ComponentCallbacks | Android Developers [proxy]

public interface ComponentCallbacks

android.content.ComponentCallbacks

Known indirect subclasses

AbstractInputMethodService, AccessibilityService, AccountAuthenticatorActivity, Activity, ActivityGroup, AliasActivity, Application, AutofillService, CallRedirectionService, CallScreeningService, CallStreamingService, CameraPrewarmService, CarrierMessagingClientService, CarrierMessagingService, CarrierService, and 57 others.

AbstractInputMethodService	AbstractInputMethodService provides a abstract base class for input methods.
AccessibilityService	Accessibility services should only be used to assist users with disabilities in using Android devices and apps.
AccountAuthenticatorActivity	This class was deprecated in API level 30. Applications should extend Activity themselves. This class is not compatible with AppCompat, and the functionality it provides is not complex.
Activity	An activity is a single, focused thing that the user can do.
ActivityGroup	This class was deprecated in API level 13. Use the new `Fragment` and `FragmentManager` APIs instead; these are also available on older platforms through the Android compatibility package.
AliasActivity	This class was deprecated in API level 30. Use `<activity-alias>` or subclass Activity directly.
Application	Base class for maintaining global application state.
AutofillService	An `AutofillService` is a service used to automatically fill the contents of the screen on behalf of a given user - for more information about autofill, read Autofill Framework.
CallRedirectionService	This service can be implemented to interact between Telecom and its implementor for making outgoing call with optional redirection/cancellation purposes.
CallScreeningService	This service can be implemented by the default dialer (see `TelecomManager#getDefaultDialerPackage()`) or a third party app to allow or disallow incoming calls before they are shown to a user.
CallStreamingService	This service is implemented by an app that wishes to provide functionality for a general call streaming sender for voip calls.
CameraPrewarmService	Extend this class to implement a camera prewarm service.
CarrierMessagingClientService	If the default SMS app has a service that extends this class, the system always tries to bind it so that the process is always running, which allows the app to have a persistent connection to the server.
CarrierMessagingService	A service that receives calls from the system when new SMS and MMS are sent or received.
CarrierService	A service that exposes carrier-specific functionality to the system.
ChooserTargetService	This class was deprecated in API level 30. For publishing direct share targets, please follow the instructions in https://developer.android.com/training/sharing/receive.html#providing-direct-share-targets instead.
CloudMediaProvider	Base class for a cloud media provider.
CompanionDeviceService	A service that receives calls from the system when the associated companion device appears nearby or is connected, as well as when the device is no longer "present" or connected.
ComponentCallbacks2	Extended `ComponentCallbacks` interface with a new callback for finer-grained memory management.
ConditionProviderService	This class was deprecated in API level 29. Instead of using an automatically bound service, use `NotificationManager.setAutomaticZenRuleState(String, Condition)` to tell the system about the state of your rule. In order to maintain a link from Settings to your rule configuration screens, provide a configuration activity that handles `NotificationManager.ACTION_AUTOMATIC_ZEN_RULE` on your `AutomaticZenRule` via `AutomaticZenRule.setConfigurationActivity(ComponentName)`.
ConnectionService	An abstract service that should be implemented by any apps which either: Can make phone calls (VoIP or otherwise) and want those calls to be integrated into the built-in phone app.
ContentProvider	Content providers are one of the primary building blocks of Android applications, providing content to applications.
ControlsProviderService	Service implementation allowing applications to contribute controls to the System UI.
CredentialProviderService	Service to be extended by credential providers, in order to return user credentials to the framework.
DeviceAdminService	Base class for a service that device owner/profile owners can optionally have.
DialogFragment	This class was deprecated in API level 28. Use the Support Library `DialogFragment` for consistent behavior across all devices and access to Lifecycle.
DocumentsProvider	Base class for a document provider.
DreamService	Extend this class to implement a custom dream (available to the user as a "Daydream").
ExpandableListActivity	This class was deprecated in API level 30. Use `RecyclerView` or use `ExpandableListView` directly
Fragment	This class was deprecated in API level 28. Use the Jetpack Fragment Library `Fragment` for consistent behavior across all devices and access to Lifecycle.
HostApduService	HostApduService is a convenience `Service` class that can be extended to emulate an NFC card inside an Android service component.
HostNfcFService	HostNfcFService is a convenience `Service` class that can be extended to emulate an NFC-F card inside an Android service component.
InCallService	This service is implemented by an app that wishes to provide functionality for managing phone calls.
InputMethodService	InputMethodService provides a standard implementation of an InputMethod, which final implementations can derive from and customize.
IntentService	This class was deprecated in API level 30. IntentService is subject to all the background execution limits imposed with Android 8.0 (API level 26). Consider using `WorkManager` instead.
JobService	Entry point for the callback from the `JobScheduler`.
LauncherActivity	This class was deprecated in API level 30. Applications can implement this UI themselves using `RecyclerView` and `PackageManager.queryIntentActivities(Intent, int)`
ListActivity	This class was deprecated in API level 30. Use `ListFragment` or `RecyclerView` to implement your Activity instead.
ListFragment	This class was deprecated in API level 28. Use the Support Library `ListFragment` for consistent behavior across all devices and access to Lifecycle.
MediaBrowserService	Base class for media browser services.
MediaRoute2ProviderService	Base class for media route provider services.
MediaSession2Service	This API is not generally intended for third party application developers.
MidiDeviceService	A service that implements a virtual MIDI device.
MockApplication	This class was deprecated in API level 24. Use a mocking framework like Mockito. New tests should be written using the Android Testing Support Library.
MockContentProvider	Mock implementation of ContentProvider.
NativeActivity	Convenience for implementing an activity that will be implemented purely in native code.
NotificationListenerService	A service that receives calls from the system when new notifications are posted or removed, or their ranking changed.
OffHostApduService	OffHostApduService is a convenience `Service` class that can be extended to describe one or more NFC applications that are residing off-host, for example on an embedded secure element or a UICC.
PreferenceActivity	This class was deprecated in API level 29. Use the AndroidX Preference Library for consistent behavior across all devices. For more information on using the AndroidX Preference Library see Settings.
PreferenceFragment	This class was deprecated in API level 28. Use the AndroidX Preference Library for consistent behavior across all devices. For more information on using the AndroidX Preference Library see Settings.
PrintService	This is the base class for implementing print services.
QuickAccessWalletService	A `QuickAccessWalletService` provides a list of `WalletCard`s shown in the Quick Access Wallet.
RecognitionService	This class provides a base class for recognition service implementations.
RemoteViewsService	The service to be connected to for a remote adapter to request RemoteViews.
SearchRecentSuggestionsProvider	This superclass can be used to create a simple search suggestions provider for your application.
Service	A Service is an application component representing either an application's desire to perform a longer-running operation while not interacting with the user or to supply functionality for other applications to use.
SettingInjectorService	Dynamically specifies the summary (subtitle) and enabled status of a preference injected into the list of app settings displayed by the system settings app For use only by apps that are included in the system image, for preferences that affect multiple apps.
SliceProvider	A SliceProvider allows an app to provide content to be displayed in system spaces.
SpellCheckerService	SpellCheckerService provides an abstract base class for a spell checker.
TabActivity	This class was deprecated in API level 13. New applications should use Fragments instead of this class; to continue to run on older devices, you can use the v4 support library which provides a version of the Fragment API that is compatible down to `Build.VERSION_CODES.DONUT`.
TextToSpeechService	Abstract base class for TTS engine implementations.
TileService	A TileService provides the user a tile that can be added to Quick Settings.
TvInputService	The TvInputService class represents a TV input or source such as HDMI or built-in tuner which provides pass-through video or broadcast TV programs.
TvInteractiveAppService	A TV interactive application service is a service that provides runtime environment and runs TV interactive applications.
VisualVoicemailService	This service is implemented by dialer apps that wishes to handle OMTP or similar visual voicemails.
VoiceInteractionService	Top-level service of the current global voice interactor, which is providing support for hotwording, the back-end of a `VoiceInteractor`, etc.
VoiceInteractionSession	An active voice interaction session, providing a facility for the implementation to interact with the user in the voice interaction layer.
VoiceInteractionSessionService	An active voice interaction session, initiated by a `VoiceInteractionService`.
VpnService	VpnService is a base class for applications to extend and build their own VPN solutions.
VrListenerService	A service that is bound from the system while running in virtual reality (VR) mode.
WallpaperService	A wallpaper service is responsible for showing a live wallpaper behind applications that would like to sit on top of it.
WebViewFragment	This class was deprecated in API level 28. Manually call `WebView#onPause()` and `WebView#onResume()`

