Bottom sheet

bottomsheet.kt

enum class States {
    EXPANDED,
    COLLAPSED
}

@ExperimentalMaterialApi
@Composable
fun FullHeightBottomSheet(
    header: @Composable () -> Unit,
    body: @Composable () -> Unit
) {
    val swipeableState = rememberSwipeableState(initialValue = States.EXPANDED)
    val scrollState = rememberScrollState()

    BoxWithConstraints {
        val constraintsScope = this
        val maxHeight = with(LocalDensity.current) {
            constraintsScope.maxHeight.toPx()
        }

        val connection = remember {
            object : NestedScrollConnection {

                override fun onPreScroll(
                    available: Offset,
                    source: NestedScrollSource
                ): Offset {
                    val delta = available.y
                    return if (delta < 0) {
                        swipeableState.performDrag(delta).toOffset()
                    } else {
                        Offset.Zero
                    }
                }

                override fun onPostScroll(
                    consumed: Offset,
                    available: Offset,
                    source: NestedScrollSource
                ): Offset {
                    val delta = available.y
                    return swipeableState.performDrag(delta).toOffset()
                }

                override suspend fun onPreFling(available: Velocity): Velocity {
                    return if (available.y < 0 && scrollState.value == 0) {
                        swipeableState.performFling(available.y)
                        available
                    } else {
                        Velocity.Zero
                    }
                }

                override suspend fun onPostFling(
                    consumed: Velocity,
                    available: Velocity
                ): Velocity {
                    swipeableState.performFling(velocity = available.y)
                    return super.onPostFling(consumed, available)
                }

                private fun Float.toOffset() = Offset(0f, this)
            }
        }

        Box(
            Modifier
                .swipeable(
                    state = swipeableState,
                    orientation = Orientation.Vertical,
                    anchors = mapOf(
                        0f to States.EXPANDED,
                        maxHeight to States.COLLAPSED,
                    )
                )
                .nestedScroll(connection)
                .offset {
                    IntOffset(
                        0,
                        swipeableState.offset.value.roundToInt()
                    )
                }
        ) {
            Column(
                Modifier
                    .fillMaxHeight()
                    .background(Color.White)
            ) {
                header()
                Box(
                    Modifier
                        .fillMaxWidth()
                        .verticalScroll(scrollState)
                ) {
                    body()
                }
            }
        }
    }
}

Oh Sorry, Got it, Didn't see the extension function created below.

Hello, How can I make it so that I can move the bottom sheet only for the area with LazyColumn?

If you want swipeable behavior to occur only when interacting with the actual bottom sheet content Modifier.offset() should be before Modifier.swipeable().

Modifier
    .offset {
        IntOffset(
            0,
            swipeableState.offset.value.roundToInt()
        )
    }
    .swipeable(
        state = swipeableState,
        orientation = Orientation.Vertical,
        anchors = mapOf(
            0f to States.EXPANDED,
            maxHeight to States.COLLAPSED,
        )
    )
    .nestedScroll(connection)

This looks great. One issue I've noticed though is that when the bottom sheet is expanded and you scroll the content, it doesn't use momentum scrolling.

If you want swipeable behavior to occur only when interacting with the actual bottom sheet content Modifier.offset() should be before Modifier.swipeable().

Modifier
    .offset {
        IntOffset(
            0,
            swipeableState.offset.value.roundToInt()
        )
    }
    .swipeable(
        state = swipeableState,
        orientation = Orientation.Vertical,
        anchors = mapOf(
            0f to States.EXPANDED,
            maxHeight to States.COLLAPSED,
        )
    )
    .nestedScroll(connection)

Life Saver. Thank you!!

This is amazing @arcadefire 🪨 ⭐ !!