项目需要实现点赞的效果，在网上找个一个解决方案：
http://www.jianshu.com/p/03fdcfd3ae9c
初用一些还好，暴力测试一下发现很卡，不太好用。并且像如此麻烦的动画，确实该用
SurfaceView来实现。于是就找资料，没有找到直接能用的。最后，还是自己来实现。先看效果图：
这里写图片描述
点击屏幕时，从屏幕底部飘出随机的一个赞的图标。
demo中两个核心的东西：
- SurfaceView的基本使用；
- 正弦波的参数设置；
直接在代码中看注释吧
/**
* 直播页面点赞控件，采用SurfaceView绘制
* 与普通控件使用方法类似，点赞是只需要调用addBubble(int)即可
* @author huamm
*/
public class PraiseView extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private AnimThread mAnimThread; // 绘制UI的线程
private Paint mPaint; // 绘制需要使用的画刷
private int mWidth; // 控件的宽度
private int mHeight; // 控件的高度
private Bitmap[] mDrawables; // 存放需要展示的图
private int[] mDrawableResIDs; // 存放需要展示的图
private final LinkedList<Bubble> mTempList = new LinkedList<Bubble>(); // 用于遍历时临时存放
private final LinkedList<Bubble> mBubbles = new LinkedList<Bubble>(); // 用于存放点赞信息
private OnBubbleStateListener mOnBubbleStateListener; // 点赞开始和停止的监听
private Random mRandom = new Random(); // 用于产生随机数
public PraiseView(Context context, AttributeSet attrs) {
super(context, attrs);
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setFormat(PixelFormat.TRANSPARENT);
mPaint = new Paint();
mDrawableResIDs = new int[] {
R.drawable.praise_eight,
R.drawable.praise_one,
R.drawable.praise_third,
R.drawable.praise_two,
R.drawable.praise_five,
R.drawable.praise_four,
R.drawable.praise_seven,
R.drawable.praise_six,
};
mDrawables = new Bitmap[mDrawableResIDs.length];
}
@Override
protected void onDraw(final Canvas canvas) {
if (canvas != null) {
canvas.drawColor(Color.TRANSPARENT, Mode.CLEAR); // 清空界面
mTempList.clear();
synchronized (mBubbles) {
mTempList.addAll(mBubbles);
}
for (Bubble bubble : mTempList) {
Coordinates coords = bubble.coordinates;
// 设置透明度
if (coords.y < mHeight * 0.25) {
if (coords.y < 0) {
mPaint.setAlpha(0);
} else {
mPaint.setAlpha((int) (coords.y * 1020f / mHeight));
}
} else if (coords.y > mHeight * 0.75 && coords.y < mHeight) {
mPaint.setAlpha((int) ((1 - coords.y * 1f / mHeight) * 1020));
} else {
mPaint.setAlpha(255);
}
// 设置缩放
if (coords.y < mHeight && coords.y > mHeight*0.75) {
bubble.scale = 0.5f + (mHeight - coords.y)*2f/mHeight;
canvas.scale(bubble.scale, bubble.scale, mWidth/2, mHeight);
} else {
canvas.scale(1f, 1f);
}
canvas.drawBitmap(bubble.bitmap, coords.x, coords.y, mPaint); // 绘制图像
// 设置下次绘制坐标
coords.y = coords.y - dip2px(2);
coords.x = getXbyY(bubble, coords.y);
// 判断是否已经不可见
if (coords.y < -dip2px(20)) {
synchronized (mBubbles) {
mBubbles.remove(bubble);
if (mBubbles.size() <= 0 && mOnBubbleStateListener != null) {
mOnBubbleStateListener.onEnd();
}
}
}
}
}
}
private int getXbyY(Bubble bubble, int y) {
// float startx = delta - amplifier * (float) (Math.sin(phase * 2 *
// (float) Math.PI / 360.0f + 2 * Math.PI * frequency / height * x));
float startx = bubble.delta - bubble.amplifier * (float) (Math.sin(bubble.data1 + bubble.data2 * y));
return (int) startx;
}
public void addBubble(int count) {
if (mBubbles.size() <= 0 && mOnBubbleStateListener != null) {
mOnBubbleStateListener.onStart();
}
