BallPulseIndicator.java 文件源码

@Override
public ArrayList<ValueAnimator> onCreateAnimators() {
    ArrayList<ValueAnimator> animators = new ArrayList<>();
    int[] delays = new int[]{120, 240, 360};
    for (int i = 0; i < 3; i++) {
        final int index = i;

        ValueAnimator scaleAnim = ValueAnimator.ofFloat(1, 0.3f, 1);

        scaleAnim.setDuration(750);
        scaleAnim.setRepeatCount(-1);
        scaleAnim.setStartDelay(delays[i]);

        addUpdateListener(scaleAnim, animation -> {
            scaleFloats[index] = (float) animation.getAnimatedValue();
            postInvalidate();
        });
        animators.add(scaleAnim);
    }
    return animators;
}