我有一个登录屏幕,当登录成功并且视图模型更新可变状态变量时,我的期望是调用一个新的可组合函数来显示新屏幕,并删除登录屏幕。问题是,当Screen.AccountsScreen
显示新屏幕(又名)时,其内容不断闪烁/重绘,并且登录表单也会发生同样的情况,而该登录表单永远不会被破坏(我知道这一点是因为日志消息“Recomponing...”被无休止地打印) 。我认为发生这种情况是因为isLoginSuccessful
状态始终为真。看来我需要一个只能消耗一次的事件,这是正确的吗?如果是这样,我该怎么做?
LoginViewModel.kt
@HiltViewModel
class LoginViewModel @Inject constructor() : ViewModel() {
var isLoginSuccessful by mutableStateOf(false)
var errorMessage by mutableStateOf("")
fun onLoginClick(email: String, password:String) {
errorMessage = ""
if (credentialsValid(email, password)) {
isLoginSuccessful = true
} else {
errorMessage = "Email or password invalid"
isLoginSuccessful = false
}
}
}
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LoginScreen.kt
@Composable
fun loginScreen(
navController: NavController,
viewModel: LoginViewModel = hiltViewModel()
) {
println("Recomponing...")
// Here gos the code for the login form
if (viewModel.isLoginSuccessful) {
navController.navigate(Screen.AccountsScreen.route) { …
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