androidandroid-jetpackandroid-jetpack-composeandroid-jetpack-navigationandroid-jetpack-compose-scaffold

Reputation: 6971

TopAppBar flashing when navigating with Compose Navigation

I have 2 screens which both have their own Scaffold and TopAppBar. When I navigate between them using the Jetpack Navigation Compose library, the app bar flashes. Why does it happen and how can I get rid of this?

Code:

Navigation:

@Composable
fun TodoNavHost(
    navController: NavHostController,
    modifier: Modifier = Modifier
) {
    NavHost(
        navController = navController,
        startDestination = TodoScreen.TodoList.name,
        modifier = modifier
    ) {
        composable(TodoScreen.TodoList.name) {
            TodoListScreen(
                onTodoEditClicked = { todo ->
                    navController.navigate("${TodoScreen.AddEditTodo.name}?todoId=${todo.id}")
                },
                onFabAddNewTodoClicked = {
                    navController.navigate(TodoScreen.AddEditTodo.name)
                }
            )
        }
        composable(
            "${TodoScreen.AddEditTodo.name}?todoId={todoId}", 
            arguments = listOf(
                navArgument("todoId") {
                    type = NavType.LongType
                    defaultValue = -1L
                }
            )
        ) {
            AddEditTodoScreen(
                onNavigateUp = {
                    navController.popBackStack() 
                },
                onNavigateBackWithResult = { result ->
                    navController.navigate(TodoScreen.TodoList.name)
                }
            )
        }
    }
}

Todo list screen Scaffold with TopAppBar:

@Composable
fun TodoListBody(
    todos: List<Todo>,
    todoExpandedStates: Map<Long, Boolean>,
    onTodoItemClicked: (Todo) -> Unit,
    onTodoCheckedChanged: (Todo, Boolean) -> Unit,
    onTodoEditClicked: (Todo) -> Unit,
    onFabAddNewTodoClicked: () -> Unit,
    onDeleteAllCompletedConfirmed: () -> Unit,
    modifier: Modifier = Modifier,
    errorSnackbarMessage: String = "",
    errorSnackbarShown: Boolean = false
) {

    var menuExpanded by remember { mutableStateOf(false) }
    var showDeleteAllCompletedConfirmationDialog by rememberSaveable { mutableStateOf(false) }

    Scaffold(
        modifier,
        topBar = {
            TopAppBar(
                title = { Text("My Todos") },
                actions = {
                    IconButton(
                        onClick = { menuExpanded = !menuExpanded },
                        modifier = Modifier.semantics {
                            contentDescription = "Options Menu"
                        }
                    ) {
                        Icon(Icons.Default.MoreVert, contentDescription = "Show menu")
                    }
                    DropdownMenu(
                        expanded = menuExpanded,
                        onDismissRequest = { menuExpanded = false }) {
                        DropdownMenuItem(
                            onClick = {
                                showDeleteAllCompletedConfirmationDialog = true
                                menuExpanded = false
                            },
                            modifier = Modifier.semantics {
                                contentDescription = "Option Delete All Completed"
                            }) {
                            Text("Delete all completed")
                        }
                    }
                }

            )
        },
[...]

Add/edit screen Scaffold with TopAppBar:

@Composable
fun AddEditTodoBody(
    todo: Todo?,
    todoTitle: String,
    setTitle: (String) -> Unit,
    todoImportance: Boolean,
    setImportance: (Boolean) -> Unit,
    onSaveClick: () -> Unit,
    onNavigateUp: () -> Unit,
    modifier: Modifier = Modifier
) {
    Scaffold(
        modifier,
        topBar = {
            TopAppBar(
                title = { Text(todo?.let { "Edit Todo" } ?: "Add Todo") },
                actions = {
                    IconButton(onClick = onSaveClick) {
                        Icon(Icons.Default.Save, contentDescription = "Save Todo")
                    }
                },
                navigationIcon = {
                    IconButton(onClick = onNavigateUp) {
                        Icon(Icons.Default.ArrowBack, contentDescription = "Back")
                    }
                }
            )
        },
    ) { innerPadding ->
        BodyContent(
            todoTitle = todoTitle,
            setTitle = setTitle,
            todoImportance = todoImportance,
            setImportance = setImportance,
            modifier = Modifier.padding(innerPadding)
        )
    }
}

