QQ上發送么么噠時候，彈出彈跳錶情，是如何實現的？

AnimatorSet set1 = LuoChaJump(PointList.get(0).getX(),PointList.get(0).getY(),
PointList.get(1).getX(),PointList.get(1).getY());

AnimatorSet set2 = PinTiao(PointList.get(1).getX(),PointList.get(1).getY(),
PointList.get(1).getX()+50,PointList.get(1).getY(),100);

AnimatorSet set3 = PinTiao(PointList.get(1).getX()+50,PointList.get(1).getY(),
PointList.get(1).getX()+100,PointList.get(1).getY(),50);

AnimatorSet set4 = LuoChaJump(PointList.get(1).getX()+100,PointList.get(1).getY(),
PointList.get(2).getX(),PointList.get(2).getY());

AnimatorSet set5 = PinTiao(PointList.get(2).getX(),PointList.get(2).getY(),
PointList.get(2).getX()-50,PointList.get(2).getY(),100);

AnimatorSet set6 = PinTiao(PointList.get(2).getX()-50,PointList.get(2).getY(),
PointList.get(2).getX()-100,PointList.get(2).getY(),50);

AnimatorSet set7 = FinishDown(PointList.get(2).getX()-100,PointList.get(2).getY());

AnimatorSet set = new AnimatorSet();
set.playSequentially(anim,set1,set2,set3,set4,set5,set6,set7);
set.start();
}

public Animator FirstDown(float x1,float y1,float y2){
Point startPoint = new Point(x1, y1);
Point endPoint = new Point(x1, y2);
ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint);
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim.setInterpolator(new BounceInterpolator());
anim.setDuration(2500);
return anim;
}

public AnimatorSet LuoChaJump(float x1,float y1,float x2,float y2){
float dx = (x2-x1)/3+x1;
Point startPoint = new Point(x1, y1);
Point endPoint = new Point(dx, y1-500);
ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint);
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim.setInterpolator(new DecelerateInterpolator());
anim.setDuration(1000);

Point startPoint2 = new Point(dx, y1-500);
Point endPoint2 = new Point(x2, y2);
ValueAnimator anim2 = ValueAnimator.ofObject(new PointEvaluator(), startPoint2, endPoint2);
anim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim2.setInterpolator(new AccelerateInterpolator());
anim2.setDuration(1500);

AnimatorSet set = new AnimatorSet();
set.play(anim2).after(anim);
return set;

}

public AnimatorSet PinTiao(float x1,float y1,float x2,float y2,int dy){
float dx = (x2-x1)/2+x1;
Point startPoint = new Point(x1, y1);
Point endPoint = new Point(dx, y1-dy);
ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint);
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim.setInterpolator(new DecelerateInterpolator());
anim.setDuration(300);

Point startPoint2 = new Point(dx, y1-dy);
Point endPoint2 = new Point(x2, y2);
ValueAnimator anim2 = ValueAnimator.ofObject(new PointEvaluator(), startPoint2, endPoint2);
anim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim2.setInterpolator(new AccelerateInterpolator());
anim2.setDuration(250);

AnimatorSet set = new AnimatorSet();
set.play(anim2).after(anim);
return set;
}

public AnimatorSet FinishDown(float x1,float y1){
Point startPoint = new Point(x1, y1);
Point endPoint = new Point(x1, y1-100);
ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint);
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim.setInterpolator(new DecelerateInterpolator());
anim.setDuration(250);

Point startPoint2 = new Point(x1, y1-100);
Point endPoint2 = new Point(x1, MyUtils.getScreenHeight(mContext)+100);
ValueAnimator anim2 = ValueAnimator.ofObject(new PointEvaluator(), startPoint2, endPoint2);
anim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentPoint = (Point) animation.getAnimatedValue();
invalidate();
}
});
anim2.setInterpolator(new AccelerateInterpolator());
anim2.setDuration(1500);

ObjectAnimator animation2 = ObjectAnimator.ofFloat(this,"translationY",y,y-300);
animation2.setDuration(500);
animation2.setInterpolator(new DecelerateInterpolator());

ObjectAnimator animation3 = ObjectAnimator.ofFloat(this,"translationX",x+200,x+400);
animation3.setDuration(500);
animation3.setInterpolator(new LinearInterpolator());

ObjectAnimator animation4 = ObjectAnimator.ofFloat(this,"translationY",y-300,y);
animation4.setDuration(500);
animation4.setInterpolator(new AccelerateInterpolator());

ObjectAnimator animation5 = ObjectAnimator.ofFloat(this,"translationX",x+400,x+500);
animation5.setDuration(300);
animation5.setInterpolator(new LinearInterpolator());

ObjectAnimator animation6 = ObjectAnimator.ofFloat(this,"translationY",y,y-150);
animation6.setDuration(300);
animation6.setInterpolator(new DecelerateInterpolator());

ObjectAnimator animation7 = ObjectAnimator.ofFloat(this,"translationX",x+500,x+600);
animation7.setDuration(300);
animation7.setInterpolator(new LinearInterpolator());

ObjectAnimator animation8 = ObjectAnimator.ofFloat(this,"translationY",y-150,y);
animation8.setDuration(300);
animation8.setInterpolator(new AccelerateInterpolator());

ObjectAnimator animation9 = ObjectAnimator.ofFloat(this,"translationX",x+600,x+640);
animation9.setDuration(200);
animation9.setInterpolator(new LinearInterpolator());

ObjectAnimator animation10 = ObjectAnimator.ofFloat(this,"translationY",y,y-100);
animation10.setDuration(200);
animation10.setInterpolator(new DecelerateInterpolator());

ObjectAnimator animation11 = ObjectAnimator.ofFloat(this,"translationX",x+640,x+680);
animation11.setDuration(200);
animation11.setInterpolator(new LinearInterpolator());

ObjectAnimator animation12 = ObjectAnimator.ofFloat(this,"translationY",y-100,y);
animation12.setDuration(200);
animation12.setInterpolator(new AccelerateInterpolator());

AnimatorSet set1 = new AnimatorSet();
set1.play(animation1).with(animation2);

AnimatorSet set2 = new AnimatorSet();
set2.play(animation3).with(animation4);

AnimatorSet set3 = new AnimatorSet();
set3.play(animation5).with(animation6);

AnimatorSet set4 = new AnimatorSet();
set4.play(animation7).with(animation8);

AnimatorSet set5 = new AnimatorSet();
set5.play(animation9).with(animation10);

AnimatorSet set6 = new AnimatorSet();
set6.play(animation11).with(animation12);

• 遇到的麻煩

1. view不斷重畫會很卡，用surfaceview替代
2. 動畫的顯示可能會很長，這裡用到了scrollview當做父容器
3. 禁止scrollview滑動
4. surfaceview直接添加的話高度為零,需要放到一個LinearLayout當中
5. surfaceview的高度不應該是固定值
6. 因為可利用數據只是屏幕內能看到的內容，所以需要不斷更新數據，加入新的坐標點。這裡偷下懶，對象引用傳遞就好了。

• 大功告成！

http://upload-images.jianshu.io/upload_images/2482523-2918b8bf00d4a185.gif

以上です。

知乎首答就這樣沒了，:-(

iOS 上直接用 UIDynamicAnimator 就好了，為什麼 要做高中物理題