相关疑难解决方法(0)

这是导致无限重组问题的代码

主要活动

class MainActivity : ComponentActivity() {
    
     override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        
        setContent {
                val navController = rememberNavController()
                val viewModel : MainViewModel by viewModel()
                val state by viewModel.state.observeAsState()

                NavHost(navController = navController, startDestination = "firstScreen") {
                    composable("firstScreen") { FirstScreen(
                        navigate = {
                        navController.navigate("secondScreen")
                    }, updateState = {
                            viewModel.getState()
                       },
                       state

                    )}

                    composable("secondScreen") { SecondScreen() }
                }
        }
    }
}

视图模型

class MainViewModel : ViewModel() {

    //var state = MutableStateFlow(0)

    private val _state = MutableLiveData(0)
    val state: LiveData<Int> = _state

    fun …

我正在尝试Navigation使用单个活动和多个Composable屏幕来实现。

这是我的NavHost：

@Composable
@ExperimentalFoundationApi
fun MyNavHost(
    modifier: Modifier = Modifier,
    navController: NavHostController = rememberNavController(),
    startDestination: String = HOME.route,
    viewModelProvider: ViewModelProvider,
    speech: SpeechHelper
) = NavHost(
    modifier = modifier,
    navController = navController,
    startDestination = startDestination
) {
    composable(route = HOME.route) {
        with(viewModelProvider[HomeViewModel::class.java]) {
            HomeScreen(
                speech = speech,
                viewModel = this,
                modifier = Modifier.onKeyEvent { handleKeyEvent(it, this) }
            ) {
                navController.navigateTo(it)
            }
        }
    }

    composable(route = Destination.VOLUME_SETTINGS.route) {
        VolumeSettingsScreen(
            viewModelProvider[VolumeSettingsViewModel::class.java]
        ) { navController.navigateUp() }
    }
} …