The set of callback APIs that are common to all application components (Activity, Service, ContentProvider, and Application).

Note: You should also implement the ComponentCallbacks2 interface, which provides the ComponentCallbacks2.onTrimMemory(int) callback to help your app manage its memory usage more effectively.

Summary

Public methods
`abstract void`	`onConfigurationChanged(Configuration newConfig)` Called by the system when the device configuration changes while your component is running.
`abstract void`	`onLowMemory()` This is called when the overall system is running low on memory, and actively running processes should trim their memory usage.

Public methods

onConfigurationChanged

public abstract void onConfigurationChanged (Configuration newConfig)

Called by the system when the device configuration changes while your component is running. Note that, unlike activities, other components are never restarted when a configuration changes: they must always deal with the results of the change, such as by re-retrieving resources.

At the time that this function has been called, your Resources object will have been updated to return resource values matching the new configuration.

For more information, read Handling Runtime Changes.

Parameters
`newConfig`	`Configuration`: The new device configuration. This value cannot be `null`.

onLowMemory

public abstract void onLowMemory ()

This is called when the overall system is running low on memory, and actively running processes should trim their memory usage. While the exact point at which this will be called is not defined, generally it will happen when all background process have been killed. That is, before reaching the point of killing processes hosting service and foreground UI that we would like to avoid killing.

You should implement this method to release any caches or other unnecessary resources you may be holding on to. The system will perform a garbage collection for you after returning from this method.

Preferably, you should implement ComponentCallbacks2#onTrimMemory from ComponentCallbacks2 to incrementally unload your resources based on various levels of memory demands. That API is available for API level 14 and higher, so you should only use this onLowMemory() method as a fallback for older versions, which can be treated the same as ComponentCallbacks2#onTrimMemory with the ComponentCallbacks2.TRIM_MEMORY_COMPLETE level.