kotlin - 调用只能在使用 Compose Navigation 的 @composable 函数的上下文中发生

Question

您好，由于@composable 调用只能在@composable 函数的上下文中发生，我目前正在努力在Jetpack Compose 中进行导航。我有一个功能:

private fun signInResult(result: FirebaseAuthUIAuthenticationResult) {
        val response = result.idpResponse
        if (result.resultCode == RESULT_OK) {
            user = FirebaseAuth.getInstance().currentUser
            Log.e("MainActivity.kt", "Innlogging vellykket")
            ScreenMain()
        } else {
            Log.e("MainActivity.kt", "Feil med innlogging" + response?.error?.errorCode)
        }
    }

与下面显示的导航类一起使用时，我只收到上面显示的错误消息，我该如何解决？

@Composable
         fun ScreenMain(){
    val navController = rememberNavController()

    NavHost(navController = navController, startDestination = Routes.Vareliste.route) {

        composable(Routes.SignUp.route) {
            SignUp(navController = navController)
        }

        composable(Routes.ForgotPassword.route) { navBackStack ->
            ForgotPassword(navController = navController)
        }

        composable(Routes.Vareliste.route) { navBackStack ->
           Vareliste(navController = navController)
       }

       composable(Routes.Handlekurv.route) { navBackStack ->
            Handlekurv(navController = navController)
        }
        
        composable(Routes.Profileromoss.route) { navBackStack ->
            Profileromoss(navController = navController)
        }

   }
}

编辑完整代码如果你们想看的话，这里是类(class)的完整代码!

class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContent {
        JetpackComposeDemoTheme {
             Surface(
                     modifier = Modifier.fillMaxSize(),
                      color = MaterialTheme.colors.background
                            ) {
                LoginPage()
            }
        }
    }
}

private var user: FirebaseUser? = FirebaseAuth.getInstance().currentUser
private lateinit var auth: FirebaseAuth



@Composable
fun LoginPage() {
    Box(modifier = Modifier.fillMaxSize()) {
    }
    Column(
        modifier = Modifier.padding(20.dp),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally
    ) {

        Text(text = "Velkommen til ITGuys", style = TextStyle(fontSize = 36.sp))

        Spacer(modifier = Modifier.height(20.dp))
        Box(modifier = Modifier.padding(40.dp, 0.dp, 40.dp, 0.dp)) {
            Button(
                onClick = { signIn() },
                shape = RoundedCornerShape(50.dp),
                modifier = Modifier
                    .fillMaxWidth()
                    .height(50.dp)
            ) {
                Text(text = "Logg inn")
            }
        }
    }
}

private fun signIn() {
    val providers = arrayListOf(
        AuthUI.IdpConfig.EmailBuilder().build(),
        AuthUI.IdpConfig.GoogleBuilder().build()
    )
    val signinIntent = AuthUI.getInstance()
    .createSignInIntentBuilder()
    .setAvailableProviders(providers)
    .build()

    signInLauncher.launch(signinIntent)
}



private val signInLauncher = registerForActivityResult(
    FirebaseAuthUIActivityResultContract()
) {
    res -> this.signInResult(res)
}

private fun signInResult(result: FirebaseAuthUIAuthenticationResult) {
    val response = result.idpResponse
    if (result.resultCode == RESULT_OK) {
        user = FirebaseAuth.getInstance().currentUser
        Log.e("MainActivity.kt", "Innlogging vellykket")
        ScreenMain()
    } else {
        Log.e("MainActivity.kt", "Feil med innlogging" + response?.error?.errorCode)
    }
}

我需要添加更多文本才能发布这么多代码，您可以忽略此文本，因为它只是为了能够发布。

Answer 1

如@z.y 所述，您可以传递带有 onFirebaseAuthSuccess 的 lambda。我还要补充一点，当您将 navController 传递到注册屏幕时，您需要传递的 lambda 回调应该类似于

onFirebaseAuthSuccess = { navController.navigate(Routes.Profileromoss.route) } - or whatever route you need

基于

composable(Routes.SignUp.route) {
            SignUp(navController = navController)
        }

我假设您的 signIn 屏幕是从可组合项的范围内调用的。如果您可以添加包含您如何调用 signInResult 函数的代码摘录，我们就可以确定这一点。