swipeableTopBottom.kt

fun Modifier.swipeableTopBottom(onTop: () -> Unit, onBottom: () -> Unit): Modifier = composed {
    var width by rememberSaveable { mutableStateOf(0f) }
    val swipeableState = rememberSwipeableState(
        SwipeDirection.Initial,
        animationSpec = snap()
    )
    val anchorWidth = remember(width) {
        if (width == 0f) {
            1f
        } else {
            width
        }
    }
    val scope = rememberCoroutineScope()
    if (swipeableState.isAnimationRunning) {
        DisposableEffect(Unit) {
            onDispose {
                when (swipeableState.currentValue) {
                    SwipeDirection.Top -> {
                        onTop()
                    }
                    SwipeDirection.Bottom -> {
                        onBottom()
                    }
                    else -> {
                        return@onDispose
                    }
                }
                scope.launch {
                    swipeableState.snapTo(SwipeDirection.Initial)
                }
            }
        }
    }
    return@composed Modifier
        .onSizeChanged { width = it.width.toFloat() }
        .swipeable(
            state = swipeableState,
            anchors = mapOf(
                0f to SwipeDirection.Top,
                anchorWidth / 2 to SwipeDirection.Initial,
                anchorWidth to SwipeDirection.Bottom,
            ),
            thresholds = { _, _ -> FractionalThreshold(0.3f) },
            orientation = Orientation.Vertical
        )
}

private enum class SwipeDirection(val raw: Int) {
    Top(0),
    Initial(1),
    Bottom(2),
}