IssueTracker

This happens when fragments use animation whereby it doesn't wait for animations to complete and moves directly to RESUMED state.

The entry's listener to Fragment state does not get attached because it was attaching only if Fragment was in CREATED / STARTED state.

This has been fixed internally and will be available in navigation 2.6.0-alpha07

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

• androidx.navigation:navigation-fragment:2.6.0-alpha07

NavBackStackEntry is still not triggering RESUMED on androidx.navigation:navigation-fragment:2.6.0-alpha09 in certain cases, where after a locale or uiMode change with

AppCompatDelegate.setApplicationLocales
AppCompatDelegate.setDefaultNightMode

Issue can be reproduced with attaching LifecycleObserver to the currentBackStackEntry of a Home fragment like so:

       findNavController().currentBackStackEntry?.lifecycle?.let {
            if (it.currentState.isAtLeast(Lifecycle.State.RESUMED)) {
                Timber.d(Constants.LOG_INFO, "lifecycle.currentState", "resumed")
            } else {
                val testLifecycleObserver = object : DefaultLifecycleObserver {
                    override fun onResume(owner: LifecycleOwner) {
                        Timber.d(Constants.LOG_INFO, "lifecycle.currentState", "onResumed")
                        it.removeObserver(this)
                    }
                }
                it.addObserver(testLifecycleObserver)
            }
        }

After performing a config change as mentioned above on a Settings fragment, upon performing a popBackStack/navigateUp to Home fragment, the DefaultLifecycleObserver's onResume will not be triggered. Issue does not occur if a config change is not performed.

I believe this was actually addressed as part of the Navigation 2.6.0-beta01 release. Can you try that out and see if you can still reproduce?

Problem not fixed for Translations - suggest reopening.

My fix to allow enterTransition to act as if Hold() was working correctly. I don't enterTransition animate at all:

exitTransition = HoldBackground(resources).setDuration(duration)
enterTransition = Slide(Gravity.RIGHT).setDuration(duration)

With HoldBackground looking like this:

class HoldBackground(val resources : Resources) : Transition() {

    init {
        duration = resources.getInteger(android.R.integer.config_mediumAnimTime).toLong()
    }
    var inProgress = false

    @Synchronized
    override fun captureStartValues(transitionValues: TransitionValues) {
        if(inProgress) return
        transitionValues.view.also { exitingView ->
            exitingView.parent.also { fragmentContainer ->
                if(fragmentContainer is View && exitingView.width > 0 && exitingView.height > 0) {
                    inProgress = true
                    val previousBackground = fragmentContainer.background
                    val bitmap = Bitmap.createBitmap(
                        exitingView.width,
                        exitingView.height,
                        Bitmap.Config.ARGB_8888
                    )
                    exitingView.draw(Canvas(bitmap))
                    fragmentContainer.background = BitmapDrawable(resources, bitmap)
                    // Simple animator so timing matches developer animation scales
                    val animator = ValueAnimator.ofInt(0, 1).setDuration(duration)
                    animator.addListener(object : BlankAnimatorListener() {
                        override fun onAnimationEnd(animation: Animator?) {
                            fragmentContainer.background = previousBackground
                            inProgress = false
                        }
                    })
                    animator.start()
                }
            }
        }
    }

    override fun captureEndValues(transitionValues: TransitionValues) {}
}

It's very likely stupidly resource intensive given it's creating a screen size bitmap... but it does happen to work.