KeyEvent.Callback

Kotlin |Java

public static interface KeyEvent.Callback

android.view.KeyEvent.Callback

Known indirect subclasses

AbsListView, AbsSeekBar, AbsSpinner, AbsoluteLayout, AbstractInputMethodService, AccountAuthenticatorActivity, ActionMenuView, Activity, ActivityGroup, AdapterView<T extends Adapter>, AdapterViewAnimator, AdapterViewFlipper, AlertDialog, AliasActivity, AnalogClock, and 90 others.

AbsListView	Base class that can be used to implement virtualized lists of items.
AbsSeekBar	AbsSeekBar extends the capabilities of ProgressBar by adding a draggable thumb.
AbsSpinner	An abstract base class for spinner widgets.
AbsoluteLayout	This class was deprecated in API level 3. Use `FrameLayout`, `RelativeLayout` or a custom layout instead.
AbstractInputMethodService	AbstractInputMethodService provides a abstract base class for input methods.
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.
ActionMenuView	ActionMenuView is a presentation of a series of menu options as a View.
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.
AdapterView<T extends Adapter>	An AdapterView is a view whose children are determined by an `Adapter`.
AdapterViewAnimator	Base class for a `AdapterView` that will perform animations when switching between its views.
AdapterViewFlipper	Simple `ViewAnimator` that will animate between two or more views that have been added to it.
AlertDialog	A subclass of Dialog that can display one, two or three buttons.
AliasActivity	This class was deprecated in API level 30. Use `<activity-alias>` or subclass Activity directly.
AnalogClock	This class was deprecated in API level 23. This widget is no longer supported; except for `RemoteViews` use cases like app widgets.
AppWidgetHostView	Provides the glue to show AppWidget views.
AutoCompleteTextView	An editable text view that shows completion suggestions automatically while the user is typing.
Button	A user interface element the user can tap or click to perform an action.
CalendarView	This class is a calendar widget for displaying and selecting dates.
CharacterPickerDialog	Dialog for choosing accented characters related to a base character.
CheckBox	A checkbox is a specific type of two-states button that can be either checked or unchecked.
CheckedTextView	An extension to `TextView` that supports the `Checkable` interface and displays.
Chronometer	Class that implements a simple timer.
CompoundButton	A button with two states, checked and unchecked.
DatePicker	Provides a widget for selecting a date.
DatePickerDialog	A simple dialog containing an `DatePicker`.
DialerFilter	This class was deprecated in API level 26. Use a custom view or layout to handle this functionality instead
Dialog	Base class for Dialogs.
DigitalClock	This class was deprecated in API level 17. It is recommended you use `TextClock` instead.
EditText	A user interface element for entering and modifying text.
ExpandableListActivity	This class was deprecated in API level 30. Use `RecyclerView` or use `ExpandableListView` directly
ExpandableListView	A view that shows items in a vertically scrolling two-level list.
ExtractEditText	Specialization of `EditText` for showing and interacting with the extracted text in a full-screen input method.
FragmentBreadCrumbs	This class was deprecated in API level 21. This widget is no longer supported.
FrameLayout	FrameLayout is designed to block out an area on the screen to display a single item.
GLSurfaceView	An implementation of SurfaceView that uses the dedicated surface for displaying OpenGL rendering.
Gallery	This class was deprecated in API level 16. This widget is no longer supported. Other horizontally scrolling widgets include `HorizontalScrollView` and `ViewPager` from the support library.
GestureOverlayView	A transparent overlay for gesture input that can be placed on top of other widgets or contain other widgets.
GridLayout	A layout that places its children in a rectangular grid.
GridView	A view that shows items in two-dimensional scrolling grid.
HorizontalScrollView	Layout container for a view hierarchy that can be scrolled by the user, allowing it to be larger than the physical display.
ImageButton	Displays a button with an image (instead of text) that can be pressed or clicked by the user.
ImageSwitcher	`ViewSwitcher` that switches between two ImageViews when a new image is set on it.
ImageView	Displays image resources, for example `Bitmap` or `Drawable` resources.
InlineContentView	This class represents a view that holds opaque content from another app that you can inline in your UI.
InputMethodService	InputMethodService provides a standard implementation of an InputMethod, which final implementations can derive from and customize.
KeyboardView	This class was deprecated in API level 29. This class is deprecated because this is just a convenient UI widget class that application developers can re-implement on top of existing public APIs. If you have already depended on this class, consider copying the implementation from AOSP into your project or re-implementing a similar widget by yourselves
LauncherActivity	This class was deprecated in API level 30. Applications can implement this UI themselves using `RecyclerView` and `PackageManager.queryIntentActivities(Intent, int)`
LinearLayout	A layout that arranges other views either horizontally in a single column or vertically in a single row.
ListActivity	This class was deprecated in API level 30. Use `ListFragment` or `RecyclerView` to implement your Activity instead.
ListView	Displays a vertically-scrollable collection of views, where each view is positioned immediatelybelow the previous view in the list.
