:1271)
at org.readium.r2.navigator.pager.R2FragmentPagerAdapter.restoreState(R2FragmentPagerAdapter.kt:170)
at org.readium.r2.navigator.pager.R2PagerAdapter.restoreState(R2PagerAdapter.kt:114)
at org.readium.r2.navigator.pager.DelegatingPagerAdapter.restoreState(DelegatingPagerAdapter.java:114)
at androidx.viewpager.widget.ViewPager.onRestoreInstanceState(ViewPager.java:1461)
at org.readium.r2.navigator.pager.R2RTLViewPager.onRestoreInstanceState(R2RTLViewPager.java:185)
at android.view.View.dispatchRestoreInstanceState(View.java:22254)
at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:4028)
at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:4034)
at android.view.View.restoreHierarchyState(View.java:22232)
at androidx.fragment.app.Fragment.restoreViewState(Fragment.java:703)
at androidx.fragment.app.Fragment.restoreViewState(Fragment.java:3181)
at androidx.fragment.app.Fragment.performActivityCreated(Fragment.java:3166)
at androidx.fragment.app.FragmentStateManager.activityCreated(FragmentStateManager.java:639)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:289)
at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2164)
at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2059)
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:702)
at android.os.Handler.handleCallback(Handler.java:958)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:205)
at android.os.Looper.loop(Looper.java:294)
at android.app.ActivityThread.main(ActivityThread.java:8177)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

@composable
fun ReaderContent(fragment: EpubNavigatorFragment, onViewInflated: ()->Unit, containerId: Int){
var isViewInflated by remember { mutableStateOf(false) }
val fragmentManager = (LocalContext.current as FragmentActivity).supportFragmentManager

DisposableEffect(fragment) {
    onDispose {
        val existingFragment = fragmentManager.findFragmentById(containerId)
        if(existingFragment != null ){
            fragmentManager.beginTransaction().remove(fragment).commitNowAllowingStateLoss()
        }
    }
}
AndroidView(
    factory = {context->
        FragmentContainerView(context).apply {
            id = containerId

            fragmentManager.beginTransaction()
                .replace(id,fragment)
                .commit()
        }
    },
    update = {
        if(!isViewInflated){
            onViewInflated()
            isViewInflated = true
        }
    }
)

}
containterID is constant the fragment is created by the viewmodel so that it can perform business logic easily and on any change like the different book it creates a new fragment

[mickael-menu]

Try with an AndroidFragment composable instead: #552 (comment)

[Trassive]

I attempted to use AndroidFragment, but encountered an issue because it doesn't have an empty constructor. This fragment relies on constructor parameters for its dependencies, while the AndroidFragment composable uses a bundle for passing arguments for a fragment which have an empty constructor.

To work around this, I tried creating an intermediate fragment, but I ran into various errors during the process

[mickael-menu]

The EpubNavigatorFragment requires a fragment factory, see https://github.com/readium/kotlin-toolkit/blob/develop/docs/guides/navigator/navigator.md#epubnavigatorfragment

Even if you use AndroidFragment, you need to set the fragment factory in the hosting Activity.

Note that Jetpack Compose is not officially supported by Readium yet, so you might still encounter other issues. I'm not sure it was ever used in production with Jetpack Compose.

[Trassive]

Thanks for the help! I managed to stop the crashes yesterday somehow, but I still encountered some errors due to passing incorrect navigation callbacks. I also overlooked the fragment factory aspect in AndroidFragment and found this composable better suited