NavHostFragment

Kotlin |Java

open class NavHostFragment : Fragment, NavHost

kotlin.Any
↳	androidx.fragment.app.Fragment
	↳	androidx.navigation.fragment.NavHostFragment

Known Direct Subclasses DynamicNavHostFragment DynamicNavHostFragment The NavHostFragment for dynamic features.

NavHostFragment provides an area within your layout for self-contained navigation to occur.

NavHostFragment is intended to be used as the content area within a layout resource defining your app's chrome around it, e.g.:

<androidx.drawerlayout.widget.DrawerLayout
         xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
     <fragment
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:id="@+id/my_nav_host_fragment"
             android:name="androidx.navigation.fragment.NavHostFragment"
             app:navGraph="@navigation/nav_sample"
             app:defaultNavHost="true" />
     <android.support.design.widget.NavigationView
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
             android:layout_gravity="start"/>
  </androidx.drawerlayout.widget.DrawerLayout>
  

Each NavHostFragment has a NavController that defines valid navigation within the navigation host. This includes the navigation graph as well as navigation state such as current location and back stack that will be saved and restored along with the NavHostFragment itself.

NavHostFragments register their navigation controller at the root of their view subtree such that any descendant can obtain the controller instance through the Navigation helper class's methods such as Navigation#findNavController(View). View event listener implementations such as android.view.View.OnClickListener within navigation destination fragments can use these helpers to navigate based on user interaction without creating a tight coupling to the navigation host.

Summary

Public constructors
<init>() NavHostFragment provides an area within your layout for self-contained navigation to occur.

Public methods
open static NavHostFragment	create(@NavigationRes graphResId: Int) Create a new NavHostFragment instance with an inflated NavGraph resource.
open static NavHostFragment	create(@NavigationRes graphResId: Int, @Nullable startDestinationArgs: Bundle?) Create a new NavHostFragment instance with an inflated NavGraph resource.
open static NavController	findNavController(@NonNull fragment: Fragment) Find a NavController given a local Fragment.
NavController	getNavController() Returns the navigation controller for this navigation host.
open Unit	onAttach(@NonNull context: Context)
open Unit	onAttachFragment(@NonNull childFragment: Fragment)
open Unit	onCreate(@Nullable savedInstanceState: Bundle?)
open View?	onCreateView(@NonNull inflater: LayoutInflater, @Nullable container: ViewGroup?, @Nullable savedInstanceState: Bundle?)
open Unit	onDestroyView()
open Unit	onInflate(@NonNull context: Context, @NonNull attrs: AttributeSet, @Nullable savedInstanceState: Bundle?)
open Unit	onPrimaryNavigationFragmentChanged(isPrimaryNavigationFragment: Boolean)
open Unit	onSaveInstanceState(@NonNull outState: Bundle)
open Unit	onViewCreated(@NonNull view: View, @Nullable savedInstanceState: Bundle?)

Protected methods
open Navigator<out FragmentNavigator.Destination!>	createFragmentNavigator() Create the FragmentNavigator that this NavHostFragment will use.
open Unit	onCreateNavController(@NonNull navController: NavController) Callback for when the NavController is created.

Inherited functions

From class Fragment Unit dump(@NonNull prefix: String, @Nullable fd: FileDescriptor?, @NonNull writer: PrintWriter, @Nullable args: Array<String!>?) Print the Fragments's state into the given stream. Boolean equals(@Nullable other: Any?) Subclasses can not override equals(). FragmentActivity? getActivity() Return the FragmentActivity this fragment is currently associated with. May return null if the fragment is associated with a Context instead. Boolean getAllowEnterTransitionOverlap() Returns whether the the exit transition and enter transition overlap or not. When true, the enter transition will start as soon as possible. When false, the enter transition will wait until the exit transition completes before starting. Boolean getAllowReturnTransitionOverlap() Returns whether the the return transition and reenter transition overlap or not. When true, the reenter transition will start as soon as possible. When false, the reenter transition will wait until the return transition completes before starting. Bundle? getArguments() Return the arguments supplied when the fragment was instantiated, if any. FragmentManager getChildFragmentManager() Return a private FragmentManager for placing and managing Fragments inside of this Fragment. Context? getContext() Return the Context this fragment is currently associated with. ViewModelProvider.Factory getDefaultViewModelProviderFactory() Returns the default ViewModelProvider.Factory that should be used when no custom Factory is provided to the ViewModelProvider constructors. The Fragment's arguments when this is first called will be used as the defaults to any androidx.lifecycle.SavedStateHandle passed to a view model created using this factory. Any? getEnterTransition() Returns the Transition that will be used to move Views into the initial scene. The entering Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as entering is governed by changing visibility from View#INVISIBLE to View#VISIBLE. Any? getExitTransition() Returns the Transition that will be used to move Views out of the scene when the fragment is removed, hidden, or detached when not popping the back stack. The exiting Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as exiting is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If transition is null, the views will remain unaffected. FragmentManager? getFragmentManager() Return the FragmentManager for interacting with fragments associated with this fragment's activity. Note that this will be non-null slightly before getActivity(), during the time from when the fragment is placed in a FragmentTransaction until it is committed and attached to its activity. If this Fragment is a child of another Fragment, the FragmentManager returned here will be the parent's getChildFragmentManager(). Any? getHost() Return the host object of this fragment. May return null if the fragment isn't currently being hosted. Int getId() Return the identifier this fragment is known by. This is either the android:id value supplied in a layout or the container view ID supplied when adding the fragment. LayoutInflater getLayoutInflater() Returns the cached LayoutInflater used to inflate Views of this Fragment. If onGetLayoutInflater(Bundle) has not been called onGetLayoutInflater(Bundle) will be called with a null argument and that value will be cached. The cached LayoutInflater will be replaced immediately prior to onCreateView(LayoutInflater, ViewGroup, Bundle) and cleared immediately after onDetach(). Lifecycle getLifecycle() Returns the Lifecycle of the provider. Overriding this method is no longer supported and this method will be made final in a future version of Fragment. LoaderManager getLoaderManager() Return the LoaderManager for this fragment. Fragment?