docs : navigation, 화면전환, navBackStackEntry (#3)

[philipy355]

class MainActivity : ComponentActivity() {
    @OptIn(ExperimentalMaterial3Api::class, ExperimentalComposeUiApi::class)
    @SuppressLint("UnusedMaterial3ScaffoldPaddingParameter",
        "UnusedMaterialScaffoldPaddingParameter"
    )
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            val navController = rememberNavController()

            NavHost(navController = navController, startDestination = "first",){
                composable("first"){
                    FirstScreen(navController)
                }
                composable("second"){
                    SecondScreen(navController)
                }
                composable("third/{value}"){
                    navBackStackEntry ->
                    ThirdScreen(
                        navController = navController,
                        value = navBackStackEntry.arguments?.getString("value") ?: "")
                }
            }
        }
    }
}

• Composable FirstScreen, SecondScrenn, ThirdScreen

  
  @OptIn(ExperimentalMaterial3Api::class)
  @Composable
  fun FirstScreen(navController: NavController){
  val (value, setValue) = remember {
      mutableStateOf("")
  }
  Column(
      modifier = Modifier.fillMaxSize(),
      verticalArrangement = Arrangement.Center,
      horizontalAlignment = Alignment.CenterHorizontally,
  ){
      Text(text = "첫 화면")
      Spacer(modifier = Modifier.height(16.dp))
      Button(onClick = {
          navController.navigate("second")
      }){
          Text("두 번째!")
      }
      Spacer(modifier = Modifier.height(16.dp))
      TextField(value = value, onValueChange = setValue)
      Button(onClick = {
          if (value.isNotEmpty()){
              navController.navigate("third/$value")
          }
      }){
          Text("세 번째!")
      }
  }
  }

@Composable fun SecondScreen(navController: NavController){ Column( modifier = Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally, ){ Text(text = "두번째 화면") Spacer(modifier = Modifier.height(16.dp)) Button(onClick = { //navController.navigate("first") navController.navigateUp() //navController.popBackStack() }){ Text("뒤로가기!") } } }

@Composable fun ThirdScreen(navController: NavController, value: String){ Column( modifier = Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally, ){ Text(text = "세번째 화면") Spacer(modifier = Modifier.height(16.dp)) Text(value) Button(onClick = { navController.navigateUp() }){ Text("뒤로가기") } } }

- 의존성
```xml
    //Navigation
    implementation "androidx.navigation:navigation-compose:2.4.0-alpha10"

[philipy355]

참고 url https://mvnrepository.com/artifact/androidx.navigation/navigation-compose/2.4.0