Hi everyone .. Im Using Voyager as my Navigation .. However i cant swipe to go back on ios target .....

# compose-ios

[Angga Ardinata]

Hi everyone ..
Im Using Voyager as my Navigation ..
However i cant swipe to go back on ios target .. is there a way or sample repo to implement back gesture on iosApp ? thank you ..

[Konstantin Tskhovrebov]

cc @SrSouza

[mangubatrj]

same here

[Angga Ardinata]

im able to imitate back gesture manually with something like this

abstract class BaseScreen : Screen, BaseScreenContent, ScreenLifecycleOwner {

    @Composable
    override fun Content() {
        val navigator = LocalNavigator.currentOrThrow
        var offsetState by remember { mutableFloatStateOf(0f) }
        Box(
            modifier = Modifier.background(Color.White)
        ) {
            ScreenContent()
            if (Platform.os == PlatformOS.iOS){
                Box(
                    modifier = Modifier
                        .fillMaxHeight()
                        .width(20.dp)
                        .pointerInput(Unit){
                            detectHorizontalDragGestures(
                                onDragEnd = {
                                    if (offsetState > 100) {
                                        if (navigator.items.size > 1) navigator.pop()
                                    }
                                    offsetState = 0f
                                }
                            ) { _, dragAmount ->
                                if (offsetState < 0) return@detectHorizontalDragGestures
                                offsetState += dragAmount
                            }
                        }
                )
            }
        }
    }
}

private interface BaseScreenContent {
    @Composable
    fun ScreenContent()
}

[mangubatrj]

@Angga Ardinata wow nice! I will try this. Did you only apply this to a BaseScreen and does that work for all? or you apply to each screen?

[Angga Ardinata]

How do you create a new screen ? If just

class HomeScreen : Screen {}

Change the implementation of Screen with BaseScreen

[Angga Ardinata]

To all of your screen

[mangubatrj]

Right now I dont have a BaseScreen yet

[mangubatrj]

but okay I will add that then

[Angga Ardinata]

I will not work like ios back gesture where you can peek previous screen .. bit for me atleast user can goback with swipe 😁

[Angga Ardinata]

Voyager still developing this feature

[mangubatrj]

ahh yes that is all I need as well actually 😄

[mangubatrj]

thank you very much @Angga Ardinata will try this on my end

[Angga Ardinata]

https://github.com/adrielcafe/voyager/issues/144 .. here the issue for back gesture

[mangubatrj]

hello @Angga Ardinata just want let you know I managed to implement the back gesture thanks to your help. Hopefully voyager adds the peek previous screen but your solution was a great alternative as well! 🙇

[Angga Ardinata]

@mangubatrj Wow glad that im actually helping someone with my limited knowledge

[SrSouza]

I have not being able to contribute to Voyager lately, but PR are welcome always.
Suggestion folks, instead of using BaseScreen you folks could just add this component to the main Navigation Content.

Example:

Navigator(...) { navigator ->
   Box(..) {
     CurrentScreen()
     if (Platform.os == PlatformOS.iOS){
        ...
     }
   }
}

About previous screen peek, I need to validate about recomposition of it, but, Voyager Stack is built with SnapshotStateList, so, in practice, something like this:

val previousScreen = remember(navigator) {
  derivedStateOf {
    navigator.toList().getOrNull(navigator.size - 2)
  }
}

But if this does not work properly we could easily add peekPreviousItem on it.

[SrSouza]

I did share a implementation from PreCompose that I manage to make it work on Voyager, check it out:
https://github.com/adrielcafe/voyager/issues/144#issuecomment-1763186873

[mangubatrj]

Thank you @SrSouza will definitely check this out! ❤️