public class FavorLayout extends RelativeLayout{

private Random random = new Random();//用于實(shí)現(xiàn)隨機(jī)功能

 private int dHeight;//愛(ài)心的高度
 private int dWidth;//愛(ài)心的寬度
private int mHeight;//FavorLayout的高度
 private int mWidth;//FavorLayout的寬度
public FavorLayout(Context context) {
 super(context);
 }
public FavorLayout(Context context, AttributeSet attrs) {

 super(context, attrs);
 //為了顯示區(qū)域,我設(shè)置了一個(gè)背景顏色,隨意
 setBackgroundColor(getResources().getColor(R.color.bg));
//init里做一些初始化變量的操作
 init();
}


//重寫(xiě)onMeasure 獲取控件寬高
@Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 //注意!! 獲取本身的寬高 需要在測(cè)量之后才有寬高
 mWidth = getMeasuredWidth();
 mHeight = getMeasuredHeight();
 }

}
//定義完畢后我們來(lái)實(shí)現(xiàn)底部,水平居中:

//定義一個(gè)LayoutParams 用它來(lái)控制子view的位置
 private LayoutParams lp;

 //底部 并且 水平居中
 lp = new LayoutParams(dWidth, dHeight);
 lp.addRule(CENTER_HORIZONTAL, TRUE); //這里的TRUE 要注意 不是true
 lp.addRule(ALIGN_PARENT_BOTTOM, TRUE);
 //好了,之后只要給子view設(shè)置LayoutParams就可以實(shí)現(xiàn)了

//首先定義 3個(gè)代表不同愛(ài)心的drawable,以及他們的和drawables
 private Drawable red ;
 private Drawable yellow ;
 private Drawable blue ;
 private Drawable[] drawables ;

 //接下去我們初始化:
 //初始化顯示的圖片
 drawables = new Drawable[3];
 red = getResources().getDrawable(R.mipmap.red);
 yellow = getResources().getDrawable(R.mipmap.yellow);
 blue = getResources().getDrawable(R.mipmap.blue);
 //賦值給drawables
 drawables[0]=red;
 drawables[1]=yellow;
 drawables[2]=blue;

drawables[random.nextInt(3)]//表示0-2的隨機(jī)數(shù),注意,3是取不到的,是個(gè)開(kāi)區(qū)間

//我封裝了一個(gè)方法 利用ObjectAnimator AnimatorSet來(lái)實(shí)現(xiàn) alpha以及x,y軸的縮放功能
//target就是愛(ài)心
private AnimatorSet getEnterAnimtor(final View target) {

 ObjectAnimator alpha = ObjectAnimator.ofFloat(target,View.ALPHA, 0.2f, 1f);
 ObjectAnimator scaleX = ObjectAnimator.ofFloat(target,View.SCALE_X, 0.2f, 1f);
 ObjectAnimator scaleY = ObjectAnimator.ofFloat(target,View.SCALE_Y, 0.2f, 1f);
 AnimatorSet enter = new AnimatorSet();
 enter.setDuration(500);
 enter.setInterpolator(new LinearInterpolator());
 enter.playTogether(alpha,scaleX, scaleY);
 enter.setTarget(target);
 return enter;
 }

mBtnStartAnim.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 mFavorLayout.addFavor();
 }
 });

public void addFavor() {

 ImageView imageView = new ImageView(getContext());
 //隨機(jī)選一個(gè)
 imageView.setImageDrawable(drawables[random.nextInt(3)]);
 // 設(shè)置底部 水平居中
 imageView.setLayoutParams(lp);

 addView(imageView);
 Log.v(TAG, "add后子view數(shù):"+getChildCount());

 Animator set = getEnterAnimtor(imageView);
 set.start();

}

//我們自定義一個(gè)BezierEvaluator 實(shí)現(xiàn) TypeEvaluator
//由于我們view的移動(dòng)需要控制x y 所以就傳入PointF 作為參數(shù),是不是感覺(jué)完全契合??
public class BezierEvaluator implements TypeEvaluator<PointF> {


 private PointF pointF1;//途徑的兩個(gè)點(diǎn) 
 private PointF pointF2;
 public BezierEvaluator(PointF pointF1,PointF pointF2){
 this.pointF1 = pointF1;
 this.pointF2 = pointF2;
 }
 @Override
 public PointF evaluate(float time, PointF startValue,
  PointF endValue) {

 float timeLeft = 1.0f - time;
 PointF point = new PointF();//結(jié)果

 PointF point0 = (PointF)startValue;//起點(diǎn)

 PointF point3 = (PointF)endValue;//終點(diǎn)
 //代入公式 
 point.x = timeLeft * timeLeft * timeLeft * (point0.x)
 + 3 * timeLeft * timeLeft * time * (pointF1.x)
 + 3 * timeLeft * time * time * (pointF2.x)
 + time * time * time * (point3.x);

 point.y = timeLeft * timeLeft * timeLeft * (point0.y)
 + 3 * timeLeft * timeLeft * time * (pointF1.y)
 + 3 * timeLeft * time * time * (pointF2.y)
 + time * time * time * (point3.y);
 return point;
 }
}

private ValueAnimator getBezierValueAnimator(View target) {

 //初始化一個(gè)BezierEvaluator
 BezierEvaluator evaluator = new BezierEvaluator(getPointF(2),getPointF(1));

