trying to save value of my edit text field after changing to one activity to 2nd activity and then return to 1st activity in jetpack compose

Issue

1. I am trying to save my edit text value after changing from one activity to another
2. ex: just like in a register pager (first you have to fill all data in pages and in the end submit.
3. I am having trouble here is if i want to edit my first page data so i moved from 2nd page to 1st page but my 1st page doesn't show any data
4. I tried using save state and restore state of navigation but it wont help

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent { ScreenNavigation() }
    }
}

@Composable
fun Page1(navController: NavHostController) {
    var test = remember { mutableStateOf("") }

    Column() {
        TextField(value = test.value, onValueChange = { test.value = it })
        Button(
            onClick = {
                navController.navigate(ScreenRoute.Page2.name) {
                    popUpTo(ScreenRoute.Page2.name) { saveState = true }
                    launchSingleTop = true

                    restoreState = true
                }
            }
        ) {}

        Text(text = "Page1")
        TextField(
            value = test.value,
            onValueChange = { test.value = it },
        )
    }
}

@Composable
fun Page2(navController: NavHostController) {
    var test = remember { mutableStateOf("") }

    Column() {
        TextField(value = test.value, onValueChange = { test.value = it })
        Button(
            onClick = {
                navController.navigate(ScreenRoute.Page1.name) {
                    popUpTo(ScreenRoute.Page1.name) { saveState = true }
                    launchSingleTop = true

                    restoreState = true
                }
            }
        ) {}
        Text(text = "Page2")
    }
}

// code for navigation

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

    NavHost(navController = navController, startDestination = ScreenRoute.Page1.name) {
        composable(ScreenRoute.Page1.name) { Page1(navController) }

        composable(ScreenRoute.Page2.name) { Page2(navController) }
    }
}

// code for screen route
enum class ScreenRoute {
    Page1,
    Page2,
}

Solution

Have both variables outside the functions and above class like this:

var test1 = mutableStateOf("")
var test2 = mutableStateOf("") 

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent { ScreenNavigation() }
    }
}

@Composable
fun Page1(navController: NavHostController) {
    

    Column() {
        TextField(value = test1.value, onValueChange = { test1.value = it })
        Button(
            onClick = {
                navController.navigate(ScreenRoute.Page2.name) {
                    popUpTo(ScreenRoute.Page2.name) { saveState = true }
                    launchSingleTop = true

                    restoreState = true
                }
            }
        ) {}

        Text(text = "Page1")
        TextField(
            value = test1.value,
            onValueChange = { test1.value = it },
        )
    }
}

@Composable
fun Page2(navController: NavHostController) {


    Column() {
        TextField(value = test2.value, onValueChange = { test2.value = it })
        Button(
            onClick = {
                navController.navigate(ScreenRoute.Page1.name) {
                    popUpTo(ScreenRoute.Page1.name) { saveState = true }
                    launchSingleTop = true

                    restoreState = true
                }
            }
        ) {}
        Text(text = "Page2")
    }
}

// code for navigation

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

    NavHost(navController = navController, startDestination =       ScreenRoute.Page1.name) {
        composable(ScreenRoute.Page1.name) { Page1(navController) }

        composable(ScreenRoute.Page2.name) { Page2(navController) }
    }
}

// code for screen route
enum class ScreenRoute {
    Page1,
    Page2,
}

Answered By - Aman Kaushik