@SuppressWarnings("unused")
    void setRotation(float rotation) {
        mRotation = rotation;
        invalidateSelf();
    }
Set the colors used in the progress animation from color resources.
The first color will also be the color of the bar that grows in response
to a user swipe gesture.

@param colors
common/src/main/java/com/sxjs/common/widget/pulltorefresh/header/MaterialProgressDrawable.java