Upvotes: 19

Answers (10)

Ayushi Khandelwal

Reputation: 336

Updating to version 2.8.0-alpha06 solved this issue for me

Upvotes: 0

alexspurlock25

Reputation: 135

Without adding another package, as of Dec/2023, you can remove the default animation like so

NavHost(
    navController = navController,
    startDestination = HOME_ROUTE,
    route = ROOT_ROUTE,
    enterTransition = {
        EnterTransition.None // removes the blinking/fade effect
    },
    exitTransition = {
        ExitTransition.None // remove the blinking/fade effect
    }
) {
    // composables
}

Put this in your root nav host. Here is the version that I am using(as of Dec/2/2023

implementation("androidx.navigation:navigation-compose:2.7.5")

Upvotes: 0

Rickard Elimää

Reputation: 7591

The problem is that the view in the NavHost has a default crossfade animation. You must override it to stop the flashing, as the example below shows with noEnterTransition and noExistTransition for MainScreen.

class MainActivity : ComponentActivity() {
    private val noEnterTransition: AnimatedContentTransitionScope<NavBackStackEntry>.() -> EnterTransition =
        {
            fadeIn(
                animationSpec = tween(durationMillis = 200),
                initialAlpha = 0.99f
            )
        }

    private val noExitTransition: AnimatedContentTransitionScope<NavBackStackEntry>.() -> ExitTransition =
        {
            fadeOut(
                animationSpec = tween(durationMillis = 300),
                targetAlpha = 0.99f
            )
        }

    /.../

    override fun onCreate(savedInstanceState: Bundle?) {
        setContent {
            val navController = rememberNavController()
            YourTheme() {

                Surface(color = MaterialTheme.colorScheme.background) {
                    NavHost(navController = navController, startDestination = "main") {
                        composable(
                            route = "main",
                            popEnterTransition = noEnterTransition,
                            exitTransition = noExitTransition,
                            popExitTransition = noExitTransition
                        ) {
                            // MainScreen(navController = navController)
                        }

                        composable(
                            route = "detail",
                            enterTransition = {
                                slideIntoContainer(
                                    towards = AnimatedContentTransitionScope.SlideDirection.Companion.Left,
                                    animationSpec = tween(200, easing = EaseOut)
                                )
                            },
                            popExitTransition = {
                                slideOutOfContainer(
                                    towards = AnimatedContentTransitionScope.SlideDirection.Companion.Right,
                                    animationSpec = tween(150, easing = EaseOut)
                                )
                            },
                        ) {
                            // DetailScreen(navController = navController)
                        }
                    }
                }
            }
        }
    }
}

Upvotes: 1

Simone

Reputation: 1548

In order not to blink (or to slide if you have AnimatedNavHost) you should put the TopAppBar in the activity and outside the NavHost, otherwise the TopAppBar is just part of the screen and makes transitions like every other screen element:

// Activity with your navigation host
setContent {
    MyAppTheme {
        Scaffold(
            topBar = { TopAppBar(...) }
        ) { padding ->
            TodoNavHost(padding, ...) { }
        }
    }
}

From the Scaffold containing the TopAppBar comes the padding parameter, that you should pass to the NavHost and use it in the screen like you have done in your example

Upvotes: 1

rafakob

Reputation: 4346

I think I found an easy solution for that issue (works on Compose version 1.4.0).

My setup - blinking

All of my screens have their own toolbar wrapped in the scaffold:

// Some Composable screnn

Scaffold(
    topBar = { TopAppBar(...) }
) {
    ScreenContent()
}

Main activity which holds the nav host is defined like that:

// Activity with NavHost

setContent {
    AppTheme {
        NavHost(...) { }
    }
}

Solution - no blinking!

