public void applyTransformation(float interpolatedTime, Transformation t) {
                // shrink back down and complete a full rotation before starting other circles
                // Rotation goes between [0..1].
                float targetRotation = (float) (Math.floor(ring.getStartingRotation()
                        / MAX_PROGRESS_ARC) + 1f);
                final float startTrim = ring.getStartingStartTrim()
                        + (ring.getStartingEndTrim() - ring.getStartingStartTrim())
                        * interpolatedTime;
                ring.setStartTrim(startTrim);
                final float rotation = ring.getStartingRotation()
                        + ((targetRotation - ring.getStartingRotation()) * interpolatedTime);
                ring.setRotation(rotation);
                ring.setArrowScale(1 - interpolatedTime);
            }
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
library/src/main/java/com/baoyz/widget/MaterialDrawable.java