dragAndDropTarget

TextDragAndDropTargetSample

@Sampled
@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,
                )
        }
    }
}

private fun DragAndDropEvent.summary() =
    (0 until toAndroidDragEvent().clipData.itemCount)
        .map(toAndroidDragEvent().clipData::getItemAt)
        .withIndex()
        .joinToString(separator = "\n\n") { (index, clipItem) ->
            val mimeTypes =
                (0 until toAndroidDragEvent().clipData.description.mimeTypeCount).joinToString(
                    separator = ", ",
                    transform = toAndroidDragEvent().clipData.description::getMimeType,
                )
            listOfNotNull(
                    "index: $index",
                    "mimeTypes: $mimeTypes",
                    clipItem.text?.takeIf(CharSequence::isNotEmpty)?.let { "text: $it" },
                    clipItem.htmlText?.takeIf(CharSequence::isNotEmpty)?.let { "html text: $it" },
                    clipItem.uri?.toString()?.let { "uri: $it" },
                    clipItem.intent?.let {
                        "intent: action - ${it.action}; extras size: ${it.extras?.size()}"
                    },
                )
                .joinToString(separator = "\n")
        }