android compose Material3中的Snackbar在@Composable注解函数中不生效？

Question

我参照官方示例，在class MainActivity的override fun onCreate函数中，成功运行起了Snackbar，代码如下：

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val snackbarHostState = remember { SnackbarHostState() }
        val scope = rememberCoroutineScope()
        setContent {
            AliyouyuTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    Scaffold(
                        snackbarHost = { SnackbarHost(snackbarHostState) },
                        floatingActionButton = {
                            var clickCount by remember { mutableStateOf(0) }
                            ExtendedFloatingActionButton(
                                onClick = {
                                    // show snackbar as a suspend function
                                    scope.launch {
                                        snackbarHostState.showSnackbar(
                                            "Snackbar # ${++clickCount}"
                                        )
                                    }
                                }
                            ) { Text("Show snackbar") }
                        },
                        content = { innerPadding ->
                            Text(
                                text = "Body content",
                                modifier = Modifier
                                    .padding(innerPadding)
                                    .fillMaxSize()
                                    .wrapContentSize()
                            )
                        }
                    )
                }
            }
        }
    }
}

但我分离业务代码到独立的函数中时，却无论如何都无法show一个snackbar：

@SuppressLint("UnusedMaterial3ScaffoldPaddingParameter")
@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun LoginForm(
    modifier: Modifier = Modifier,
) {
    val snackbarHostState = remember { SnackbarHostState() }
    val scope = rememberCoroutineScope()

    Scaffold(
        modifier = modifier,
    ) {

        Column(
            horizontalAlignment = Alignment.CenterHorizontally,
            modifier = modifier,
        ) {
            Text(
                text = "title",
                style = MaterialTheme.typography.bodyMedium,
                color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.6f),
                textAlign = TextAlign.Center,
                modifier = Modifier.padding(top = 64.dp, bottom = 12.dp)
            )

            Button(
                onClick = {
                    scope.launch {
                        Log.d("scope.launch", "测试")
                        snackbarHostState.showSnackbar(
                            message = "Snackbar",
                            actionLabel = "Action",
                        )
                    }
                },
                modifier = Modifier
                    .fillMaxWidth()
                    .padding(top = 28.dp, bottom = 3.dp)
            ) {
                Text(
                    text = "登录",
                    style = MaterialTheme.typography.titleSmall
                )
            }

        }

    }

}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            AliyouyuTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    LoginScreen()
                }
            }
        }
    }
}

已经用google搜了大半天了，依然没有任何头绪，还忘高手解答。