Dispose Screens only when transition ends

[DevSrSouza]

ISSUE SOLVED: #106

To use this new behavior you have to disable disposeBehavior.disposeSteps and use the ScreenTransition.disposeScreenAfterTransitionEnd = true

Navigator(
    ....
    disposeBehavior = NavigatorDisposeBehavior(disposeSteps = false)
) {
    ScreenTransition(
       navigator = it,
       ...,
       disposeScreenAfterTransitionEnd = true
    )
}

[shpasha]

I think we should collect all navigator items changes.

Case:

We have navigator with transitions, it's stack: A -> B -> C.
User presses "back" 2 times quickly, so the stack now: A.

IMPORTANT NOTE: the transition was not completed during the entire stack change.

After all these actions, screens B, C should be disposed. But as i understand from your solution, only screen B will be disposed

[shpasha]

So because of this case i collect all navigator item changes: https://github.com/adrielcafe/voyager/pull/427/files#diff-b8d3186fe9802c02964e8e565ad0ae0195d79ae7e74854c8b3c256ba68e572daR70

[shpasha]

So my idea is simple:

Collect all screens created during transitions (because during slow transition crazy user can navigate to and from different screens). After completion of transition compare collected screens with idled stack. Then dispose screens that are no longer in the navigation stack

[DevSrSouza]

Yeh, I have being testing exactly that previously and I was able to reproduce it! I will try your suggestion.

[DevSrSouza]

@shpasha I have bring your solution instead of previousItems, I have tested here and it seems pretty good. Can you test your use cases as well?

This way we can let as experimental and rethink if a Channel with Local Composition is a better solution in the future, for now, I think let this responsibility to the actual Transition component is safer and makes more sense and also, does not do any changes on Navigator Core

[shpasha]

Actually, i don't understand why I wrote this line 😄

I think we can get rid of ScreenData without any problems. Just save Screen only

[shpasha]

I suggest changing the condition a little:

if (this.transition.targetState == this.transition.currentState && disposeScreenAfterTransitionEnd) {
 ...
}

and get rid of disposeScreenAfterTransitionEnd check in LaunchedEffect

[shpasha]

suggest to wrap 142-148 lines in if condition if (disposeScreenAfterTransitionEnd) { ... }

[shpasha]

@DevSrSouza thanks!