Wrap you NavHost in activity in a Surface:

setContent {
    AppTheme {
        Surface {
            NavHost(...) { }
        }
    }
}

Rest of the screens stay the same. No blinking and transition animation between destinations is almost the same like it was with fragments (subtle fade in/fade out). So far I haven't found any negative side effects of that.

Upvotes: 8

CryptoCode

Reputation: 1117

Alternative to removing Animation you can change animations for example:

@Composable
private fun ScreenContent() {
    val navController = rememberAnimatedNavController()
    val springSpec = spring<IntOffset>(dampingRatio = Spring.DampingRatioMediumBouncy)
    val tweenSpec = tween<IntOffset>(durationMillis = 2000, easing = CubicBezierEasing(0.08f, 0.93f, 0.68f, 1.27f))
    ...
    ) { innerPadding ->
        AnimatedNavHost(
            navController = navController,
            startDestination = BottomNavDestinations.TimerScreen.route,
            enterTransition = { slideInHorizontally(initialOffsetX = { 1000 }, animationSpec = springSpec) },
            exitTransition = { slideOutHorizontally(targetOffsetX = { -1000 }, animationSpec = springSpec) },
            popEnterTransition = { slideInHorizontally(initialOffsetX = { 1000 }, animationSpec = tweenSpec) },
            popExitTransition = { slideOutHorizontally(targetOffsetX = { -1000 }, animationSpec = tweenSpec) },
            modifier = Modifier.padding(innerPadding)
    ) {}

Upvotes: 0

CryptoCode

Reputation: 1117

With the newer library implementation "com.google.accompanist:accompanist-navigation-animation:0.24.1-alpha" you need to have the AnimatedNavHost like this

AnimatedNavHost(
            navController = navController,
            startDestination = BottomNavDestinations.TimerScreen.route,
            enterTransition = { EnterTransition.None },
            exitTransition = { ExitTransition.None },
            popEnterTransition = { EnterTransition.None },
            popExitTransition = { ExitTransition.None },
            modifier = Modifier.padding(innerPadding)

Also

Replace rememberNavController() with rememberAnimatedNavController()

Replace NavHost with AnimatedNavHost

Replace import androidx.navigation.compose.navigation with import com.google.accompanist.navigation.animation.navigation

Replace import androidx.navigation.compose.composable with import com.google.accompanist.navigation.animation.composable

Upvotes: 1

Florian Walther

Reputation: 6971

The flashing is caused by the default cross-fade animation in more recent versions of the navigation-compose library. The only way to get rid of it right now (without downgrading the dependency) is by using the Accompanist animation library:

implementation "com.google.accompanist:accompanist-navigation-animation:0.20.0"

And then replace the normal NavHost with Accompanist's AnimatedNavHost, replace rememberNavController() with rememberAnimatedNavController() and disable the transitions animations:

AnimatedNavHost(
        navController = navController,
        startDestination = bottomNavDestinations[0].fullRoute,
        enterTransition = { _, _ -> EnterTransition.None },
        exitTransition = { _, _ -> ExitTransition.None },
        popEnterTransition = { _, _ -> EnterTransition.None },
        popExitTransition = { _, _ -> ExitTransition.None },
        modifier = modifier,
    ) {
        [...}
    }

Upvotes: 8

Artur Popławski

Reputation: 111

I got the same issue having a "scaffold-per-screen" architecture. What helped, to my surprise, was lowering androidx.navigation:navigation-compose version to 2.4.0-alpha04.

Upvotes: 1

Richard Onslow Roper

Reputation: 6835

It is the expected behaviour. You are constructing two separate app bars for both the screens so they are bound to flash. This is not the correct way. The correct way would be to actually put the scaffold in your main activity and place the NavHost as it's content. If you wish to modify the app bar, create variables to hold state. Then modify them from the Composables. Ideally, store then in a viewmodel. That is how it is done in compose. Through variables.

Thanks

Upvotes: -1

TopAppBar flashing when navigating with Compose Navigation

Answers (10)

My setup - blinking

Solution - no blinking!

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