detectVerticalDragGestures

suspend fun PointerInputScope.detectVerticalDragGestures(
    onDragStart: (Offset) -> Unit = {},
    onDragEnd: () -> Unit = {},
    onDragCancel: () -> Unit = {},
    onVerticalDrag: (change: PointerInputChange, dragAmount: Float) -> Unit,
)

Gesture detector that waits for pointer down and touch slop in the vertical direction and then calls onVerticalDrag for each vertical drag event. It follows the touch slop detection of awaitVerticalTouchSlopOrCancellation, but will consume the position change automatically once the touch slop has been crossed.

onDragStart called when the touch slop has been passed and includes an Offset representing the last known pointer position relative to the containing element. The Offset can be outside the actual bounds of the element itself meaning the numbers can be negative or larger than the element bounds if the touch target is smaller than the ViewConfiguration.minimumTouchTargetSize.

onDragEnd is called after all pointers are up and onDragCancel is called if another gesture has consumed pointer input, canceling this gesture.

This gesture detector will coordinate with detectHorizontalDragGestures and awaitHorizontalTouchSlopOrCancellation to ensure only vertical or horizontal dragging is locked, but not both.

Example Usage:

Code Examples

DetectVerticalDragGesturesSample

@Composable
fun DetectVerticalDragGesturesSample() {
    val offsetX = remember { mutableStateOf(0f) }
    val offsetY = remember { mutableStateOf(0f) }
    var height by remember { mutableStateOf(0f) }
    Box(Modifier.fillMaxSize().onSizeChanged { height = it.height.toFloat() }) {
        Box(
            Modifier.offset { IntOffset(offsetX.value.roundToInt(), offsetY.value.roundToInt()) }
                .fillMaxWidth()
                .height(50.dp)
                .background(Color.Blue)
                .pointerInput(Unit) {
                    detectVerticalDragGestures { _, dragAmount ->
                        val originalY = offsetY.value
                        val newValue = (originalY + dragAmount).coerceIn(0f, height - 50.dp.toPx())
                        offsetY.value = newValue
                    }
                }
        )
    }
}