如何检测撰写按钮上的运动事件？

Question

我正在尝试创建一个图标按钮，它在点击时调用 lambda，但如果用户按下按钮并按住它，那么 lambda 也应该以固定的时间间隔连续调用。

@Composable
fun MyIconButton(
    someLambda: () -> Unit
) {
    IconButton(onClick = someLambda) {
        Icon(
            // painter and content description
        )
    }
}

我想要的是当用户按下按钮时，someLambda 应该被调用（工作正常）。此外，我还想重复调用 someLambda（两次调用之间有 500 毫秒的间隔），直到用户释放按钮。

基本上我想要的是检测诸如 KeyUp 和 KeyDown 事件之类的东西。

如何实现？

Answer 1

我会在明天更新答案，但现在，这应该适合您的用例

Modifier.pointerInput(Unit) {
    detectTapGestures(
        onPress = { /* Called when the gesture starts */ },
        onDoubleTap = { /* Called on Double Tap */ },
        onLongPress = { /* Called on Long Press */ },
        onTap = { /* Called on Tap */ }
    )
}

Answer 2

您可以为此使用 Modifier.pointerInpteropFilter：

var job by remember {
    mutableStateOf<Job?>(null)
}
val scope = rememberCoroutineScope()

Icon(
    imageVector = Icons.Filled.Favorite,
    modifier = Modifier
        .requiredSize(96.dp)
        .pointerInteropFilter {
            when (it.action) {
                MotionEvent.ACTION_DOWN -> {
                    job = scope.launch {
                        while (true) {
                            // trigger event
                            Log.d("foo", "Trigger event")
                            delay(500L)
                        }
                    }
                }
                MotionEvent.ACTION_UP,
                MotionEvent.ACTION_CANCEL -> {
                    job?.cancel()
                    job = null
                }
            }
            true
        },
    contentDescription = "Sample icon"
)

另一个解决方案是使用 Modifier.pointerInput:

val scope = rememberCoroutineScope()
Icon(
    imageVector = Icons.Filled.Favorite,
    modifier = Modifier
        .requiredSize(96.dp)
        .pointerInput(Unit) {
            while (true) {
                awaitPointerEventScope {
                    awaitFirstDown()
                    val job = scope.launch {
                        while (true) {
                            // trigger event
                            Log.d("foo", "Trigger event")
                            delay(500L)
                            Log.d("foo", "After delay")
                        }
                    }
                    waitForUpOrCancellation()
                    job.cancel()
                }
            }
        },
    contentDescription = "Sample icon"
)

Answer 3

我在 Icon 上使用 Modifier.pointerInput 解决了问题。

Modifier.pointerInput(true) {
    detectTapGestures(onPress = {
        coroutineScope {
            val job = launch {
                while (true) {
                    // Invoke lambda
                    delay(500)
                }
            }
            tryAwaitRelease()
            job.cancel()
        }
    })
}

根据文档，

onPress is called when the press is detected and PressGestureScope.tryAwaitRelease can be used to detect when pointers have released or the gesture was canceled.

如何检测撰写按钮上的运动事件？

How to detect motion events on a compose button?

android

kotlin

android-jetpack-compose

android-jetpack-compose-text