我试图理解如何使用ViewModel，它保存可以传递到不同屏幕的值。
我写了一个非常简单的程序来尝试理解这个概念。
以下是我的主要活动：

sealed class Destination(val route: String) {
    object PlayerSelection: Destination("PlayerSelection")
    object TwoPlayerGame: Destination("TwoPlayerGame")
    object ThreePlayerGame: Destination("ThreePlayerGame")
    object FourPlayerGame: Destination("FourPlayerGame")
}
class MainActivity : ComponentActivity() {
    private val viewModel: MainViewModel by viewModels()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Viewmodels_and_NavigationTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    ScreenSetup(viewModel)
                }
            }
        }
    }
}

字符串
下面是我的NavigationAppHost：

@Composable
fun NavigationAppHost (navController: NavController, viewModel: MainViewModel) {
    NavHost(navController = navController as NavHostController, startDestination = "PlayerSelection") {
        composable(Destination.PlayerSelection.route)  { PlayerSelection(navController,MainViewModel()) }
        composable(Destination.TwoPlayerGame.route) {TwoPlayerGame(navController,MainViewModel())}
        composable(Destination.ThreePlayerGame.route) {ThreePlayerGame(navController,MainViewModel())}
        composable(Destination.FourPlayerGame.route) {FourPlayerGame(navController,MainViewModel())}
    }
}

型
下面是我的ScreenSetup：

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun ScreenSetup(viewModel: MainViewModel) {
//Navigation Stuff
    val navController = rememberNavController()
    Scaffold(
        topBar = { TopAppBar(title = {  Text(text = "Viewmodels and Navigation") }) },
        content = { padding ->
            Column(Modifier.padding(padding)) {
                NavigationAppHost(navController = navController,viewModel)
            }
        },
        bottomBar = { Text(text = "BottomBar") }
    )
}

型
以下是Composable PlayerSelection：

@Composable
fun PlayerSelection(navController: NavController, viewModel: MainViewModel) {
    val HowManyPlayers: Int by viewModel.howManyPlayers.collectAsState()
    Column {
        Row {
            Text(text = "How Many Players?")
        }
        Row() {
            Button(onClick = { viewModel.Selection(2) }) {
                Text("Two Players")
            }
            Button(onClick = { viewModel.Selection(3) }) {
                Text("Three Players")
            }
            Button(onClick = { viewModel.Selection(4) }) {
                Text("Four Players")
            }
            
              }
        Row() {
            Text(text = "Current Value Held in MainViewModel = ${HowManyPlayers}")
        }
        Button(onClick = {
            if (HowManyPlayers == 2) {
                navController.navigate(Destination.TwoPlayerGame.route)
                      }
            if (HowManyPlayers == 3) {
                navController.navigate(Destination.ThreePlayerGame.route)
            }
            if (HowManyPlayers == 4) {
                navController.navigate(Destination.FourPlayerGame.route)
            }
        }) {
            Text(text = "Click To Navigate To Next Screen")
        }
    }
}

型
下面是MainViewModel：

class MainViewModel : ViewModel() {
    var _howManyPlayers = MutableStateFlow(0)
    var howManyPlayers = _howManyPlayers.asStateFlow()
    fun Selection(players:Int) {
    _howManyPlayers.value = players
    
    }
}

型
下面是TwoPlayerGame Composable：

@Composable
fun TwoPlayerGame(navController: NavController, viewModel: MainViewModel) {
    val howManyPlayers by viewModel.howManyPlayers.collectAsState()
    Column {
        Row(Modifier.padding(50.dp)) {
            Text(text = "Two Player Game")
        }
        Row {
            Text(text = "Value of howManyPlayers in viewmodel = ${howManyPlayers}")
        }
    }
}

型
当用户在PlayerSelection屏幕中选择多少个玩家时，MainViewModel中的HowManyPlayers变量会根据用户按下的按钮成功更改。我可以看到这一行的工作情况：
第一个月
这很酷。然而，当我点击按钮导航到TwoPlayerGame时，MainViewModel中的变量HowManyPlayers再次重置为0。为什么在导航到新屏幕时，MainViewModel中的HowManyPlayers值重置为0？是否有一种方法可以将ViewModel传递到不同的屏幕，同时保留传递的ViewModel中的变量值？
谢谢你考虑我的问题，我真的很感激！