ComponentActivity

Kotlin |Java

open class ComponentActivity : ComponentActivity, LifecycleOwner, ViewModelStoreOwner, HasDefaultViewModelProviderFactory, SavedStateRegistryOwner, OnBackPressedDispatcherOwner

androidx.activity.ComponentActivity

Known Direct Subclasses FragmentActivity FragmentActivity Base class for activities that want to use the support-based Fragments.

Known Indirect Subclasses AppCompatActivity AppCompatActivity Base class for activities that use the support library action bar features.

Base class for activities that enables composition of higher level components.

Rather than all functionality being built directly into this class, only the minimal set of lower level building blocks are included. Higher level components can then be used as needed without enforcing a deep Activity class hierarchy or strong coupling between components.

Summary

Public constructors
<init>() Default constructor for ComponentActivity.
<init>(@LayoutRes contentLayoutId: Int) Alternate constructor that can be used to provide a default layout that will be inflated as part of super.onCreate(savedInstanceState).

Public methods
open ViewModelProvider.Factory	getDefaultViewModelProviderFactory() Returns the default ViewModelProvider.Factory that should be used when no custom Factory is provided to the ViewModelProvider constructors.
open Any?	getLastCustomNonConfigurationInstance() Return the value previously returned from onRetainCustomNonConfigurationInstance().
open Lifecycle	getLifecycle() Returns the Lifecycle of the provider.
OnBackPressedDispatcher	getOnBackPressedDispatcher() Retrieve the OnBackPressedDispatcher that will be triggered when onBackPressed() is called.
SavedStateRegistry	getSavedStateRegistry()
open ViewModelStore	getViewModelStore() Returns the ViewModelStore associated with this activity
open Unit	onBackPressed() Called when the activity has detected the user's press of the back key.
open Any?	onRetainCustomNonConfigurationInstance() Use this instead of onRetainNonConfigurationInstance().
Any?	onRetainNonConfigurationInstance() Retain all appropriate non-config state.

Protected methods
open Unit	onCreate(@Nullable savedInstanceState: Bundle?) If your ComponentActivity is annotated with ContentView, this will call setContentView(int) for you.
open Unit	onSaveInstanceState(@NonNull outState: Bundle)

Extension functions
From androidx.activity Lazy<VM> ComponentActivity.viewModels(noinline factoryProducer: () -> ViewModelProvider.Factory = null) Returns a Lazy delegate to access the ComponentActivity's ViewModel, if factoryProducer is specified then ViewModelProvider.Factory returned by it will be used to create ViewModel first time.

Public constructors

<init>

ComponentActivity()

Default constructor for ComponentActivity. All Activities must have a default constructor for API 27 and lower devices or when using the default android.app.AppComponentFactory.

<init>

ComponentActivity(@LayoutRes contentLayoutId: Int)

Alternate constructor that can be used to provide a default layout that will be inflated as part of super.onCreate(savedInstanceState).

This should generally be called from your constructor that takes no parameters, as is required for API 27 and lower or when using the default android.app.AppComponentFactory.

See Also

• #ComponentActivity()

Public methods

getDefaultViewModelProviderFactory

@NonNull open fun getDefaultViewModelProviderFactory(): ViewModelProvider.Factory

Returns the default ViewModelProvider.Factory that should be used when no custom Factory is provided to the ViewModelProvider constructors.

The extras of getIntent() 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.

Return
ViewModelProvider.Factory: a ViewModelProvider.Factory

getLastCustomNonConfigurationInstance

@Nullable open fun getLastCustomNonConfigurationInstance(): Any?

Deprecated: Use a androidx.lifecycle.ViewModel to store non config state.

Return the value previously returned from onRetainCustomNonConfigurationInstance().

getLifecycle

@NonNull open fun getLifecycle(): Lifecycle

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 ComponentActivity. If you do override this method, you must:

1. Return an instance of LifecycleRegistry
2. Lazily initialize your LifecycleRegistry object when this is first called. Note that this method will be called in the super classes' constructor, before any field initialization or object state creation is complete.

Return
Lifecycle: The lifecycle of the provider.

getOnBackPressedDispatcher

@NonNull fun getOnBackPressedDispatcher(): OnBackPressedDispatcher

Retrieve the OnBackPressedDispatcher that will be triggered when onBackPressed() is called.

Return
OnBackPressedDispatcher: The OnBackPressedDispatcher associated with this ComponentActivity.

getSavedStateRegistry

@NonNull fun getSavedStateRegistry(): SavedStateRegistry

getViewModelStore

@NonNull open fun getViewModelStore(): ViewModelStore

Returns the ViewModelStore associated with this activity

Overriding this method is no longer supported and this method will be made final in a future version of ComponentActivity.

Return
ViewModelStore: a ViewModelStore

Exceptions
IllegalStateException	if called before the Activity is attached to the Application instance i.e., before onCreate()

onBackPressed

@MainThread open fun onBackPressed(): Unit

Called when the activity has detected the user's press of the back key. The OnBackPressedDispatcher will be given a chance to handle the back button before the default behavior of android.app.Activity#onBackPressed() is invoked.

See Also

• #getOnBackPressedDispatcher()

onRetainCustomNonConfigurationInstance

@Nullable open fun onRetainCustomNonConfigurationInstance(): Any?

Deprecated: Use a androidx.lifecycle.ViewModel to store non config state.

Use this instead of onRetainNonConfigurationInstance(). Retrieve later with getLastCustomNonConfigurationInstance().

onRetainNonConfigurationInstance

@Nullable fun onRetainNonConfigurationInstance(): Any?

Retain all appropriate non-config state. You can NOT override this yourself! Use a androidx.lifecycle.ViewModel if you want to retain your own non config state.

Protected methods

onCreate

protected open fun onCreate(@Nullable savedInstanceState: Bundle?): Unit

If your ComponentActivity is annotated with ContentView, this will call setContentView(int) for you.

onSaveInstanceState

@CallSuper protected open fun onSaveInstanceState(@NonNull outState: Bundle): Unit