<?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/ic_loading_0" android:duration="100"/>
    <item android:drawable="@drawable/ic_loading_1" android:duration="100"/>
    <item android:drawable="@drawable/ic_loading_2" android:duration="100"/> 
    <item android:drawable="@drawable/ic_loading_3" android:duration="100"/> 
    <item android:drawable="@drawable/ic_loading_4" android:duration="100"/> 
    <item android:drawable="@drawable/ic_loading_5" android:duration="100"/> 
    <item android:drawable="@drawable/ic_loading_6" android:duration="100"/>
    <item android:drawable="@drawable/ic_loading_7" android:duration="100"/>
</animation-list>

<?xml version="1.0" encoding="utf-8"?> 
<rotate xmlns:android="http://schemas.android.com/apk/res/android" android:duration="1000"
        android:fillAfter="true"
        android:fromDegrees="0"
        android:pivotX="50%" 
        android:pivotY="50%"
        android:repeatCount="1"
        android:toDegrees="180">
</rotate>

<?xml version="1.0" encoding="utf-8"?>
<alpha xmlns:android="http://schemas.android.com/apk/res/android" android:duration="1000"
       android:fromAlpha="1.0"
       android:toAlpha="0.5">
</alpha>

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android" android:duration="1000"
           android:fromXDelta="0"
           android:fromYDelta="0"
           android:toXDelta="100%"
           android:toYDelta="100%">
</translate>

<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android" android:duration="1000"
       android:fromXScale="1.0"
       android:fromYScale="1.0"
       android:toXScale="1.2"
       android:toYScale="1.2"
       android:pivotX="50%"
       android:pivotY="50%">
</scale>

ValueAnimator.ofFloat(0f, 1f)

new ObjectAnimator().addListener(new AnimatorListenerAdapter() {
    @Override
    public void onAnimationCancel(Animator animation) {
        super.onAnimationCancel(animation);
    }

    @Override
    public void onAnimationEnd(Animator animation) {
        super.onAnimationEnd(animation);
    }

    @Override
    public void onAnimationRepeat(Animator animation) {
        super.onAnimationRepeat(animation);
    }

    @Override
    public void onAnimationStart(Animator animation) {
        super.onAnimationStart(animation);
    }

    @Override
    public void onAnimationPause(Animator animation) {
        super.onAnimationPause(animation);
    }

    @Override
    public void onAnimationResume(Animator animation) {
        super.onAnimationResume(animation);
    }
});

public interface TypeEvaluator<T> {

    /**
     * This function returns the result of linearly interpolating the start and end values, with
     * <code>fraction</code> representing the proportion between the start and end values. The
     * calculation is a simple parametric calculation: <code>result = x0 + t * (x1 - x0)</code>,
     * where <code>x0</code> is <code>startValue</code>, <code>x1</code> is <code>endValue</code>,
     * and <code>t</code> is <code>fraction</code>.
     *
     * @param fraction   The fraction from the starting to the ending values
     * @param startValue The start value.
     * @param endValue   The end value.
     * @return A linear interpolation between the start and end values, given the
     *         <code>fraction</code> parameter.
     */
    public T evaluate(float fraction, T startValue, T endValue);

}

ObjectAnimator.ofObject(target, propertyName, evaluator, values);

public interface Interpolator extends TimeInterpolator {
    // A new interface, TimeInterpolator, was introduced for the new android.animation
    // package. This older Interpolator interface extends TimeInterpolator so that users of
    // the new Animator-based animations can use either the old Interpolator implementations or
    // new classes that implement TimeInterpolator directly.
}

public abstract void setInterpolator(TimeInterpolator value);