Android自定义View实现直播点赞特效

由于开发的需要，需要开发类似直播点赞特效的需求，于是自定义View来实现这种效果

案例图：

1.自定义View

import android.animation.Animator;import android.animation.AnimatorSet;import android.animation.ObjectAnimator;import android.animation.TypeEvaluator;import android.animation.ValueAnimator;import android.content.Context;import android.graphics.PointF;import android.graphics.drawable.Drawable;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 com.xinrui.ndkapp.R;import java.util.Random;/** * Created by liuyong * Data: 2017/8/8 * Github:https://github.com/MrAllRight * 直播点赞view */public class GivePraiseView extends RelativeLayout { private RelativeLayout.LayoutParams layoutParams;//图片布局参数 private PointF mPointF0, mPointF1, mPointF2, mPointF3;//通过3阶贝塞尔曲线控制图片的移动轨迹 private int mScreenWidth, mScreenHeight;//屏幕宽高 private Drawable[] mImageDrawables;//加载点赞红心图片，红黄蓝 private int mDrawableWidth, mDrawableHeight;//图片的宽高 private Random mRandom = new Random(); private int count = 0; private Interpolator[] interpolators = new Interpolator[4]; public GivePraiseView(Context context) { super(context); init(); } public GivePraiseView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } public GivePraiseView(Context context, AttributeSet attrs) { super(context, attrs); init(); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); mScreenHeight = h; mScreenWidth = w; } //初始化drawable，layoutParams private void init() { mImageDrawables = new Drawable[4]; mImageDrawables[0] = getResources().getDrawable(R.drawable.pl_blue); mImageDrawables[1] = getResources().getDrawable(R.drawable.pl_red); mImageDrawables[2] = getResources().getDrawable(R.drawable.pl_yellow); mImageDrawables[3] = getResources().getDrawable(R.drawable.pl_red); // 插值器 interpolators[0] = new AccelerateDecelerateInterpolator(); // 在动画开始与结束的地方速率改变比较慢，在中间的时候加速 interpolators[1] = new AccelerateInterpolator(); // 在动画开始的地方速率改变比较慢，然后开始加速 interpolators[2] = new DecelerateInterpolator(); // 在动画开始的地方快然后慢 interpolators[3] = new LinearInterpolator(); // 以常量速率改变 mDrawableWidth = mImageDrawables[0].getIntrinsicWidth(); mDrawableHeight = mImageDrawables[0].getIntrinsicHeight(); layoutParams = new LayoutParams(50, 50); layoutParams.addRule(ALIGN_PARENT_BOTTOM, TRUE); layoutParams.addRule(ALIGN_PARENT_RIGHT, TRUE); layoutParams.setMargins(0, 0, 60, 60);//放置在屏幕的右下角 //这里为了演示我们现在布局初始化的时候，放置一个imageview，颜色随机，设置点击屏幕出现点赞效果 ImageView iv = new ImageView(getContext()); iv.setLayoutParams(layoutParams); iv.setImageDrawable(mImageDrawables[0]); addView(iv); this.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { for(int i=0;i<10;i++) { addGivePraiseImg(count); count++; if (count == 4) count = 0; } } }); } //点击图片是添加imageview到布局中，并添加动画 private void addGivePraiseImg(int count) { final ImageView givepraiseImg = new ImageView(getContext()); givepraiseImg.setLayoutParams(layoutParams); givepraiseImg.setImageDrawable(mImageDrawables[count]); addView(givepraiseImg); addAnimator(givepraiseImg);//添加动画效果，动画分两部分，第一部分是产生图片时缩放和透明度，第二部是移动图片再进行透明度变化 } private void addAnimator(final ImageView imageView) { //点击的时候，让图片经过放大，缩放效果，之后再开始沿着贝塞尔曲线的轨迹移动 ObjectAnimator alpha = ObjectAnimator.ofFloat(imageView, 'alpha', 0.3f, 1f); ObjectAnimator scaleX = ObjectAnimator.ofFloat(imageView, 'scaleX', 0.2f, 1f); ObjectAnimator scaleY = ObjectAnimator.ofFloat(imageView, 'scaleY', 0.2f, 1f); AnimatorSet set = new AnimatorSet(); set.setDuration(100); set.playTogether(alpha, scaleX, scaleY); set.setTarget(imageView); set.addListener(new Animator.AnimatorListener() { @Override public void onAnimationStart(Animator animation) { } @Override public void onAnimationEnd(Animator animation) { //设置贝塞尔曲线移动效果 ValueAnimator va = getBzierAnimator(imageView);//第二部分动画 va.start(); } @Override public void onAnimationCancel(Animator animation) { } @Override public void onAnimationRepeat(Animator animation) { } }); set.start(); } //初始化贝塞尔曲线的4个点 private void initPointF() { mPointF0 = new PointF(mScreenWidth - 60 - 50, mScreenHeight - 60 - 50);//起点是初始化时的点 mPointF1 = new PointF(mRandom.nextInt(mScreenWidth), mRandom.nextInt((int) mPointF0.y));//第一个控制点必须要在起始点的上方 mPointF2 = new PointF(mRandom.nextInt(mScreenWidth), mRandom.nextInt((int) mPointF1.y));//第二个控制点必须在第一个点的上方 mPointF3 = new PointF(mRandom.nextInt(mScreenWidth), -50);//终点在屏幕的最顶部0-图片的高度 } /** * 自定义估值器计算图片移动的轨迹 * 计算公式参考贝塞尔曲线3阶计算公式 * 自定义估值器的方法可百度搜索 * 其中估值器定义返回的结果为PointF */ public class BezierEvaluator implements TypeEvaluator<PointF> { private PointF pointF1, pointF2; public BezierEvaluator(PointF p1, PointF p2) { this.pointF1 = p1; this.pointF2 = p2; } @Override public PointF evaluate(float t, PointF p0, PointF p3) { PointF point = new PointF(); point.x = p0.x * (1 - t) * (1 - t) * (1 - t) // + 3 * pointF1.x * t * (1 - t) * (1 - t)// + 3 * pointF2.x * t * t * (1 - t)// + p3.x * t * t * t;// point.y = p0.y * (1 - t) * (1 - t) * (1 - t) // + 3 * pointF1.y * t * (1 - t) * (1 - t)// + 3 * pointF2.y * t * t * (1 - t)// + p3.y * t * t * t;// return point; } } private ValueAnimator getValueAnimator(final ImageView imageView) { initPointF(); BezierEvaluator bezierEvaluator = new BezierEvaluator(mPointF1, mPointF2); ValueAnimator valueAnimator = ValueAnimator.ofObject(bezierEvaluator, mPointF0, mPointF3); valueAnimator.setDuration(3000); valueAnimator.setTarget(imageView); valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { //改变imageview位置实现移动效果 PointF point = (PointF) animation.getAnimatedValue(); imageView.setX(point.x); imageView.setY(point.y); imageView.setAlpha(1 - animation.getAnimatedFraction()); //动画结束移除imageview if (animation.getAnimatedFraction() >= 1) { removeView(imageView); } } }); return valueAnimator; } /** * 贝塞尔动画 * */ private ValueAnimator getBzierAnimator(final ImageView iv) { // TODO Auto-generated method stub PointF[] PointFs = getPointFs(iv); // 4个点的坐标 BezierEvaluator evaluator = new BezierEvaluator(PointFs[1], PointFs[2]); ValueAnimator valueAnim = ValueAnimator.ofObject(evaluator, PointFs[0], PointFs[3]); valueAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { // TODO Auto-generated method stub PointF p = (PointF) animation.getAnimatedValue(); iv.setX(p.x); iv.setY(p.y); iv.setAlpha(1- animation.getAnimatedFraction()); // 透明度 //动画结束移除imageview if (animation.getAnimatedFraction() >= 1) { removeView(iv); } } }); valueAnim.setTarget(iv); valueAnim.setDuration(3000); valueAnim.setInterpolator(interpolators[new Random().nextInt(4)]); return valueAnim; } private PointF[] getPointFs(ImageView iv) { // TODO Auto-generated method stub PointF[] PointFs = new PointF[4]; PointFs[0] = new PointF(); // p0 PointFs[0].x = (mScreenWidth- layoutParams.width)/ 2; PointFs[0].y = mScreenHeight - layoutParams.height; PointFs[1] = new PointF(); // p1 PointFs[1].x = new Random().nextInt(mScreenWidth); PointFs[1].y = new Random().nextInt(mScreenHeight /2) + mScreenHeight / 2 + layoutParams.height; PointFs[2] = new PointF(); // p2 PointFs[2].x = new Random().nextInt(mScreenWidth); PointFs[2].y = new Random().nextInt(mScreenHeight /2); PointFs[3] = new PointF(); // p3 PointFs[3].x = new Random().nextInt(mScreenWidth); PointFs[3].y = 0; return PointFs; }}

