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.
// 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();
Return a mask of the configuration parameters for which this drawable may change, requiring that it be re-created. The default implementation returns whatever was provided through setChangingConfigurations(int) or 0 by default. Subclasses may extend this to or in the changing configurations of any other drawables they hold.
The default behavior defines the outline to be the bounding rectangle of 0 alpha. Subclasses that wish to convey a different shape or alpha value must override this method.
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).
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.
Return a copy of the drawable's bounds in the specified Rect (allocated by the caller). The bounds specify where this will draw when its draw() method is called.
Return a copy of the drawable's bounds in a new Rect. This returns the same values as getBounds(), but the returned object is guaranteed to not be changed later by the drawable (i.e. it retains no reference to this rect). If the caller already has a Rect allocated, call copyBounds(rect).
Create from inside an XML document. Called on a parser positioned at a tag in an XML document, tries to create a Drawable from that tag. Returns null if the tag is not a valid drawable.
Create a drawable from inside an XML document using an optional Theme. Called on a parser positioned at a tag in an XML document, tries to create a Drawable from that tag. Returns null if the tag is not a valid drawable.
Return the drawable's bounds Rect. Note: for efficiency, the returned object may be the same object stored in the drawable (though this is not guaranteed), so if a persistent copy of the bounds is needed, call copyBounds(rect) instead. You should also not change the object returned by this method as it may be the same object stored in the drawable.
Return the drawable's dirty bounds Rect. Note: for efficiency, the returned object may be the same object stored in the drawable (though this is not guaranteed).
By default, this returns the full drawable bounds. Custom drawables may override this method to perform more precise invalidation.
Returns a Region representing the part of the Drawable that is completely transparent. This can be used to perform drawing operations, identifying which parts of the target will not change when rendering the Drawable. The default implementation returns null, indicating no transparent region; subclasses can optionally override this to return an actual Region if they want to supply this optimization information, but it is not required that they do so.
Inflate this Drawable from an XML resource optionally styled by a theme. This can't be called more than once for each Drawable. Note that framework may have called this once to create the Drawable instance from XML resource.
Whether this drawable requests projection. Indicates that the android.graphics.RenderNode this Drawable will draw into should be drawn immediately after the closest ancestor RenderNode containing a projection receiver.
Return the appropriate opacity value for two source opacities. If either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, that is returned; else, if either is TRANSPARENT, that is returned; else, OPAQUE is returned.
Specify the level for the drawable. This allows a drawable to vary its imagery based on a continuous controller, for example to show progress or volume level.
If the new level you are supplying causes the appearance of the Drawable to change, then it is responsible for calling invalidateSelf in order to have itself redrawn, and true will be returned from this function.
Specify a set of states for the drawable. These are use-case specific, so see the relevant documentation. As an example, the background for widgets like Button understand the following states: [android.R.attr#state_focused, android.R.attr#state_pressed].
If the new state you are supplying causes the appearance of the Drawable to change, then it is responsible for calling invalidateSelf in order to have itself redrawn, and true will be returned from this function.
Note: The Drawable holds a reference on to stateSet until a new state array is given to it, so you must not modify this array during that time.
Use the current Callback implementation to have this Drawable unscheduled. Does nothing if there is no Callback attached to the Drawable.
XML attributes
android:drawable
android:drawable
Reference to a drawable resource to use for the frame. If not given, the drawable must be defined by the first child tag.
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
Amount of time (in milliseconds) to display this frame.
May be an integer value, such as "100".
android:oneshot
android:oneshot
If true, the animation will only run a single time and then stop. If false (the default), it will continually run, restarting at the first frame after the last has finished.
May be a boolean value, such as "true" or "false".
android:variablePadding
android:variablePadding
If true, allows the drawable's padding to change based on the current state that is selected. If false, the padding will stay the same (based on the maximum padding of all the states). Enabling this feature requires that the owner of the drawable deal with performing layout when the state changes, which is often not supported.
May be a boolean value, such as "true" or "false".
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.
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.
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.
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Last updated 2024-06-18 UTC.
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