我的ViewModel被重新组成，以更改mutableState值

发布于 2025-01-29 20:05:15 字数 1486 浏览 5 评论 0 原文

loginscreen（）是我的可组合函数，我正在尝试使用其中的文本字段，该文本字段从我的ViewModel中获取电子邮件数据。每个时间我的电子邮件值都会更改，登录屏幕函数已重新计算并重新引入我的ViewModel，从而导致我的TextField不会更改。我想知道为什么会发生这种情况以及如何解决。

@Composable
fun LoginScreen(navController: NavHostController
){

    var viewModel=LoginScreenViewModel(navController = navController, LocalContext.current)

    Column(
        modifier = Modifier
            .fillMaxSize()
            .background(primary)
            .verticalScroll(rememberScrollState())
    ){
        TextField(value = viewModel.emailText
            , onValueChange = {
                viewModel.emailText=it
                Log.i("Email text",viewModel.emailText)
            },
            placeholder = {
                Text("Email")
            },
            keyboardOptions = KeyboardOptions(
                keyboardType = KeyboardType.Email
            ),
            modifier = Modifier
                .fillMaxWidth()
                .padding(top = 10.dp)
        )
    }
}

class LoginScreenViewModel():ViewModel() {
    var emailText by mutableStateOf("a")
    var passwordText by mutableStateOf("")
    var isVisibilityOn by mutableStateOf(false)

    lateinit var mAuth:FirebaseAuth

    private lateinit var navController: NavHostController
    private lateinit var context: Context

    constructor(navController: NavHostController,context:Context) : this() {
        this.navController=navController
        this.context=context
    }
}

原文

LoginScreen() is my composable function and i am trying to use a textfield inside it which takes email data from my viewmodel.Everytime my email values changes, LoginScreen function is recomposed and reinitialises my viewModel which results in no change in my textfield.
I am wondering why is this happening and how to fix it.

@Composable
fun LoginScreen(navController: NavHostController
){

    var viewModel=LoginScreenViewModel(navController = navController, LocalContext.current)

    Column(
        modifier = Modifier
            .fillMaxSize()
            .background(primary)
            .verticalScroll(rememberScrollState())
    ){
        TextField(value = viewModel.emailText
            , onValueChange = {
                viewModel.emailText=it
                Log.i("Email text",viewModel.emailText)
            },
            placeholder = {
                Text("Email")
            },
            keyboardOptions = KeyboardOptions(
                keyboardType = KeyboardType.Email
            ),
            modifier = Modifier
                .fillMaxWidth()
                .padding(top = 10.dp)
        )
    }
}

class LoginScreenViewModel():ViewModel() {
    var emailText by mutableStateOf("a")
    var passwordText by mutableStateOf("")
    var isVisibilityOn by mutableStateOf(false)

    lateinit var mAuth:FirebaseAuth

    private lateinit var navController: NavHostController
    private lateinit var context: Context

    constructor(navController: NavHostController,context:Context) : this() {
        this.navController=navController
        this.context=context
    }
}

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可爱咩 2025-02-05 20:05:15

var viewModel = loginscreenviewmodel（navcontroller = navcontroller，localcontext.current）

，因为您不使用 val viewModel =记住{viewmodelprovider（localviewModelStore.current.current，object，object object object：viewModelProvider.factory.factory; clazz：class＆lt; t＆gt;）= loginScreenViewModel（navController）}}）。get（loginscreenviewmodel :: class.java）} 以获取对您的ViewModel的引用。

尽管您可以用只是调用 = view> = viewModel（factory =/ * factory * factory */）。

然后，您不能直接将 navController 引用到 viewModel ，您需要使用频道和可置效果/启动效应来发送命令从ViewModel到NavController。