Navigate from top app bar

This guide demonstrates how you can make the navigation icon in a top app bar perform navigation actions.

Example

The following snippet is a minimal example of how you can implement a top app bar with a functional navigation icon. In this case, the icon takes the user to their previous destination in the app:

@Composable fun TopBarNavigationExample(  navigateBack: () -> Unit, ) {  Scaffold(  topBar = {  CenterAlignedTopAppBar(  title = {  Text(  "Navigation example",  )  },  navigationIcon = {  IconButton(onClick = navigateBack) {  Icon(  imageVector = Icons.AutoMirrored.Filled.ArrowBack,  contentDescription = "Localized description"  )  }  },  )  },  ) { innerPadding ->  Text(  "Click the back button to pop from the back stack.",  modifier = Modifier.padding(innerPadding),  )  } }
AppBar.kt

Key points about the code

Note the following in this example:

  • The composable TopBarNavigationExample defines a parameter navigateBack of type () -> Unit.
  • It passes navigateBack for the navigationIcon parameter of CenterAlignedTopAppBar.

As such, whenever the user clicks the navigation icon in the top app back, it calls navigateBack().

Pass a function

This example uses a back arrow for the icon. As such, the argument for navigateBack() should take the user to the previous destination.

To do so, pass TopBarNavigationExample a call to NavController.popBackStack(). You do this where you build your navigation graph. For example:

NavHost(navController, startDestination = "home") {  composable("topBarNavigationExample") {  TopBarNavigationExample{ navController.popBackStack() }  }  // Other destinations...

Additional resources

For more information on how to implement navigation in your app, see the following series of guides: