如何在 Jetpack compose 中导航到其他屏幕时进行多个呼叫

Question

在我的应用程序中，每当我们导航到另一个屏幕时，我都会添加动画：

  NavHost(
    navController = navController,
    startDestination = startDestination,
    enterTransition = {
      slideIntoContainer(
        towards = AnimatedContentTransitionScope.SlideDirection.Companion.Left,
        animationSpec = tween(TRANSITION_ANIMATION_DURATION)
      )
    },
    exitTransition = {
      slideOutOfContainer(
        towards = AnimatedContentTransitionScope.SlideDirection.Companion.Left,
        animationSpec = tween(TRANSITION_ANIMATION_DURATION)
      )
    },
    popEnterTransition = {
      slideIntoContainer(
        towards = AnimatedContentTransitionScope.SlideDirection.Companion.Right,
        animationSpec = tween(TRANSITION_ANIMATION_DURATION)
      )
    },
    popExitTransition = {
      slideOutOfContainer(
        towards = AnimatedContentTransitionScope.SlideDirection.Companion.Right,
        animationSpec = tween(TRANSITION_ANIMATION_DURATION)
      )
    }
  ) {

    composable(route = AppDestination.Recent.destination) { nav ->
      AbcRoute(navController = navController, entry = nav)
    }
}

在路线中：

@Composable
fun AbcRoute(
  navController: NavController,
  entry: NavBackStackEntry,
) {

  val objectA = entry.arguments?.getString(AppDestination.Abc.objectA)?.let {
    Json.decodeFromString<A>(it)
  } ?: return
 
  val viewModel = hiltViewModel<AbcViewModel>()

  val lifecycle = LocalLifecycleOwner.current.lifecycle

  val state = viewModel.enhanceState.collectAsStateWithLifecycle()
  LaunchedEffect(lifecycle) {
    viewModel.initialize(objectA)
  }

在 ViewModel 中，每次用户打开屏幕时我都会开始调用 API。 但问题是，因为它有动画，所以屏幕多次重组 -> 多次调用 API。

• 我将请求添加到 ViewModel 范围，它取消了，但有时调用仍然成功，这看起来不是一个好主意。我们有正确的方法吗？

谢谢！

Answer 1

我看到您正在使用

lifecycle

作为

LaunchedEffect

的钥匙。大多数时候，如果我只想在 compose 中执行一次代码，我会使用

LaunchedEffect(Unit){}