IssueTracker

Is this specific to navigation? Or can this be reproduced with another other Composable component?

It only happens inside of a NavHost. So, yes, it seems to be specific to navigation.

This was caused by the fix to b/182284739 which made BackHandler lifecycle aware. The problem here is that the NavController registers its lifecycle and added an observer to the Activity Lifecycle in composition while the BackHandler registers its observer on the Activity Lifecycle in a DisposbleEffect. This means that the NavController will always get Lifecycle callbacks before the BackHandler, so the components listening the the NavController's lifecycle (like the NavBackStackEntry) will always get their Lifecycle callbacks before the BackHandler as well.

This should be addressed by work coming in 2.7 to integrate the BackHandler into the NavHost.

This has been fixed internally and will be available in Navigation 2.7.0-beta01.

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

• androidx.navigation:navigation-compose:2.7.0-beta01

I wouldn't say this is fixed. If you add a back-callback in the activity which is lifecycle aware, and then background->foreground the app, the activity back-callback will be put on top of the callback pile. This leads to that any BackHandler in your composable will NOT be triggered.

The best workaround I have for now is to use the non-lifecycle aware function in the activity.

class MainActivity : FragmentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        
        // open fragment which hoists the composables
        ...

        if (savedInstanceState == null) {
             onBackPressedDispatcher.addCallback(onBackPressedCallback = someBackHandling())  
            // onBackPressedDispatcher.addCallback(owner = this, onBackPressedCallback = someBackHandling)  // not this one
        }
    }

https://developer.android.com/jetpack/androidx/releases/navigation#2.7.0-beta01 :

Bug Fixes : NavHost in Navigation Compose now correctly intercepts system back calls even after the Activity has been STOPPED and RESUMED.

It works fine for me.

Re comment#14 - please file a new issue with a project that reproduces your problem.

Note that you should never, ever be calling navController.popBackStack() in your own BackHandler as Navigation must be the only one handling its own back stack with the system back button so that Predictive Back works correctly in the future.

These changes broke our use case to override back handling in navigation library for closing the menu drawer. Please see more details in the issue I've reported.

I believe this is still an issue even without using NavHost like mentioned in comment #16. I filed a new issue here

Thanks for reporting this, a change is submitted (aosp/3393546) and will be available in the next canary builds of the emulator to correctly give an error for zero device cases. I'll close this one now as the booting issue is resolved with a driver update.

Thank you for your patience while our engineering team worked to resolve this issue. A fix for this issue is now available in:

• Android Emulator 35.3.11 Stable

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

Thank you for taking the time to submit feedback — we really appreciate it!

Further fixes for this issue are now available in:

• Android Emulator 35.4.5 Canary

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.