IssueTracker

Fix failing PredictiveBackHandler enabled changes

As part of asop/3164566 we attempted to fix an error with
PredictiveBackHandler by closing the internal onBackInstance when the
enabled status changed. This would have worked, except by the time we
made it to the LaunchedEffect the onBackInstance was always null, so we
weren't closing anything.

I believe the cause of this is that `onBackInstance` was a field of a
function and we couldn't reference it across different calls. Because we
needed to change it as part of the backCallback, it also could not be
remembered.

So instead of using the onBackInstance, we can just use the callback
`isEnabled` state directly by passing the callback to the
`OnBackInstance`. This ensures that we only fire the `onBack` callback
when the function is actually enabled.

Test: PredictiveBackHandlerTest, tested and confirmed in sample app
Bug: 365027664
Bug: 340202286
RelNote: "`PredictiveBackHandler` will no longer fire it's callback
after the handler has been disabled. This will fix an issue where
the `NavHost` from Navigation Compose would throw an
`IndexOutOfBoundsException`."

Change-Id: I3f75eb2415f39b914f18cf4b87bf4ed57bb5a483

Files:

• M activity/activity-compose/src/androidTest/java/androidx/activity/compose/PredictiveBackHandlerTest.kt
• M activity/activity-compose/src/main/java/androidx/activity/compose/PredictiveBackHandler.kt

Hash: 1658eca1da25d8092f3cd48806946edcdec73688
Date:  Thu Sep 26 18:15:59 2024