Project: platform/frameworks/support
Branch: androidx-main

commit e465976de8f05f0d1db49b4e2887c9f3cd4beab5
Author: Jeremy Woods <jbwoods@google.com>
Date:   Wed Mar 17 17:07:42 2021

    Add OnBackPressedDispatcher observer before NavController observer
   
    If you add a OnBackPressed callback with the NavBackStackEntry as the
    lifecycle owner, if the Activity Lifecycle is STOPPED and STARTED again, the navController callback and NavBackStackEntry callback are readded to the Activity Lifecycle in the wrong order. This means that the new callback will not properly intercept onBackPressed() calls from the system, they will instead be intercepted by NavController.
   
    If an OnBackPressedDispatcher is set, we should remove and readd the
    NavController observer after we add the callback to the dispatcher.
   
    RelNote: "OnBackPressedCallbacks added to a dispatcher with the
    NavBackStackEntry as the LifecycleOwner now properly intercept back
    after the Activity Lifecycle is STOPPED, then STARTED"
    Test: NavControllerTest
    Bug: 182284739
   
    Change-Id: I6acf78848546160eaea7ed700ef8875664a125d0

M       navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M       navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.kt

https://android-review.googlesource.com/1643646

Project: platform/frameworks/support
Branch: androidx-main

commit f231e0f384f9fd2e7a078bfcbeb7768c82c617b1
Author: Jeremy Woods <jbwoods@google.com>
Date:   Wed Mar 17 17:40:05 2021

    Add BackHandler callback with a LifecycleOwner
   
    We need to ensure that the callback from BackHandler remains in the
    proper position in the event of Lifecycle changes.
   
    RelNote: "The BackHandler will now properly intercept back presses in
    the event that the Activity is STOPPED, then STARTED again, and other
    callbacks were added with a LifecycleOwner."
    Test: BackHandlerTest
    Bug: 182284739
   
    Change-Id: I71de6184ba73f56b34de9dcddaf138d98c46417f

M       activity/activity-compose/build.gradle
M       activity/activity-compose/src/androidTest/java/androidx/activity/compose/BackHandlerTest.kt
M       activity/activity-compose/src/main/java/androidx/activity/compose/BackHandler.kt

https://android-review.googlesource.com/1644062

Project: platform/frameworks/support
Branch: androidx-main

commit d1d6f89ba90be8e7fba193570b427f52ec98f57a
Author: Jeremy Woods <jbwoods@google.com>
Date:   Wed Mar 31 09:40:42 2021

    Make nav compose depend on Navigation 2.3.5
   
    Upgrading to the latest Navigation version to take advantage of fixed
    bugs, (particularly around OnBackPressedDispatcher and lifecycles
    b/182284739).
   
    RelNote: "Navigation-compose now depends on Navigation version `2.3.5`"
    Test: ./gradlew bOS
    Change-Id: I7e63b32c93deaee60b1d5e132d3fa255c3ba85e2

M       navigation/navigation-compose/build.gradle

https://android-review.googlesource.com/1660640

does not work for me on '2.4.2'

        val navController: NavHostController = rememberNavController()
        HomeNavHost(navController = navController)

        BackHandler(true) {
            // code doesnt get called here
        }

I got similar issue, after I run launcher (exp: select document), BackHandler no longer triggers

    BackHandler{
        action.onBack()
    }

to solve BackHandler no longer triggers after i run launcher, i am using this

@Composable
fun BaseBackHandler(onBackHandler: () -> Unit = {}) {
    var refreshBackHandler by rememberSaveable { mutableStateOf(false) }
    OnLifecycleEvent { _, event ->
        when (event) {
            Lifecycle.Event.ON_PAUSE -> {
                refreshBackHandler = false
            }
            Lifecycle.Event.ON_RESUME -> {
                refreshBackHandler = true
            }
            else -> {}
        }
    }
    if (refreshBackHandler) {
        BackHandler {
            onBackHandler()
        }
    }
}