AnimationDrawable
open class AnimationDrawable : DrawableContainer, Runnable, Animatable
kotlin.Any | |||
↳ | android.graphics.drawable.Drawable | ||
↳ | android.graphics.drawable.DrawableContainer | ||
↳ | android.graphics.drawable.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.
The simplest way to create a frame-by-frame animation is to define the animation in an XML file, placed in the res/drawable/ folder, and set it as the background to a View object. Then, call start()
to run the animation.
An AnimationDrawable defined in XML consists of a single <animation-list>
element and a series of nested <item>
tags. Each item defines a frame of the animation. See the example below.
spin_animation.xml file in res/drawable/ folder:
<!-- Animation frames are wheel0.png through wheel5.png files inside the res/drawable/ folder --> <animation-list android:id="@+id/selected" android:oneshot="false"> <item android:drawable="@drawable/wheel0" android:duration="50" /> <item android:drawable="@drawable/wheel1" android:duration="50" /> <item android:drawable="@drawable/wheel2" android:duration="50" /> <item android:drawable="@drawable/wheel3" android:duration="50" /> <item android:drawable="@drawable/wheel4" android:duration="50" /> <item android:drawable="@drawable/wheel5" android:duration="50" /> </animation-list>
Here is the code to load and play this animation.
// Load the ImageView that will host the animation and // set its background to our AnimationDrawable XML resource. ImageView img = (ImageView)findViewById(R.id.spinning_wheel_image); img.setBackgroundResource(R.drawable.spin_animation); // Get the background, which has been compiled to an AnimationDrawable object. AnimationDrawable frameAnimation = (AnimationDrawable) img.getBackground(); // Start the animation (looped playback by default). frameAnimation.start();
Summary
XML attributes | |
---|---|
android:drawable |
Reference to a drawable resource to use for the frame. |
android:duration |
Amount of time (in milliseconds) to display this frame. |
android:oneshot |
If true, the animation will only run a single time and then stop. |
android:variablePadding |
If true, allows the drawable's padding to change based on the current state that is selected. |
android:visible |
Provides initial visibility state of the drawable; the default value is false. |
Public constructors | |
---|---|
Public methods | |
---|---|
open Unit |
Adds a frame to the animation |
open Int |
getDuration(i: Int) |
open Drawable! | |
open Int | |
open Unit |
inflate(r: Resources, parser: XmlPullParser, attrs: AttributeSet, theme: Resources.Theme?) |
open Boolean | |
open Boolean |
Indicates whether the animation is currently running or not. |
open Drawable |
mutate() Make this drawable mutable. |
open Unit |
run() This method exists for implementation purpose only and should not be called directly. |
open Unit |
setOneShot(oneShot: Boolean) Sets whether the animation should play once or repeat. |
open Boolean |
setVisible(visible: Boolean, restart: Boolean) Sets whether this AnimationDrawable is visible. |
open Unit |
start() Starts the animation from the first frame, looping if necessary. |
open Unit |
stop() Stops the animation at the current frame. |
open Unit |
unscheduleSelf(what: Runnable) |
Protected methods | |
---|---|
open Unit |
Inherited functions | |
---|---|
XML attributes
android:drawable
android:drawable
May be a reference to another resource, in the form "@[+][package:]type/name
" or a theme attribute in the form "?[package:]type/name
".
android:duration
android:duration
May be an integer value, such as "100
".
android:oneshot
android:oneshot
May be a boolean value, such as "true
" or "false
".
android:variablePadding
android:variablePadding
May be a boolean value, such as "true
" or "false
".
android:visible
android:visible
android.graphics.drawable.Drawable#setVisible
.
May be a boolean value, such as "true
" or "false
".
Public constructors
Public methods
addFrame
open fun addFrame(
frame: Drawable,
duration: Int
): Unit
Adds a frame to the animation
Parameters | |
---|---|
frame |
Drawable: The frame to add This value cannot be null . |
duration |
Int: How long in milliseconds the frame should appear |
getDuration
open fun getDuration(i: Int): Int
Return | |
---|---|
Int |
The duration in milliseconds of the frame at the specified index |
getFrame
open fun getFrame(index: Int): Drawable!
Return | |
---|---|
Drawable! |
The Drawable at the specified frame index |
getNumberOfFrames
open fun getNumberOfFrames(): Int
Return | |
---|---|
Int |
The number of frames in the animation |
inflate
open fun inflate(
r: Resources,
parser: XmlPullParser,
attrs: AttributeSet,
theme: Resources.Theme?
): Unit
Parameters | |
---|---|
r |
Resources: Resources used to resolve attribute values This value cannot be null . |
parser |
XmlPullParser: XML parser from which to inflate this Drawable This value cannot be null . |
attrs |
AttributeSet: Base set of attribute values This value cannot be null . |
theme |
Resources.Theme?: Theme to apply, may be null |
Exceptions | |
---|---|
org.xmlpull.v1.XmlPullParserException |
|
java.io.IOException |
isOneShot
open fun isOneShot(): Boolean
Return | |
---|---|
Boolean |
True of the animation will play once, false otherwise |
isRunning
open fun isRunning(): Boolean
Indicates whether the animation is currently running or not.
Return | |
---|---|
Boolean |
true if the animation is running, false otherwise |
mutate
open fun mutate(): Drawable
Make this drawable mutable. This operation cannot be reversed. A mutable drawable is guaranteed to not share its state with any other drawable. This is especially useful when you need to modify properties of drawables loaded from resources. By default, all drawables instances loaded from the same resource share a common state; if you modify the state of one instance, all the other instances will receive the same modification. Calling this method on a mutable Drawable will have no effect.
Return | |
---|---|
Drawable |
This value cannot be null . |
run
open fun run(): Unit
This method exists for implementation purpose only and should not be called directly. Invoke start()
instead.
See Also
setOneShot
open fun setOneShot(oneShot: Boolean): Unit
Sets whether the animation should play once or repeat.
Parameters | |
---|---|
oneShot |
Boolean: Pass true if the animation should only play once |
setVisible
open fun setVisible(
visible: Boolean,
restart: Boolean
): Boolean
Sets whether this AnimationDrawable is visible.
When the drawable becomes invisible, it will pause its animation. A subsequent change to visible with restart
set to true will restart the animation from the first frame. If restart
is false, the drawable will resume from the most recent frame. If the drawable has already reached the last frame, it will then loop back to the first frame, unless it's a one shot drawable (set through setOneShot(boolean)
), in which case, it will stay on the last frame.
Parameters | |
---|---|
visible |
Boolean: true if visible, false otherwise |
restart |
Boolean: when visible, true to force the animation to restart from the first frame |
Return | |
---|---|
Boolean |
true if the new visibility is different than its previous state |
start
open fun start(): Unit
Starts the animation from the first frame, looping if necessary. This method has no effect if the animation is running.
Note: Do not call this in the android.app.Activity#onCreate method of your activity, because the AnimationDrawable
is not yet fully attached to the window. If you want to play the animation immediately without requiring interaction, then you might want to call it from the android.app.Activity#onWindowFocusChanged
method in your activity, which will get called when Android brings your window into focus.
See Also
stop
open fun stop(): Unit
Stops the animation at the current frame. This method has no effect if the animation is not running.
See Also
unscheduleSelf
open fun unscheduleSelf(what: Runnable): Unit
Parameters | |
---|---|
what |
Runnable: The runnable that you no longer want called. This value cannot be null . |
Protected methods
setConstantState
protected open fun setConstantState(state: DrawableContainer.DrawableContainerState): Unit
Parameters | |
---|---|
state |
DrawableContainer.DrawableContainerState: This value cannot be null . |