Navigator

public abstract class Navigator<D extends NavDestination>

Known direct subclasses
ActivityNavigator

ActivityNavigator implements cross-activity navigation.

ComposeNavigator

Navigator that navigates through Composables.

DialogFragmentNavigator

Navigator that uses DialogFragment.show.

DialogNavigator

Navigator that navigates through Composables that will be hosted within a Dialog.

DynamicIncludeGraphNavigator

Navigator for include-dynamic.

FragmentNavigator

Navigator that navigates through FragmentTransaction.

NavGraphNavigator

A Navigator built specifically for NavGraph elements.

Known indirect subclasses
DynamicActivityNavigator

Dynamic feature navigator for Activity destinations.

DynamicFragmentNavigator

The Navigator that enables navigating to destinations within dynamic feature modules.

DynamicGraphNavigator

Navigator for graphs in dynamic feature modules.


Navigator defines a mechanism for navigating within an app.

Each Navigator sets the policy for a specific type of navigation, e.g. ActivityNavigator knows how to launch into destinations backed by activities using Context.startActivity.

Navigators should be able to manage their own back stack when navigating between two destinations that belong to that navigator. The NavController manages a back stack of navigators representing the current navigation stack across all navigators.

Each Navigator should add the Navigator.Name annotation to their class. Any custom attributes used by the associated destination subclass should have a name corresponding with the name of the Navigator, e.g., ActivityNavigator uses <declare-styleable name="ActivityNavigator">

Parameters
<D extends NavDestination>

the subclass of NavDestination used with this Navigator which can be used to hold any special data that will be needed to navigate to that destination. Examples include information about an intent to navigate to other activities, or a fragment class name to instantiate and swap to a new fragment.

Summary

Nested types

Navigator.Extras

Interface indicating that this class should be passed to its respective Navigator to enable Navigator specific behavior.

Navigator.Name

This annotation should be added to each Navigator subclass to denote the default name used to register the Navigator with a NavigatorProvider.

Public fields

final boolean

Whether this Navigator is actively being used by a NavController.

Public constructors

<D extends NavDestination> Navigator()

Public methods

abstract @NonNull D

Construct a new NavDestination associated with this Navigator.

void
navigate(
    @NonNull List<@NonNull NavBackStackEntry> entries,
    @Nullable NavOptions navOptions,
    @Nullable Navigator.Extras navigatorExtras
)

Navigate to a destination.

@Nullable NavDestination
navigate(
    @NonNull D destination,
    @Nullable Bundle args,
    @Nullable NavOptions navOptions,
    @Nullable Navigator.Extras navigatorExtras
)

Navigate to a destination.

@CallSuper void

Indicator that this Navigator is actively being used by a NavController.

void

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

void

Restore any state previously saved in onSaveState.

@Nullable Bundle

Called to ask for a Bundle representing the Navigator's state.

void
popBackStack(@NonNull NavBackStackEntry popUpTo, boolean savedState)

Attempt to pop this navigator's back stack, performing the appropriate navigation.

boolean

Attempt to pop this navigator's back stack, performing the appropriate navigation.

Public fields

isAttached

@NonNull
public final boolean isAttached

Whether this Navigator is actively being used by a NavController.

This is set to true when onAttach is called.

Public constructors

public final <D extends NavDestination> Navigator()
Parameters
<D extends NavDestination>

the subclass of NavDestination used with this Navigator which can be used to hold any special data that will be needed to navigate to that destination. Examples include information about an intent to navigate to other activities, or a fragment class name to instantiate and swap to a new fragment.

Public methods

createDestination

@NonNull
public abstract D createDestination()

Construct a new NavDestination associated with this Navigator.

Any initialization of the destination should be done in the destination's constructor as it is not guaranteed that every destination will be created through this method.

Returns
D

a new NavDestination

@NonNull
public void navigate(
    @NonNull List<@NonNull NavBackStackEntry> entries,
    @Nullable NavOptions navOptions,
    @Nullable Navigator.Extras navigatorExtras
)

Navigate to a destination.

Requests navigation to a given destination associated with this navigator in the navigation graph. This method generally should not be called directly; NavController will delegate to it when appropriate.

Parameters
@NonNull List<@NonNull NavBackStackEntry> entries

destination(s) to navigate to

@Nullable NavOptions navOptions

additional options for navigation

@Nullable Navigator.Extras navigatorExtras

extras unique to your Navigator.

@Nullable
public NavDestination navigate(
    @NonNull D destination,
    @Nullable Bundle args,
    @Nullable NavOptions navOptions,
    @Nullable Navigator.Extras navigatorExtras
)

Navigate to a destination.

Requests navigation to a given destination associated with this navigator in the navigation graph. This method generally should not be called directly; NavController will delegate to it when appropriate.

Parameters
@NonNull D destination

destination node to navigate to

@Nullable Bundle args

arguments to use for navigation

@Nullable NavOptions navOptions

additional options for navigation

@Nullable Navigator.Extras navigatorExtras

extras unique to your Navigator.

Returns
NavDestination

The NavDestination that should be added to the back stack or null if no change was made to the back stack (i.e., in cases of single top operations where the destination is already on top of the back stack).

onAttach

@CallSuper
@NonNull
public @CallSuper void onAttach(@NonNull NavigatorState state)

Indicator that this Navigator is actively being used by a NavController. This is called when the NavController's state is ready to be restored.

onLaunchSingleTop

@NonNull
public void onLaunchSingleTop(@NonNull NavBackStackEntry backStackEntry)

Informational callback indicating that the given backStackEntry has been affected by a NavOptions.shouldLaunchSingleTop operation. The entry provided is a new NavBackStackEntry instance with all the previous state of the old entry and possibly new arguments.

onRestoreState

@NonNull
public void onRestoreState(@NonNull Bundle savedState)

Restore any state previously saved in onSaveState. This will be called before any calls to navigate or popBackStack.

Calls to createDestination should not be dependent on any state restored here as createDestination can be called before the state is restored.

Parameters
@NonNull Bundle savedState

The state previously saved

onSaveState

@Nullable
public Bundle onSaveState()

Called to ask for a Bundle representing the Navigator's state. This will be restored in onRestoreState.

popBackStack

@NonNull
public void popBackStack(@NonNull NavBackStackEntry popUpTo, boolean savedState)

Attempt to pop this navigator's back stack, performing the appropriate navigation.

All destinations back to popUpTo should be popped off the back stack.

Parameters
@NonNull NavBackStackEntry popUpTo

the entry that should be popped off the NavigatorState.backStack along with all entries above this entry.

boolean savedState

whether any Navigator specific state associated with popUpTo should be saved to later be restored by a call to navigate with NavOptions.shouldRestoreState.

popBackStack

@NonNull
public boolean popBackStack()

Attempt to pop this navigator's back stack, performing the appropriate navigation.

Implementations should return true if navigation was successful. Implementations should return false if navigation could not be performed, for example if the navigator's back stack was empty.

Returns
boolean

true if pop was successful