分享一个很炫的Periscope点赞效果

上次见到同学了做了一个非常炫的点赞动画，见猎心喜，查了查资料才知道是Periscope点赞效果，网上大神已经对此写过很容易集成的库了，今天迫不及待的想跟大家分享一下

分享大神git库地址

Periscope点赞效果

先看看大神做的效果吧

这里是项目结构

periscopelayout.java是动画所在布局，BezierEvaluator是贝塞尔计算器

整个项目可以看到这个动画的流程，
1.自定义动画布局
2.初始化爱心的缩放动画
3.爱心的随机出现，插值器的随机出现
4.爱心在滑动过程中透明度的渐变
5.滑动曲线的实现，实现贝塞尔曲线效果

PeriscopeLayout.java

package me.yifeiyuan.periscopelayout;import android.animation.Animator;import android.animation.AnimatorListenerAdapter;import android.animation.AnimatorSet;import android.animation.ObjectAnimator;import android.animation.ValueAnimator;import android.annotation.TargetApi;import android.content.Context;import android.graphics.PointF;import android.graphics.drawable.Drawable;import android.os.Build;import android.util.AttributeSet;import android.view.View;import android.view.animation.AccelerateDecelerateInterpolator;import android.view.animation.AccelerateInterpolator;import android.view.animation.DecelerateInterpolator;import android.view.animation.Interpolator;import android.view.animation.LinearInterpolator;import android.widget.ImageView;import android.widget.RelativeLayout;import java.util.Random;public class PeriscopeLayout extends RelativeLayout {    private Interpolator line = new LinearInterpolator();//线性    private Interpolator acc = new AccelerateInterpolator();//加速    private Interpolator dce = new DecelerateInterpolator();//减速    private Interpolator accdec = new AccelerateDecelerateInterpolator();//先加速后减速    private Interpolator[] interpolators;    private int mHeight;    private int mWidth;    private LayoutParams lp;    private Drawable[] drawables;    private Random random = new Random();    private int dHeight;    private int dWidth;    public PeriscopeLayout(Context context) {        super(context);        init();    }    public PeriscopeLayout(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    public PeriscopeLayout(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init();    }    @TargetApi(Build.VERSION_CODES.LOLLIPOP)    public PeriscopeLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {        super(context, attrs, defStyleAttr, defStyleRes);        init();    }    private void init() {        //初始化显示的图片        drawables = new Drawable[3];        Drawable red = getResources().getDrawable(R.drawable.pl_red);        Drawable yellow = getResources().getDrawable(R.drawable.pl_yellow);        Drawable blue = getResources().getDrawable(R.drawable.pl_blue);        drawables[0] = red;        drawables[1] = yellow;        drawables[2] = blue;        //获取图的宽高 用于后面的计算        //注意 我这里3张图片的大小都是一样的,所以我只取了一个        dHeight = red.getIntrinsicHeight();        dWidth = red.getIntrinsicWidth();        //底部 并且 水平居中        lp = new LayoutParams(dWidth, dHeight);        lp.addRule(CENTER_HORIZONTAL, TRUE);//这里的TRUE 要注意 不是true        lp.addRule(ALIGN_PARENT_BOTTOM, TRUE);        // 初始化插补器        interpolators = new Interpolator[4];        interpolators[0] = line;        interpolators[1] = acc;        interpolators[2] = dce;        interpolators[3] = accdec;    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        mWidth = getMeasuredWidth();        mHeight = getMeasuredHeight();    }    public void addHeart() {        ImageView imageView = new ImageView(getContext());        //随机选一个        imageView.setImageDrawable(drawables[random.nextInt(3)]);        imageView.setLayoutParams(lp);        addView(imageView);        Animator set = getAnimator(imageView);        set.addListener(new AnimEndListener(imageView));        set.start();    }    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)]);        finalSet.setTarget(target);        return finalSet;    }    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;    }    private ValueAnimator getBezierValueAnimator(View target) {        //初始化一个贝塞尔计算器- - 传入       BezierEvaluator evaluator = new BezierEvaluator(getPointF(2), getPointF(1));        //这里最好画个图 理解一下 传入了起点 和 终点        ValueAnimator animator = ValueAnimator.ofObject(evaluator, new PointF((mWidth - dWidth) / 2, mHeight - dHeight), new PointF(random.nextInt(getWidth()), 0));        animator.addUpdateListener(new BezierListenr(target));        animator.setTarget(target);        animator.setDuration(3000);        return animator;    }    /**     * 获取中间的两个 点     *     * @param scale     */    private PointF getPointF(int scale) {        PointF pointF = new PointF();        pointF.x = random.nextInt((mWidth - 100));//减去100 是为了控制 x轴活动范围,看效果 随意~~        //再Y轴上 为了确保第二个点 在第一个点之上,我把Y分成了上下两半 这样动画效果好一些  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) {            //这里获取到贝塞尔曲线计算出来的的x y值 赋值给view 这样就能让爱心随着曲线走啦            PointF pointF = (PointF) animation.getAnimatedValue();            target.setX(pointF.x);            target.setY(pointF.y);            // 这里顺便做一个alpha动画            target.setAlpha(1 - animation.getAnimatedFraction());        }    }    private class AnimEndListener extends AnimatorListenerAdapter {        private View target;        public AnimEndListener(View target) {            this.target = target;        }        @Override        public void onAnimationEnd(Animator animation) {            super.onAnimationEnd(animation);            //因为不停的add 导致子view数量只增不减,所以在view动画结束后remove掉            removeView((target));        }    }}

贝塞尔曲线计算器BezierEvaluator.java

package me.yifeiyuan.periscopelayout;import android.animation.TypeEvaluator;import android.graphics.PointF;public class BezierEvaluator implements TypeEvaluator<PointF> {    private PointF pointF1;    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();//结果        point.x = timeLeft * timeLeft * timeLeft * (startValue.x)                + 3 * timeLeft * timeLeft * time * (pointF1.x)                + 3 * timeLeft * time * time * (pointF2.x)                + time * time * time * (endValue.x);        point.y = timeLeft * timeLeft * timeLeft * (startValue.y)                + 3 * timeLeft * timeLeft * time * (pointF1.y)                + 3 * timeLeft * time * time * (pointF2.y)                + time * time * time * (endValue.y);        return point;    }}

主页面是如何调用的呢？

final PeriscopeLayout periscopeLayout = (PeriscopeLayout) findViewById(R.id.periscope);        findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                periscopeLayout.addHeart();            }        });

这样就实现了，嗯代码不多，实现功能很简单，但原理要想搞懂就比较蛋疼了，贴上大神原文地址，

http://www.jianshu.com/p/03fdcfd3ae9c

仅供参考，源码就不上传了，就差了几张爱心的图片，大家可以稍作修改，以适应需求，谢谢大家。