 //這里最好畫(huà)個(gè)圖 理解一下 傳入了起點(diǎn) 和 終點(diǎn)
 ValueAnimator animator = ValueAnimator.ofObject(evaluator,new PointF((mWidth-dWidth)/2,mHeight-dHeight),new PointF(random.nextInt(getWidth()),0));//隨機(jī)
 animator.addUpdateListener(new BezierListenr(target));
 animator.setTarget(target);
 animator.setDuration(3000);
 return animator;
 }

//這里涉及到另外一個(gè)方法:getPointF(),這個(gè)是我用來(lái)獲取途徑的兩個(gè)點(diǎn)
// 這里的取值可以隨意調(diào)整,調(diào)整到你希望的樣子就好
/**
 * 獲取中間的兩個(gè) 點(diǎn)
 * @param scale
 */
 private PointF getPointF(int scale) {

 PointF pointF = new PointF();
 pointF.x = random.nextInt((mWidth - 100));//減去100 是為了控制 x軸活動(dòng)范圍,看效果 隨意~~
 //再Y軸上 為了確保第二個(gè)點(diǎn) 在第一個(gè)點(diǎn)之上,我把Y分成了上下兩半 這樣動(dòng)畫(huà)效果好一些 也可以用其他方法
 pointF.y = random.nextInt((mHeight - 100))/scale;
 return pointF;
 }

private class BezierListenr implements ValueAnimator.AnimatorUpdateListener {

 private View target;

 public BezierListenr(View target) {
 this.target = target;
 }
 @Override
 public void onAnimationUpdate(ValueAnimator animation) {
 //這里獲取到貝塞爾曲線計(jì)算出來(lái)的的x y值 賦值給view 這樣就能讓愛(ài)心隨著曲線走啦
 PointF pointF = (PointF) animation.getAnimatedValue();
 target.setX(pointF.x);
 target.setY(pointF.y);
 // 這里偷個(gè)懶,順便做一個(gè)alpha動(dòng)畫(huà),這樣alpha漸變也完成啦
 target.setAlpha(1-animation.getAnimatedFraction());
 }
 }

public void addFavor() {

 ImageView imageView = new ImageView(getContext());
 //隨機(jī)選一個(gè)
 imageView.setImageDrawable(drawables[random.nextInt(3)]);
 imageView.setLayoutParams(lp);
 addView(imageView);
 Log.v(TAG, "add后子view數(shù):"+getChildCount());
 getBezierValueAnimator(imageView).start();
 }

// 我為了實(shí)現(xiàn) 變速效果 挑選了幾種插補(bǔ)器
private Interpolator line = new LinearInterpolator();//線性
 private Interpolator acc = new AccelerateInterpolator();//加速
 private Interpolator dce = new DecelerateInterpolator();//減速
 private Interpolator accdec = new AccelerateDecelerateInterpolator();//先加速后減速
 // 在init中初始化
 private Interpolator[] interpolators ;

// 最終 init方法長(zhǎng)這樣:
private void init() {

 //初始化顯示的圖片
 drawables = new Drawable[3];
 red = getResources().getDrawable(R.mipmap.red);
 yellow = getResources().getDrawable(R.mipmap.yellow);
 blue = getResources().getDrawable(R.mipmap.blue);

 drawables[0]=red;
 drawables[1]=yellow;
 drawables[2]=blue;
 //獲取圖的寬高 用于后面的計(jì)算
 //注意 我這里3張圖片的大小都是一樣的,所以我只取了一個(gè)
 dHeight = red.getIntrinsicHeight();
 dWidth = red.getIntrinsicWidth();

 //底部 并且 水平居中
 lp = new LayoutParams(dWidth, dHeight);
 lp.addRule(CENTER_HORIZONTAL, TRUE);//這里的TRUE 要注意 不是true
 lp.addRule(ALIGN_PARENT_BOTTOM, TRUE);

 // 初始化插補(bǔ)器
 interpolators = new Interpolator[4];
 interpolators[0] = line;
 interpolators[1] = acc;
 interpolators[2] = dce;
 interpolators[3] = accdec;

 }

private Animator getAnimator(View target){
 AnimatorSet set = getEnterAnimtor(target);

 ValueAnimator bezierValueAnimator = getBezierValueAnimator(target);

 AnimatorSet finalSet = new AnimatorSet();
 finalSet.playSequentially(set);
 finalSet.playSequentially(set, bezierValueAnimator);
 finalSet.setInterpolator(interpolators[random.nextInt(4)]);//實(shí)現(xiàn)隨機(jī)變速
 finalSet.setTarget(target);
 return finalSet;
 }

public void addFavor() {

 ImageView imageView = new ImageView(getContext());
 //隨機(jī)選一個(gè)
 imageView.setImageDrawable(drawables[random.nextInt(3)]);
 imageView.setLayoutParams(lp);

 addView(imageView);
 Log.v(TAG, "add后子view數(shù):"+getChildCount());

 Animator set = getAnimator(imageView);
 set.addListener(new AnimEndListener(imageView));
 set.start();

 }

private class AnimEndListener extends AnimatorListenerAdapter {
 private View target;

 public AnimEndListener(View target) {
 this.target = target;
 }
 @Override
 public void onAnimationEnd(Animator animation) {
 super.onAnimationEnd(animation);
 //因?yàn)椴煌５腶dd 導(dǎo)致子view數(shù)量只增不減,所以在view動(dòng)畫(huà)結(jié)束后remove掉
 removeView((target));
 Log.v(TAG, "removeView后子view數(shù):"+getChildCount());
 }
 }