I finally started using Compose for Android and I am currently stuck at navigation. I have two questions:
1. I have implemented a bottom navigation with three buttons and one of the buttons triggeres a nested navigation graph, like:
HOME --- CONTACTS --- FAVOURITES
|
DETAILS
So when I open details screen from home and switch tabs, the behavior is correct, the state and last destination in the nested graph is memorized and when I tap again on home, it keeps the state and switches back to details. However, if I am on any of the other tabs and press back, it brings me to home but it resets the state, it doesn't bring me back into details. How can I achieve that?
Navigation Bar:
@Composable
fun BottomNavigationBar(navController: NavHostController) {
BottomNavigation {
val backStackEntry by navController.currentBackStackEntryAsState()
val currentRoute = backStackEntry?.destination?.route
BottomNavigationCollection.items.forEach { navItem ->
BottomNavigationItem(
selected = currentRoute == navItem.route,
onClick = {
navController.navigate(navItem.route) {
popUpTo(navController.graph.findStartDestination().id) {
saveState = true
}
launchSingleTop = true
restoreState = true
}
},
icon = {
Icon(
imageVector = navItem.icon,
contentDescription = navItem.title
)
},
label = {
Text(text = navItem.title)
},
)
}
}
Navigation Host:
@Composable
fun NavigationHost(navController: NavHostController) {
NavHost(
navController = navController,
startDestination = NavigationRoutes.Home.route,
route = "root"
) {
homeGraph(navController)
composable(NavigationRoutes.Contacts.route) {
ContactsScreen()
}
composable(NavigationRoutes.Favorites.route) {
FavouritesScreen()
}
}
}
Nested Home Navigation Graph:
fun NavGraphBuilder.homeGraph(navController: NavController) {
navigation(
startDestination = NavigationRoutes.Dashboard.route,
route = NavigationRoutes.Home.route
) {
composable(NavigationRoutes.Dashboard.route) {
DashboardScreen(navController)
}
composable(NavigationRoutes.Details.route) {
DetailsScreen(navController)
}
}
}
2. When I am back in home with the entire navigation stack clear and press back once more, naturally the app closes. How can I intercept back press and implement a "tap again to exit" confirmation feature at that point?
