【Android Compose】Compose中如何delay一个事件

我们可以通过这几种方式Hander.postDelayed() CoroutineScope LaunchedEffect

• 通过rememberCoroutineScope(推荐)

val coroutineScope = rememberCoroutineScope()  // in top of Composable
// ...
onTap = {
    // Handle tap gesture on the key
    isPopupVisible.value = true
    coroutineScope.launch{
        delay(250)
        isPopupVisible.value = false
    }
    // ...
}

• 通过LaunchedEffect

Composable
fun PopupScreen(
    label: String,
    isVisible: Boolean,
    onHide: () -> Unit
) {
    val popupWidth = dimensionResource(id = R.dimen.key_width)
    val popupHeight = dimensionResource(id = R.dimen.key_height)
    val cornerSize = dimensionResource(id = R.dimen.key_borderRadius)

    LaunchedEffect(Unit){
        delay(250)
        onHide()
    }

    // ...
}

在调用的 Composable 中，相应地对回调做出反应：onHide

if (key.shouldShowPopUp) {
    // Display a pop-up screen if Clicked
    PopupScreen(
        label = popUpLabel,
        isVisible = isPopupVisible.value,
        onHide = { isPopupVisible.value = false }
    )
}

https://developer.android.com/develop/ui/compose/side-effects

• handler(不推荐,有内存泄漏的风险)