awaitDragOrCancellation

suspend fun AwaitPointerEventScope.awaitDragOrCancellation(
    pointerId: PointerId
): PointerInputChange?

Reads pointer input events until a drag is detected or all pointers are up. When the final pointer is raised, the up event is returned. When a drag event is detected, the drag change will be returned. Note that if pointerId has been raised, another pointer that is down will be used, if available, so the returned PointerInputChange.id may differ from pointerId. If the position change in the any direction has been consumed by the PointerEventPass.Main pass, then the drag is considered canceled and null is returned. If pointerId is not down when awaitDragOrCancellation is called, then null is returned.

Example Usage:

Code Examples

AwaitDragOrCancellationSample

@Composable
fun AwaitDragOrCancellationSample() {
    val offsetX = remember { mutableStateOf(0f) }
    val offsetY = remember { mutableStateOf(0f) }
    var size by remember { mutableStateOf(Size.Zero) }
    Box(Modifier.fillMaxSize().onSizeChanged { size = it.toSize() }) {
        Box(
            Modifier.offset { IntOffset(offsetX.value.roundToInt(), offsetY.value.roundToInt()) }
                .size(50.dp)
                .background(Color.Blue)
                .pointerInput(Unit) {
                    awaitEachGesture {
                        val down = awaitFirstDown()
                        var change =
                            awaitTouchSlopOrCancellation(down.id) { change, over ->
                                val original = Offset(offsetX.value, offsetY.value)
                                val summed = original + over
                                val newValue =
                                    Offset(
                                        x = summed.x.coerceIn(0f, size.width - 50.dp.toPx()),
                                        y = summed.y.coerceIn(0f, size.height - 50.dp.toPx()),
                                    )
                                change.consume()
                                offsetX.value = newValue.x
                                offsetY.value = newValue.y
                            }
                        while (change != null && change.pressed) {
                            change = awaitDragOrCancellation(change.id)
                            if (change != null && change.pressed) {
                                val original = Offset(offsetX.value, offsetY.value)
                                val summed = original + change.positionChange()
                                val newValue =
                                    Offset(
                                        x = summed.x.coerceIn(0f, size.width - 50.dp.toPx()),
                                        y = summed.y.coerceIn(0f, size.height - 50.dp.toPx()),
                                    )
                                change.consume()
                                offsetX.value = newValue.x
                                offsetY.value = newValue.y
                            }
                        }
                    }
                }
        )
    }
}