StarInterpolator.java

public class StarInterpolator implements Interpolator {

        public StarInterpolator() {
        }

        @SuppressWarnings({"UnusedDeclaration"})
        public StarInterpolator(Context context, AttributeSet attrs) {
        }

        private static float bounce(float t) {
            return t * t * 8.0f;
        }

        @Override
        public float getInterpolation(final float v) {
            //y = 0.65sin(6.28x - PI/2) + 0.65      (0 <= x < 0.748)
            //y = 8 * (1.1226x - 0.8526)^2 + 0.9    (0.748 <= x < 0.9644)
            //y = -8 * (1.1226x - 1.0435)^2 + 1.05  (0.9644 <= x <= 1)

            float x = v * 1.1226f;
            if (x < 0.7408f) {
                return (float) (0.65 * Math.sin(6.28 * v - Math.PI / 2) + 0.65);
            } else if (x < 0.9644f) {
                return bounce(x - 0.8526f) + 0.9f;
            } else {
                return -1 * bounce(x - 1.0435f) + 1.05f;
            }
        }
    }