MediaController	A view containing controls for a MediaPlayer.
MediaRouteButton
MultiAutoCompleteTextView	An editable text view, extending `AutoCompleteTextView`, that can show completion suggestions for the substring of the text where the user is typing instead of necessarily for the entire thing.
NativeActivity	Convenience for implementing an activity that will be implemented purely in native code.
NumberPicker	A widget that enables the user to select a number from a predefined range.
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.
Presentation	Base class for presentations.
ProgressBar	A user interface element that indicates the progress of an operation.
ProgressDialog	This class was deprecated in API level 26. `ProgressDialog` is a modal dialog, which prevents the user from interacting with the app. Instead of using this class, you should use a progress indicator like `ProgressBar`, which can be embedded in your app's UI. Alternatively, you can use a notification to inform the user of the task's progress.
QuickContactBadge	Widget used to show an image with the standard QuickContact badge and on-click behavior.
RadioButton	A radio button is a two-states button that can be either checked or unchecked.
RadioGroup	This class is used to create a multiple-exclusion scope for a set of radio buttons.
RatingBar	A RatingBar is an extension of SeekBar and ProgressBar that shows a rating in stars.
RelativeLayout	A Layout where the positions of the children can be described in relation to each other or to the parent.
ScrollView	A view group that allows the view hierarchy placed within it to be scrolled.
SearchView	A widget that provides a user interface for the user to enter a search query and submit a request to a search provider.
SeekBar	A SeekBar is an extension of ProgressBar that adds a draggable thumb.
SlidingDrawer	This class was deprecated in API level 17. This class is not supported anymore. It is recommended you base your own implementation on the source code for the Android Open Source Project if you must use it in your application.
Space	Space is a lightweight View subclass that may be used to create gaps between components in general purpose layouts.
Spinner	A view that displays one child at a time and lets the user pick among them.
SplashScreenView	The view which allows an activity to customize its splash screen exit animation.
StackView
SurfaceView	Provides a dedicated drawing surface embedded inside of a view hierarchy.
Switch	A Switch is a two-state toggle widget.
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`.
TabHost	This class was deprecated in API level 30. new applications should use fragment APIs instead of this class: Use TabLayout and ViewPager instead.
TabWidget	This class was deprecated in API level 30. new applications should use fragment APIs instead of this class: Use TabLayout and ViewPager instead.
TableLayout	A layout that arranges its children into rows and columns.
TableRow	A layout that arranges its children horizontally.
TextClock	`TextClock` can display the current date and/or time as a formatted string.
TextSwitcher	Specialized `ViewSwitcher` that contains only children of type `TextView`.
TextView	A user interface element that displays text to the user.
TextureView	A TextureView can be used to display a content stream, such as that coming from a camera preview, a video, or an OpenGL scene.
TimePicker	A widget for selecting the time of day, in either 24-hour or AM/PM mode.
TimePickerDialog	A dialog that prompts the user for the time of day using a `TimePicker`.
ToggleButton	Displays checked/unchecked states as a button with a "light" indicator and by default accompanied with the text "ON" or "OFF".
Toolbar	A standard toolbar for use within application content.
TvInputService.HardwareSession	Base class for a TV input session which represents an external device connected to a hardware TV input.
TvInputService.Session	Base class for derived classes to implement to provide a TV input session.
TvInteractiveAppService.Session	Base class for derived classes to implement to provide a TV interactive app session.
TvInteractiveAppView	Displays contents of interactive TV applications.
TvView	Displays TV contents.
TwoLineListItem	This class was deprecated in API level 17. This class can be implemented easily by apps using a `RelativeLayout` or a `LinearLayout`.
VideoView	Displays a video file.
View	This class represents the basic building block for user interface components.
ViewAnimator	Base class for a `FrameLayout` container that will perform animations when switching between its views.
ViewFlipper	Simple `ViewAnimator` that will animate between two or more views that have been added to it.
ViewGroup	A `ViewGroup` is a special view that can contain other views (called children.) The view group is the base class for layouts and views containers.
ViewStub	A ViewStub is an invisible, zero-sized View that can be used to lazily inflate layout resources at runtime.
ViewSwitcher	`ViewAnimator` that switches between two views, and has a factory from which these views are created.
VoiceInteractionSession	An active voice interaction session, providing a facility for the implementation to interact with the user in the voice interaction layer.
WebView	A View that displays web pages.
ZoomButton	This class was deprecated in API level 26. Use other means to handle this functionality. This widget is merely a simple wrapper around a long-press handler.
ZoomControls	This class was deprecated in API level 29. This functionality and UI is better handled with custom views and layouts rather than a dedicated zoom-control widget

