Callback

Kotlin |Java

interface Callback

android.graphics.drawable.Drawable.Callback

Known Direct Subclasses

AdaptiveIconDrawable, ColorStateListDrawable, DrawableContainer, DrawableWrapper, LayerDrawable, TransitionDrawable, View

AdaptiveIconDrawable	This class can also be created via XML inflation using `<adaptive-icon>` tag in addition to dynamic creation.
ColorStateListDrawable	A Drawable that manages a `ColorDrawable` to make it stateful and backed by a `ColorStateList`.
DrawableContainer	A helper class that contains several `Drawable`s and selects which one to use.
DrawableWrapper	Drawable container with only one child element.
LayerDrawable	A Drawable that manages an array of other Drawables.
TransitionDrawable	An extension of LayerDrawables that is intended to cross-fade between the first and second layer.
View	This class represents the basic building block for user interface components.

Known Indirect Subclasses

AbsListView, AbsSeekBar, AbsSpinner, AbsoluteLayout, ActionMenuView, AdapterView, AdapterViewAnimator, AdapterViewFlipper, AnalogClock, AnimatedStateListDrawable, AnimationDrawable, AppWidgetHostView, and 80 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	A layout that lets you specify exact locations (x/y coordinates) of its children.
ActionMenuView	ActionMenuView is a presentation of a series of menu options as a View.
AdapterView	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.
AnalogClock	This widget displays an analogic clock with two hands for hours and minutes.
AnimatedStateListDrawable	Drawable containing a set of Drawable keyframes where the currently displayed keyframe is chosen based on the current state set.
AnimationDrawable	An object used to create frame-by-frame animations, defined by a series of Drawable objects, which can be used as a View object's background.
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.
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.
ClipDrawable	A Drawable that clips another Drawable based on this Drawable's current level value.
CompoundButton	A button with two states, checked and unchecked.
DatePicker	Provides a widget for selecting a date.
DialerFilter	This widget is a layout that contains several specifically-named child views that handle keyboard entry interpreted as standard phone dialpad digits.
DigitalClock	Like AnalogClock, but digital.
EditText	A user interface element for entering and modifying text.
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	Helper class for showing "bread crumbs" representing the fragment stack in an activity.
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	A view that shows items in a center-locked, horizontally scrolling list.
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 `android.graphics.Bitmap` or `android.graphics.drawable.Drawable` resources.
InlineContentView	This class represents a view that holds opaque content from another app that you can inline in your UI.
InsetDrawable	A Drawable that insets another Drawable by a specified distance or fraction of the content bounds.
KeyboardView	A view that renders a virtual `Keyboard`.
LevelListDrawable	A resource that manages a number of alternate Drawables, each assigned a maximum numerical value.
LinearLayout	A layout that arranges other views either horizontally in a single column or vertically in a single row.
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.
NumberPicker	A widget that enables the user to select a number from a predefined range.
ProgressBar	A user interface element that indicates the progress of an operation.
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.
RippleDrawable	Drawable that shows a ripple effect in response to state changes.
RotateDrawable	A Drawable that can rotate another Drawable based on the current level value.
ScaleDrawable	A Drawable that changes the size of another Drawable based on its current level value.
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	SlidingDrawer hides content out of the screen and allows the user to drag a handle to bring the content on screen.
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
StateListDrawable	Lets you assign a number of graphic images to a single Drawable and swap out the visible item by a string ID value.
SurfaceView	Provides a dedicated drawing surface embedded inside of a view hierarchy.
Switch	A Switch is a two-state toggle widget.
TabHost	Container for a tabbed window view.
TabWidget	Displays a list of tab labels representing each page in the parent's tab collection.
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 `android.widget.ViewSwitcher` that contains only children of type `android.widget.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.
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.
TransitionDrawable	An extension of LayerDrawables that is intended to cross-fade between the first and second layer.
TvAdView	Displays contents of TV advertisement services.
TvInteractiveAppView	Displays contents of interactive TV applications.
TvView	Displays TV contents.
TwoLineListItem	A view group with two children, intended for use in ListViews.
VideoView	Displays a video file.
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.
WebView	A View that displays web pages.
ZoomButton	This widget provides a simple utility for turning a continued long-press event into a series of clicks at some set frequency.
ZoomControls	The `ZoomControls` class displays a simple set of controls used for zooming and provides callbacks to register for events.

Implement this interface if you want to create an animated drawable that extends Drawable. Upon retrieving a drawable, use Drawable.setCallback(android.graphics.drawable.Drawable.Callback) to supply your implementation of the interface to the drawable; it uses this interface to schedule and execute animation changes.

Summary

Public methods
abstract Unit	`invalidateDrawable(who: Drawable)` Called when the drawable needs to be redrawn.
abstract Unit	`scheduleDrawable(who: Drawable, what: Runnable, when: Long)` A Drawable can call this to schedule the next frame of its animation.
abstract Unit	`unscheduleDrawable(who: Drawable, what: Runnable)` A Drawable can call this to unschedule an action previously scheduled with `scheduleDrawable`.

Public methods

invalidateDrawable

Added in API level 1

abstract fun invalidateDrawable(who: Drawable): Unit

Called when the drawable needs to be redrawn. A view at this point should invalidate itself (or at least the part of itself where the drawable appears).

Parameters
`who`	Drawable: The drawable that is requesting the update. This value cannot be `null`.

scheduleDrawable

Added in API level 1

abstract fun scheduleDrawable(
    who: Drawable, 
    what: Runnable, 
    when: Long
): Unit

A Drawable can call this to schedule the next frame of its animation. An implementation can generally simply call android.os.Handler#postAtTime(Runnable, Object, long) with the parameters (what, who, when) to perform the scheduling.

Parameters
`who`	Drawable: The drawable being scheduled. This value cannot be `null`.
`what`	Runnable: The action to execute. This value cannot be `null`.
`when`	Long: The time (in milliseconds) to run. The timebase is `android.os.SystemClock#uptimeMillis`

unscheduleDrawable

Added in API level 1

abstract fun unscheduleDrawable(
    who: Drawable, 
    what: Runnable
): Unit

A Drawable can call this to unschedule an action previously scheduled with scheduleDrawable. An implementation can generally simply call android.os.Handler#removeCallbacks(Runnable, Object) with the parameters (what, who) to unschedule the drawable.

Parameters
`who`	Drawable: The drawable being unscheduled. This value cannot be `null`.
`what`	Runnable: The action being unscheduled. This value cannot be `null`.