dragAndDropTarget

Compose Modifier

Common

fun Modifier.dragAndDropTarget(
    shouldStartDragAndDrop: (startEvent: DragAndDropEvent) -> Boolean,
    target: DragAndDropTarget,
): Modifier

A modifier that allows for receiving from a drag and drop gesture.

Learn how to use Modifier.dragAndDropTarget to receive drag and drop events from inside your app or from other apps:

All drag and drop target modifiers in the hierarchy will be given an opportunity to participate in a given drag and drop session via shouldStartDragAndDrop.

Parameters


shouldStartDragAndDrop	Allows the Composable to decide if it wants to receive from a given drag and drop session by inspecting the `DragAndDropEvent` that started the session.
target	The `DragAndDropTarget` that will receive events for a given drag and drop session.

Code Examples

TextDragAndDropTargetSample

@Composable
fun TextDragAndDropTargetSample(
    eventSummary: String?,
    onDragAndDropEventDropped: (DragAndDropEvent) -> Unit,
) {
    val validMimeTypePrefixes = remember {
        setOf(ClipDescription.MIMETYPE_TEXT_INTENT, "image/", "text/", "video/", "audio/")
    }
    var backgroundColor by remember { mutableStateOf(Color.Transparent) }
    val dragAndDropTarget = remember {
        object : DragAndDropTarget {
            override fun onStarted(event: DragAndDropEvent) {
                backgroundColor = Color.DarkGray.copy(alpha = 0.2f)
            }
            override fun onDrop(event: DragAndDropEvent): Boolean {
                onDragAndDropEventDropped(event)
                return true
            }
            override fun onEnded(event: DragAndDropEvent) {
                backgroundColor = Color.Transparent
            }
        }
    }
    Box(
        modifier =
            Modifier.fillMaxSize()
                .dragAndDropTarget(
                    shouldStartDragAndDrop = accept@{ startEvent ->
                            val hasValidMimeType =
                                startEvent.mimeTypes().any { eventMimeType ->
                                    validMimeTypePrefixes.any(eventMimeType::startsWith)
                                }
                            hasValidMimeType
                        },
                    target = dragAndDropTarget,
                )
                .background(backgroundColor)
                .border(width = 4.dp, color = Color.Magenta, shape = RoundedCornerShape(16.dp))
    ) {
        when (eventSummary) {
            null -> Text(modifier = Modifier.align(Alignment.Center), text = "Drop anything here")
            else ->
                Text(
                    modifier =
                        Modifier.padding(horizontal = 16.dp, vertical = 24.dp)
                            .verticalScroll(rememberScrollState()),
                    text = eventSummary,
                )
        }
    }
}