NavigatorState

public abstract class NavigatorState

Known direct subclasses
TestNavigatorState

An implementation of NavigatorState that allows testing a androidx.navigation.Navigator in isolation (i.e., without requiring a androidx.navigation.NavController).


The NavigatorState encapsulates the state shared between the Navigator and the NavController.

Summary

Public fields

final @NonNull StateFlow<@NonNull List<@NonNull NavBackStackEntry>>

While the NavController is responsible for the combined back stack across all Navigators, this back stack is specifically the set of destinations associated with this Navigator.

final @NonNull StateFlow<@NonNull List<@NonNull NavBackStackEntry>>

This is the set of currently running transitions.

Public constructors

Public methods

abstract @NonNull NavBackStackEntry
createBackStackEntry(
    @NonNull NavDestination destination,
    @Nullable Bundle arguments
)

Create a new NavBackStackEntry from a given destination and arguments.

void

This removes the given NavBackStackEntry from the set of the transitions in progress.

@CallSuper void

Informational callback indicating that the given backStackEntry has been affected by a NavOptions.shouldLaunchSingleTop operation.

void
pop(@NonNull NavBackStackEntry popUpTo, boolean saveState)

Pop all destinations up to and including popUpTo.

void
popWithTransition(@NonNull NavBackStackEntry popUpTo, boolean saveState)

Pops all destinations up to and including popUpTo.

void
push(@NonNull NavBackStackEntry backStackEntry)

Adds the given backStackEntry to the backStack.

void

Adds the given backStackEntry to the backStack.

Public fields

backStack

@NonNull
public final @NonNull StateFlow<@NonNull List<@NonNull NavBackStackEntry>> backStack

While the NavController is responsible for the combined back stack across all Navigators, this back stack is specifically the set of destinations associated with this Navigator.

Changing the back stack must be done via push and pop.

transitionsInProgress

@NonNull
public final @NonNull StateFlow<@NonNull List<@NonNull NavBackStackEntry>> transitionsInProgress

This is the set of currently running transitions. Use this set to retrieve the entry and call markTransitionComplete once the transition is complete.

Public constructors

public final NavigatorState()

Public methods

createBackStackEntry

@NonNull
public abstract NavBackStackEntry createBackStackEntry(
    @NonNull NavDestination destination,
    @Nullable Bundle arguments
)

Create a new NavBackStackEntry from a given destination and arguments.

markTransitionComplete

@NonNull
public void markTransitionComplete(@NonNull NavBackStackEntry entry)

This removes the given NavBackStackEntry from the set of the transitions in progress. This should be called in conjunction with pushWithTransition and popWithTransition as those call are responsible for adding entries to transitionsInProgress.

Failing to call this method could result in entries being prevented from reaching their final Lifecycle.State}.

onLaunchSingleTop

@CallSuper
@NonNull
public @CallSuper void onLaunchSingleTop(@NonNull NavBackStackEntry backStackEntry)

Informational callback indicating that the given backStackEntry has been affected by a NavOptions.shouldLaunchSingleTop operation.

pop

@NonNull
public void pop(@NonNull NavBackStackEntry popUpTo, boolean saveState)

Pop all destinations up to and including popUpTo. This will remove those destinations from the backStack, saving their state if saveState is true.

popWithTransition

@NonNull
public void popWithTransition(@NonNull NavBackStackEntry popUpTo, boolean saveState)

Pops all destinations up to and including popUpTo. This also adds the given and incoming entry to the set of in progress transitions. Added entries have their Lifecycle held at Lifecycle.State.CREATED until an entry is passed into the markTransitionComplete callback, when they are allowed to go to Lifecycle.State.DESTROYED and have their state cleared.

This will remove those destinations from the backStack, saving their state if saveState is true.

push

@NonNull
public void push(@NonNull NavBackStackEntry backStackEntry)

Adds the given backStackEntry to the backStack.

pushWithTransition

@NonNull
public void pushWithTransition(@NonNull NavBackStackEntry backStackEntry)

Adds the given backStackEntry to the backStack. This also adds the given and previous entry to the set of in progress transitions. Added entries have their Lifecycle capped at Lifecycle.State.STARTED until an entry is passed into the markTransitionComplete callback, when they are allowed to go to Lifecycle.State.RESUMED.