android - 如何在 Jetpack Compose 中通过单击按钮显示 snackbar

Question

我想在 Jetpack Compose 中显示带有按钮 onclick 的 snackbar
我试过这个

Button(onClick = {
    Snackbar(action = {}) {
        Text("hello")
    }
} 

但是 AS 说“@Composable 调用只能在 @Composable 函数的上下文中发生”
你能给我一个很好的程序吗？
我希望它可以在 Button.onclick() 中运行

Answer 1

你需要两件事:

SnackbarHostState - 它将管理您的 Snackbar 的状态
(您通常会从 ScaffoldState 获得)

CoroutineScope - 负责showing您的 Snackbar

@Composable
fun SnackbarDemo() {
  val scaffoldState = rememberScaffoldState() // this contains the `SnackbarHostState`
  val coroutineScope = rememberCoroutineScope()

  Scaffold(
        modifier = Modifier,
        scaffoldState = scaffoldState // attaching `scaffoldState` to the `Scaffold`
    ) {
        Button(
            onClick = {
                coroutineScope.launch { // using the `coroutineScope` to `launch` showing the snackbar
                    // taking the `snackbarHostState` from the attached `scaffoldState`
                    val snackbarResult = scaffoldState.snackbarHostState.showSnackbar(
                        message = "This is your message",
                        actionLabel = "Do something."
                    )
                    when (snackbarResult) {
                        Dismissed -> Log.d("SnackbarDemo", "Dismissed")
                        ActionPerformed -> Log.d("SnackbarDemo", "Snackbar's button clicked")
                    }
                }
            }
        ) {
            Text(text = "A button that shows a Snackbar")
        }
    }
}