An animation resource can define one of two types of animations:

Property Animation Creates an animation by modifying an object's property values over a set period of time with an Animator. View Animation

There are two types of animations that you can do with the view animation framework:

• Tween animation: Creates an animation by performing a series of transformations on a single image with an Animation
• Frame animation: or creates an animation by showing a sequence of images in order with an AnimationDrawable.

Property animation

An animation defined in XML that modifies properties of the target object, such as background color or alpha value, over a set amount of time.

file location: res/animator/filename.xml
The filename will be used as the resource ID.

compiled resource datatype: Resource pointer to a ValueAnimator, ObjectAnimator, or AnimatorSet.

resource reference: In Java-based or Kotlin code: R.animator.filename
In XML: @[package:]animator/filename

<set
  android:ordering=["together" | "sequentially"]>

<objectAnimator
        android:propertyName="string"
        android:duration="int"
        android:valueFrom="float | int | color"
        android:valueTo="float | int | color"
        android:startOffset="int"
        android:repeatCount="int"
        android:repeatMode=["restart" | "reverse"]
        android:valueType=["intType" | "floatType"]/>

<animator
        android:duration="int"
        android:valueFrom="float | int | color"
        android:valueTo="float | int | color"
        android:startOffset="int"
        android:repeatCount="int"
        android:repeatMode=["restart" | "reverse"]
        android:valueType=["intType" | "floatType"]/>

<set>
        ...
    </set>
</set>

The file must have a single root element: either <set>, <objectAnimator>, or <valueAnimator>. You can group animation elements together inside the <set> element, including other <set> elements.

You can specify nested <set> tags to further group animations together. Each <set> can define its own ordering attribute.

attributes:

<objectAnimator> Animates a specific property of an object over a specific amount of time. Represents an ObjectAnimator.

attributes:

android:propertyName String. Required. The object's property to animate, referenced by its name. For example you can specify "alpha" or "backgroundColor" for a View object. The objectAnimator element does not expose a target attribute, however, so you cannot set the object to animate in the XML declaration. You have to inflate your animation XML resource by calling loadAnimator() and call setTarget() to set the target object that contains this property.

android:valueTo float, int, or color. Required. The value where the animated property ends. Colors are represented as six digit hexadecimal numbers (for example, #333333).

android:valueFrom float, int, or color. The value where the animated property starts. If not specified, the animation starts at the value obtained by the property's get method. Colors are represented as six digit hexadecimal numbers (for example, #333333).

android:duration int. The time in milliseconds of the animation. 300 milliseconds is the default.

android:startOffset int. The amount of milliseconds the animation delays after start() is called.

android:repeatCount int. How many times to repeat an animation. Set to "-1" to infinitely repeat or to a positive integer. For example, a value of "1" means that the animation is repeated once after the initial run of the animation, so the animation plays a total of two times. The default value is "0", which means no repetition.

android:repeatMode int. How an animation behaves when it reaches the end of the animation. android:repeatCount must be set to a positive integer or "-1" for this attribute to have an effect. Set to "reverse" to have the animation reverse direction with each iteration or "restart" to have the animation loop from the beginning each time.

<animator> Performs an animation over a specified amount of time. Represents a ValueAnimator.

attributes:

android:valueTo float, int, or color. Required. The value where the animation ends. Colors are represented as six digit hexadecimal numbers (for example, #333333).

android:valueFrom float, int, or color. Required. The value where the animation starts. Colors are represented as six digit hexadecimal numbers (for example, #333333).

android:duration int. The time in milliseconds of the animation. 300ms is the default.

android:startOffset int. The amount of milliseconds the animation delays after start() is called.

android:repeatCount int. How many times to repeat an animation. Set to "-1" to infinitely repeat or to a positive integer. For example, a value of "1" means that the animation is repeated once after the initial run of the animation, so the animation plays a total of two times. The default value is "0", which means no repetition.

android:repeatMode int. How an animation behaves when it reaches the end of the animation. android:repeatCount must be set to a positive integer or "-1" for this attribute to have an effect. Set to "reverse" to have the animation reverse direction with each iteration or "restart" to have the animation loop from the beginning each time.

<set android:ordering="sequentially">
    <set>
        <objectAnimator
            android:propertyName="x"
            android:duration="500"
            android:valueTo="400"
            android:valueType="intType"/>
        <objectAnimator
            android:propertyName="y"
            android:duration="500"
            android:valueTo="300"
            android:valueType="intType"/>
    </set>
    <objectAnimator
        android:propertyName="alpha"
        android:duration="500"
        android:valueTo="1f"/>
</set>

In order to run this animation, you must inflate the XML resources in your code to an AnimatorSet object, and then set the target objects for all of the animations before starting the animation set. Calling setTarget() sets a single target object for all children of the AnimatorSet as a convenience. The following code shows how to do this:

val set: AnimatorSet = AnimatorInflater.loadAnimator(myContext, R.animator.property_animator)
    .apply {
        setTarget(myObject)
        start()
    }

• Property Animation
• API Demos for examples on how to use the property animation system.

View animation

The view animation framework supports both tween and frame by frame animations, which can both be declared in XML. The following sections describe how to use both methods.