2.givepraise_layout.xml

<?xml version='1.0' encoding='utf-8'?><RelativeLayout xmlns:android='http://schemas.android.com/apk/res/android' android:layout_width='match_parent' android:layout_height='match_parent' android:background='@android:color/darker_gray'> <com.xinrui.ndkapp.view.GivePraiseView android:layout_width='match_parent' android:layout_height='match_parent'/> <!--<com.xinrui.ndkapp.view.LoveLayout--> <!--android:layout_width='match_parent'--> <!--android:layout_height='match_parent'/>--></RelativeLayout>

3.Activity 部分代码

import android.app.Activity;import android.os.Bundle;public class GivePraiseActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.givepraise_layout); }}

4.估值器的运算

p0坐标：x坐标（（布局的宽-心形图片宽）除以2），y坐标（布局的高 -心形图片高），这样获得的是顶部部水平中心点的坐标。p1坐标：x坐标（横坐标中的随机位置），y坐标（布局一半的高度 加上 0到一半高度范围内的随机坐标+心形的高度的一半）。这样取到的横坐标是在布局宽度之内的随机坐标，纵坐标为整个路径高度中部以上的随机坐标。p2坐标：与p1类似，横坐标是在布局宽度之内的随机坐标，纵坐标为整个路径高度中部以下的随机坐标。p3坐标：控件底部中心点知道4个坐标了，那么就可以开始计算路径

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