使用android animator 实现 弹跳的篮球效果

 //小球落下ValueAnimator downAnimator = ObjectAnimator.ofFloat(mShapeHolder, "y", startY , endY);downAnimator.setDuration(duration);downAnimator.setInterpolator(new AccelerateInterpolator());downAnimator.addUpdateListener(this);

   //小球上升ValueAnimator upAnimator = ObjectAnimator.ofFloat(mShapeHolder, "y", endY, startY);upAnimator.setDuration(duration);upAnimator.setInterpolator(new DecelerateInterpolator());upAnimator.addUpdateListener(this);

 // 1.设置小球的宽度变大ValueAnimator makeBallWide = ObjectAnimator.ofFloat(mShapeHolder, "width", mShapeHolder.getWidth(),mShapeHolder.getWidth() + BALLHEIGH/2);makeBallWide.setDuration(duration/4);//重复一次makeBallWide.setRepeatCount(1);//在重复另一次的时候回到原来的状态makeBallWide.setRepeatMode(ValueAnimator.REVERSE);makeBallWide.setInterpolator(new DecelerateInterpolator());// 2.在小球变扁的时候 需要让他居中ValueAnimator centerAnimator = ObjectAnimator.ofFloat(mShapeHolder, "x", mShapeHolder.getX(),mShapeHolder.getX() - BALLHEIGH/4);centerAnimator.setDuration(duration/4);centerAnimator.setRepeatCount(1);centerAnimator.setRepeatMode(ValueAnimator.REVERSE);centerAnimator.setInterpolator(new DecelerateInterpolator());centerAnimator.addUpdateListener(this);//3. 小球高度的变小ValueAnimator makeBallLow = ObjectAnimator.ofFloat(mShapeHolder, "height",mShapeHolder.getHeight(), mShapeHolder.getHeight() - BALLHEIGH/4);makeBallLow.setDuration(duration/4);makeBallLow.setRepeatCount(1);makeBallLow.setInterpolator(new DecelerateInterpolator());makeBallLow.setRepeatMode(ValueAnimator.REVERSE);//4.小球高度变化时y的居中ValueAnimator  yWhenBallisPlan = ObjectAnimator.ofFloat(mShapeHolder, "y", endY, endY + BALLHEIGH/3);yWhenBallisPlan.setDuration(duration/4);yWhenBallisPlan.setRepeatCount(1);yWhenBallisPlan.setInterpolator(new DecelerateInterpolator());yWhenBallisPlan.setRepeatMode(ValueAnimator.REVERSE);

public class MainActivity extends Activity {
        private ShapeHolder mShapeHolder;private final float BALLHEIGH = 100f;@SuppressWarnings("deprecation")@Overridepublic void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);setContentView(R.layout.bouncing_balls);int screenWidth = getWindowManager().getDefaultDisplay().getWidth();LinearLayout container = (LinearLayout) findViewById(R.id.container);mShapeHolder = addBall(screenWidth/2, 100);final MyAnimationView myAnimationView = new MyAnimationView(this);container.addView(myAnimationView);myAnimationView.post(new Runnable() {
        @Overridepublic void run() {
        myAnimationView.showBall();}});}public class MyAnimationView extends View implements AnimatorUpdateListener {
        public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();AnimatorSet animation = null;public MyAnimationView(Context context) {
        super(context);}public void showBall() {
        float startY = mShapeHolder.getY();float endY = getHeight() - BALLHEIGH;long duration = 1000;//小球落下ValueAnimator downAnimator = ObjectAnimator.ofFloat(mShapeHolder, "y", startY , endY);downAnimator.setDuration(duration);downAnimator.setInterpolator(new AccelerateInterpolator());//每次都需要添加这个监听刷新UI 否则不能看到动画downAnimator.addUpdateListener(this);// 1.设置小球的宽度变大ValueAnimator makeBallWide = ObjectAnimator.ofFloat(mShapeHolder, "width", mShapeHolder.getWidth(),mShapeHolder.getWidth() + BALLHEIGH/2);makeBallWide.setDuration(duration/4);//重复一次makeBallWide.setRepeatCount(1);//在重复另一次的时候回到原来的状态makeBallWide.setRepeatMode(ValueAnimator.REVERSE);makeBallWide.setInterpolator(new DecelerateInterpolator());// 2.在小球变扁的时候 需要让他居中ValueAnimator centerAnimator = ObjectAnimator.ofFloat(mShapeHolder, "x", mShapeHolder.getX(),mShapeHolder.getX() - BALLHEIGH/4);centerAnimator.setDuration(duration/4);centerAnimator.setRepeatCount(1);centerAnimator.setRepeatMode(ValueAnimator.REVERSE);centerAnimator.setInterpolator(new DecelerateInterpolator());centerAnimator.addUpdateListener(this);//3. 小球高度的变小ValueAnimator makeBallLow = ObjectAnimator.ofFloat(mShapeHolder, "height",mShapeHolder.getHeight(), mShapeHolder.getHeight() - BALLHEIGH/4);makeBallLow.setDuration(duration/4);makeBallLow.setRepeatCount(1);makeBallLow.setInterpolator(new DecelerateInterpolator());makeBallLow.setRepeatMode(ValueAnimator.REVERSE);//4.小球高度变化时y的居中ValueAnimator  yWhenBallisPlan = ObjectAnimator.ofFloat(mShapeHolder, "y", endY, endY + BALLHEIGH/3);yWhenBallisPlan.setDuration(duration/4);yWhenBallisPlan.setRepeatCount(1);yWhenBallisPlan.setInterpolator(new DecelerateInterpolator());yWhenBallisPlan.setRepeatMode(ValueAnimator.REVERSE);//小球上升ValueAnimator upAnimator = ObjectAnimator.ofFloat(mShapeHolder, "y", endY, startY);upAnimator.setDuration(duration);upAnimator.setInterpolator(new DecelerateInterpolator());upAnimator.addUpdateListener(this);final AnimatorSet animatorSet = new AnimatorSet();animatorSet.play(downAnimator).before(centerAnimator);animatorSet.playTogether(centerAnimator , makeBallWide ,makeBallLow, yWhenBallisPlan);animatorSet.play(upAnimator).after(centerAnimator);animatorSet.addListener(new AnimatorListenerAdapter() {
        @Overridepublic void onAnimationEnd(Animator animation) {
        animatorSet.start();super.onAnimationEnd(animation);}});animatorSet.start();}@Overrideprotected void onDraw(Canvas canvas) {
        canvas.save();canvas.translate(mShapeHolder.getX(), mShapeHolder.getY());mShapeHolder.getShape().draw(canvas);canvas.restore();}@Overridepublic void onAnimationUpdate(ValueAnimator arg0) {
        invalidate();}}private ShapeHolder addBall(float x, float y) {
        OvalShape circle = new OvalShape();circle.resize(BALLHEIGH, BALLHEIGH);ShapeDrawable drawable = new ShapeDrawable(circle);ShapeHolder shapeHolder = new ShapeHolder(drawable);shapeHolder.setX(x - BALLHEIGH/2);shapeHolder.setY(y - BALLHEIGH/2);int red = (int)(Math.random() * 255);int green = (int)(Math.random() * 255);int blue = (int)(Math.random() * 255);int color = 0xff000000 | red << 16 | green << 8 | blue;Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;RadialGradient gradient = new RadialGradient(37.5f, 12.5f,50f, color, darkColor, Shader.TileMode.CLAMP);paint.setShader(gradient);shapeHolder.setPaint(paint);return shapeHolder;}}