Tween animation

An animation defined in XML that performs transitions such as rotating, fading, moving, and stretching on a graphic.

file location: res/anim/filename.xml
The filename will be used as the resource ID.

compiled resource datatype: Resource pointer to an Animation.

resource reference: In Java: R.anim.filename
In XML: @[package:]anim/filename

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@[package:]anim/interpolator_resource"
    android:shareInterpolator=["true" | "false"] >
    <alpha
        android:fromAlpha="float"
        android:toAlpha="float" />
    <scale
        android:fromXScale="float"
        android:toXScale="float"
        android:fromYScale="float"
        android:toYScale="float"
        android:pivotX="float"
        android:pivotY="float" />
    <translate
        android:fromXDelta="float"
        android:toXDelta="float"
        android:fromYDelta="float"
        android:toYDelta="float" />
    <rotate
        android:fromDegrees="float"
        android:toDegrees="float"
        android:pivotX="float"
        android:pivotY="float" />
    <set>
        ...
    </set>
</set>

The file must have a single root element: either an <alpha>, <scale>, <translate>, <rotate>, or <set> element that holds a group (or groups) of other animation elements (even nested <set> elements).

attributes:

attributes:

For more attributes supported by <alpha>, see the Animation class reference (of which, all XML attributes are inherited by this element).

attributes:

For more attributes supported by <scale>, see the Animation class reference (of which, all XML attributes are inherited by this element).

attributes:

For more attributes supported by <translate>, see the Animation class reference (of which, all XML attributes are inherited by this element).

attributes:

For more attributes supported by <rotate>, see the Animation class reference (of which, all XML attributes are inherited by this element).

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:shareInterpolator="false">
    <scale
        android:interpolator="@android:anim/accelerate_decelerate_interpolator"
        android:fromXScale="1.0"
        android:toXScale="1.4"
        android:fromYScale="1.0"
        android:toYScale="0.6"
        android:pivotX="50%"
        android:pivotY="50%"
        android:fillAfter="false"
        android:duration="700" />
    <set
        android:interpolator="@android:anim/accelerate_interpolator"
        android:startOffset="700">
        <scale
            android:fromXScale="1.4"
            android:toXScale="0.0"
            android:fromYScale="0.6"
            android:toYScale="0.0"
            android:pivotX="50%"
            android:pivotY="50%"
            android:duration="400" />
        <rotate
            android:fromDegrees="0"
            android:toDegrees="-45"
            android:toYScale="0.0"
            android:pivotX="50%"
            android:pivotY="50%"
            android:duration="400" />
    </set>
</set>

This application code will apply the animation to an ImageView and start the animation:

val image: ImageView = findViewById(R.id.image)
val hyperspaceJump: Animation = AnimationUtils.loadAnimation(this, R.anim.hyperspace_jump)
image.startAnimation(hyperspaceJump)

• 2D Graphics: Tween Animation

Interpolators

An interpolator is an animation modifier defined in XML that affects the rate of change in an animation. This allows your existing animation effects to be accelerated, decelerated, repeated, bounced, etc.

An interpolator is applied to an animation element with the android:interpolator attribute, the value of which is a reference to an interpolator resource.

All interpolators available in Android are subclasses of the Interpolator class. For each interpolator class, Android includes a public resource you can reference in order to apply the interpolator to an animation using the android:interpolator attribute. The following table specifies the resource to use for each interpolator:

Here's how you can apply one of these with the android:interpolator attribute:

<set android:interpolator="@android:anim/accelerate_interpolator">
    ...
</set>

Custom interpolators

If you're not satisfied with the interpolators provided by the platform (listed in the table above), you can create a custom interpolator resource with modified attributes. For example, you can adjust the rate of acceleration for the AnticipateInterpolator, or adjust the number of cycles for the CycleInterpolator. In order to do so, you need to create your own interpolator resource in an XML file.

file location: res/anim/filename.xml
The filename will be used as the resource ID.

compiled resource datatype: Resource pointer to the corresponding interpolator object.

resource reference: In XML: @[package:]anim/filename

<?xml version="1.0" encoding="utf-8"?>
<InterpolatorName xmlns:android="http://schemas.android.com/apk/res/android"
    android:attribute_name="value"
    />

If you don't apply any attributes, then your interpolator will function exactly the same as those provided by the platform (listed in the table above).

No attributes.

attributes:

attributes:

attributes:

No attributes

attributes:

attributes:

No attributes.

attributes:

XML file saved at res/anim/my_overshoot_interpolator.xml:

<?xml version="1.0" encoding="utf-8"?>
<overshootInterpolator xmlns:android="http://schemas.android.com/apk/res/android"
    android:tension="7.0"
    />

This animation XML will apply the interpolator:

<scale xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@anim/my_overshoot_interpolator"
    android:fromXScale="1.0"
    android:toXScale="3.0"
    android:fromYScale="1.0"
    android:toYScale="3.0"
    android:pivotX="50%"
    android:pivotY="50%"
    android:duration="700" />

Frame animation

An animation defined in XML that shows a sequence of images in order (like a film).

file location: res/drawable/filename.xml
The filename will be used as the resource ID.

compiled resource datatype: Resource pointer to an AnimationDrawable.

resource reference: In Java: R.drawable.filename
In XML: @[package:]drawable.filename

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:oneshot=["true" | "false"] >
    <item
        android:drawable="@[package:]drawable/drawable_resource_name"
        android:duration="integer" />
</animation-list>

elements: <animation-list> Required. This must be the root element. Contains one or more <item> elements.

attributes:

attributes:

android:drawable Drawable resource. The drawable to use for this frame. android:duration Integer. The duration to show this frame, in milliseconds.

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:oneshot="false">
    <item android:drawable="@drawable/rocket_thrust1" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust2" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust3" android:duration="200" />
</animation-list>

This application code will set the animation as the background for a View, then play the animation:

val rocketImage: ImageView = findViewById(R.id.rocket_image)
rocketImage.setBackgroundResource(R.drawable.rocket_thrust)

val rocketAnimation = rocketImage.background
if (rocketAnimation is Animatable) {
    rocketAnimation.start()
}

see also:

• 2D Graphics: Frame Animation