主要运用Drawable动画进行绘制。

public class ThreeBallsLoadingDrawable extends Drawable implements Animatable {
准备三只画笔，分别绘制三个圆形图案
private Paint mLeftPaint,mMiddlePaint,mRightPaint;
    @Override
    public void draw(Canvas canvas) {
        canvas.save();
        canvas.translate(translateX,0);
        canvas.drawCircle(RADIUS,mHeight/2,RADIUS,mLeftPaint);
        canvas.restore();
        canvas.save();
        canvas.drawCircle(mWidth/2,mHeight/2,RADIUS,mMiddlePaint);
        canvas.restore();
        canvas.save();
        canvas.translate(-translateX,0);
        canvas.drawCircle(mWidth-RADIUS,mHeight/2,RADIUS,mRightPaint);
        canvas.restore();
进行动画部分代码编写，主要运用ValueAnimator
分析动画，左侧圆形图案，向右平移到中间，然后变换颜色，在反向平移到原来位置。所以我们动画分为两部分，向内平移和向外平移。向内平移动画结束，变化圆形图案颜色（变化策略在上方）
     * 向内平移
    private void innerMove() {
        final ValueAnimator translateXInnerAnimation = ValueAnimator.ofFloat(0,170);
        translateXInnerAnimation.setDuration(ANIMATION_DURATION);
        translateXInnerAnimation.setInterpolator(new AccelerateInterpolator());
        translateXInnerAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                translateX = (float) translateXInnerAnimation.getAnimatedValue();
                invalidateSelf();
        translateXInnerAnimation.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                super.onAnimationEnd(animation);
                //变换颜色
                exchangeColor();
                expendMove();
        translateXInnerAnimation.start();
     * 向外平移
    private void expendMove(){
        final ValueAnimator translateXExpendAnimation = ValueAnimator.ofFloat(170,0);
        translateXExpendAnimation.setDuration(ANIMATION_DURATION);
        translateXExpendAnimation.setInterpolator(new DecelerateInterpolator());
        translateXExpendAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                translateX = (float) translateXExpendAnimation.getAnimatedValue();
                invalidateSelf();
        translateXExpendAnimation.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                super.onAnimationEnd(animation);
                innerMove();
        translateXExpendAnimation.start();
     * 变换颜色方法
    private void exchangeColor(){
        int mLeftPaintColor = mLeftPaint.getColor();
        int mRightPaintColor = mRightPaint.getColor();
        int mMiddlePaintColor = mMiddlePaint.getColor();
        mLeftPaint.setColor(mRightPaintColor);
        mRightPaint.setColor(mMiddlePaintColor);
        mMiddlePaint.setColor(mLeftPaintColor);
在ImageView中设置drawable即可
ThreeBallsLoadingDrawable threeBallsLoadingDrawable  = new ThreeBallsLoadingDrawable();
imageView.setImageDrawable(threeBallsLoadingDrawable);
threeBallsLoadingDrawable.start();
GitHub地址
有用记得点颗小星星
往期文章地址
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