Summary

Public methods
`abstract boolean`	`onKeyDown(int keyCode, KeyEvent event)` Called when a key down event has occurred.
`abstract boolean`	`onKeyLongPress(int keyCode, KeyEvent event)` Called when a long press has occurred.
`abstract boolean`	`onKeyMultiple(int keyCode, int count, KeyEvent event)` Called when a user's interaction with an analog control, such as flinging a trackball, generates simulated down/up events for the same key multiple times in quick succession.
`abstract boolean`	`onKeyUp(int keyCode, KeyEvent event)` Called when a key up event has occurred.

Public methods

onKeyDown

Added in API level 1

public abstract boolean onKeyDown (int keyCode, 
                KeyEvent event)

Called when a key down event has occurred. If you return true, you can first call KeyEvent.startTracking() to have the framework track the event through its onKeyUp(int, android.view.KeyEvent) and also call your onKeyLongPress(int, android.view.KeyEvent) if it occurs.

Parameters
`keyCode`	`int`: The value in event.getKeyCode().
`event`	`KeyEvent`: Description of the key event.

Returns
`boolean`	If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

onKeyLongPress

Added in API level 5

public abstract boolean onKeyLongPress (int keyCode, 
                KeyEvent event)

Called when a long press has occurred. If you return true, the final key up will have KeyEvent#FLAG_CANCELED and KeyEvent#FLAG_CANCELED_LONG_PRESS set. Note that in order to receive this callback, someone in the event change must return true from onKeyDown(int, KeyEvent) and call KeyEvent#startTracking() on the event.

Parameters
`keyCode`	`int`: The value in event.getKeyCode().
`event`	`KeyEvent`: Description of the key event.

Returns
`boolean`	If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

onKeyMultiple

Added in API level 1

public abstract boolean onKeyMultiple (int keyCode, 
                int count, 
                KeyEvent event)

Called when a user's interaction with an analog control, such as flinging a trackball, generates simulated down/up events for the same key multiple times in quick succession.

Parameters
`keyCode`	`int`: The value in event.getKeyCode().
`count`	`int`: Number of pairs as returned by event.getRepeatCount().
`event`	`KeyEvent`: Description of the key event.

Returns
`boolean`	If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

onKeyUp

Added in API level 1

public abstract boolean onKeyUp (int keyCode, 
                KeyEvent event)

Called when a key up event has occurred.

Parameters
`keyCode`	`int`: The value in event.getKeyCode().
`event`	`KeyEvent`: Description of the key event.

Returns
`boolean`	If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.