IssueTracker

Can you attach a sample project that reproduces your issue?

I'm experiencing this issue in a commercial non-open source project so I'd have to provide extracted code fragments. The menu file for instance looks similar to this:

<menu>
    <item
        android:id="@+id/destination_one" />

    <item
        android:id="@+id/destination_two" />

    <item
        android:id="@+id/destination_three" />

    <item
        android:id="@+id/destination_four" />
</menu>

The menu item ids match the top level destination ids as for instance destination_one as required by the NavigationUI library.

The xml layout file of the main activity (there is only one activity) looks pretty much like this:

<androidx.coordinatorlayout.widget.CoordinatorLayout>

    <androidx.constraintlayout.widget.ConstraintLayout>

        <androidx.fragment.app.FragmentContainerView
            android:id="@+id/navigation_host_fragment"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            app:defaultNavHost="true"
            app:layout_constraintBottom_toTopOf="@id/bottom_navigation"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:navGraph="@navigation/main_navigation" />

        <com.google.android.material.bottomnavigation.BottomNavigationView
            android:id="@+id/bottom_navigation"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/navigation_host_fragment"
            app:menu="@menu/main_menu" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

The main_navigation is the first navigation graph I posted in the original post. The behavior I described above only affects the first bottomNavigation item which corresponds to the top level navGraph's startDestination.

Yeah, what we're looking for is a full project (i.e., take a brand new project in Android Studio, put your few bits of code in, and make sure your problem reproduces) as there are a lot of little pieces that can make a difference here.

https://github.com/postfixNotation/NavigationUI

Of course the logic of my project is more sophisticated but this reproduces the issue quite well. If you click the first BottomNavigation item N times you need N+1 system back navigation triggers to leave the app.

So first, we plan to get rid of these APIs in the future. The only behavior for NavigationUI will be to always save and restore the state of the back stack. Luckily, NavigationUI is purposely built only on publicly available APIs so you could always copy our code and make your custom adjustments for whatever your desired behavior is.

The source of the bug is here in NavController. Since we are navigating to the graph and the currentDestination is the start destination on the graph their ids don't match and we never actually do the singleTop operation causing multiple of the same destination to be added to the back stack.

We need to add a fix to ensure we take into account the proper destination on our side, but as I mentioned those APIs will go away in the future. So if you wanted to proactively create your own API, you could make your API navigate directly to the start destination instead of the graph. That would allow you to not wait on our release and ensure you always have your desired behavior going forward.

Thanks a lot for your help! I basically removed the first embedded graph by moving the code directly into the topmost navGraph and as you said, navigate directly to the start destination. As far as I can tell, it seems to work now.

This has been fixed internally and will be available in Navigation 2.6.0-alpha05

The following release(s) address this bug.It is possible this bug has only been partially addressed:

• androidx.navigation:navigation-common:2.6.0-alpha05
• androidx.navigation:navigation-runtime:2.6.0-alpha05

I'm still experiencing this issue in my app as of version 2.8.4. Seemingly at random I'll see a scale animation from the top left instead of my custom one.

Feel free to reference it here: https://github.com/t895/DNSNet/blob/30e0b1acbbbb1459a7953c7b69c05aca588817c9/app/src/main/kotlin/dev/clombardo/dnsnet/ui/Home.kt#L646

Project: platform/frameworks/support
Branch: androidx-main
Author: Jeremy Woods <jbwoods@google.com>
Link:      https://android-review.googlesource.com/3393408

Stop incorrect scaling animation when using NavHost

Stop incorrect scaling animation when using NavHost 
 
There is a case where if you can trigger a navigate call right before the 
LaunchEffect that is responsible for managing the end of the 
AnimatedContent's transition is called, you will get an incorrect scale 
animation. 
 
The reason for this is that the call to navigate adds the proper entries 
to the visibleEntries list and then the LaunchedEffect immediately 
remove it. Then when the AnimatedContent attempts to find this removed 
entry it is not there and AnimatedContent thinks it is animated from 
nothing and just scales from a blank screen. 
 
Since this is an interrupt case the the AnimatedContent has not actually 
finsihed with transition, we should not be hitting the `LaunchedEffect` 
and marking the transition complete at all, but that needs to be 
addressed by the Animation library so this change provides a workaround 
in the mean time that just keeps from incorrectly marking the visible 
entry's transition as complete. 
 
RelNote: "Added a workaround to fix an issue that caused an unexpected 
scale animation when using Navigation Compose." 
Test: tested in sample app 
Bug: 353294030 
 
Change-Id: I26cb142affb046e94b34b9501e5405ddcf276fcf

Project: platform/frameworks/support
Branch: androidx-main
Author: Jeremy Woods <jbwoods@google.com>
Link:      https://android-review.googlesource.com/3393411

Avoid race condition for transitions in NavHost

Avoid race condition for transitions in NavHost 
 
This is cleaning up the code added in aosp/3393408. The issue is caused 
by a race condition where the previous animation has ended but the 
current animation has yet to start because `animateTo` is still waiting 
to acquire the `mutatorMutex`. 
 
We need to verify that what `AnimatedContent` believes is the 
`targetState` is the same thing that is on top of the back stack before 
we mark the entries as complete. 
 
RelNote: "Fix an issue that caused an unexpected scale animation when 
using Navigation Compose." 
Test: tested extensively in sample app 
Bug: 353294030 
 
Change-Id: I480f4d89ffc7e2dfa536a592a8fc7b6c759be1a4

This has been fixed internally and will be available in the Navigation 2.8.5 release.

The following release(s) address this bug.It is possible this bug has only been partially addressed:

• androidx.navigation:navigation-compose:2.8.5

Seems solid on my end

The following release(s) address this bug.It is possible this bug has only been partially addressed:

• androidx.navigation:navigation-compose:2.9.0-alpha05