for (int i = 0; i < count; i++) {
Bubble bubble = new Bubble(getRandBitmap());
bubble.delay = mRandom.nextInt(100 * count); // 避免同时增加很多个赞
bubble.coordinates.x = 0;
bubble.coordinates.y = mHeight + bubble.delay;
bubble.delta += bubble.delta - getXbyY(bubble, mHeight);
synchronized (mBubbles) {
mBubbles.add(bubble);
}
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mAnimThread = new AnimThread(holder, this);
mAnimThread.setRunning(true);
mAnimThread.start();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
this.mWidth = width;
this.mHeight = height;
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
mAnimThread.setRunning(false);
while (retry) {
try {
mAnimThread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
/**
* 随机获取一个bitmap
* @return
*/
private Bitmap getRandBitmap() {
int n = mRandom.nextInt(mDrawableResIDs.length);
Bitmap bitmap = mDrawables[n];
if (bitmap == null || bitmap.isRecycled()) {
BitmapFactory.Options opts = new BitmapFactory.Options();
opts.inMutable = true;
bitmap = BitmapFactory.decodeResource(getResources(), mDrawableResIDs[n], opts);
mDrawables[n] = bitmap;
}
return bitmap;
}
/**
* 绘制UI的线程，只要是调用PraiseView.onDraw(canvas);
* 并且做了锁保护（固定用法，不要轻易修改）
* ###########################################
*/
class AnimThread extends Thread {
private SurfaceHolder holder;
private PraiseView praiseView;
private boolean running = true;
public AnimThread(SurfaceHolder holder, PraiseView snowView) {
this.praiseView = snowView;
this.holder = holder;
}
@SuppressLint("WrongCall")
@Override
public void run() {
while (running) {
Canvas canvas = null;
try {
canvas = holder.lockCanvas();
synchronized (holder) {
praiseView.onDraw(canvas);
}
} finally {
if (canvas != null) {
holder.unlockCanvasAndPost(canvas);
}
}
}
}
public void setRunning(boolean b) {
running = b;
}
}
/**
* 保存赞的信息，主要有坐标信息，路径相关
* ###########################################
*/
class Bubble {
public Bitmap bitmap;
public Coordinates coordinates;
// 路径相关
public int delay; // 延迟距离
public float frequency = 1.5f; // 频率
public float phase = 45; // 相位
public float delta = 500; // 偏移量
public float amplifier = 500; // 振幅
public float scale = 1.0f; // 缩放
// 用于缓存计算结果，避免在onDraw中计算过量
public double data1;
public double data2;
public Bubble(Bitmap bitmap) {
this.bitmap = bitmap;
float rFloat = mRandom.nextFloat();
frequency = 0.5f + rFloat*0.5f;
phase = rFloat * 360;
amplifier = mWidth / 8 + rFloat * mWidth / 8;
// int n = dip2px(rFloat * 20);
// delta = mWidth / 2 + (n % 2 == 1 ? n * (-1) : n); // 偏移量
delta = mWidth / 2; // 偏移量
coordinates = new Coordinates();
coordinates.y = mHeight;
data1 = phase * 2 * (float) Math.PI / 360.0f;
data2 = 2 * Math.PI * frequency / mHeight;
}
/**
* Contains the coordinates of the graphic.
*/
public class Coordinates {
public int x;
public int y;
}
}
private float scale = -1f; // 缓存起来
private int dip2px(float dpValue) {
if (scale < 0) {
scale = getResources().getDisplayMetrics().density;
}
return (int) (dpValue * scale + 0.5f);
}
/**
* 设置点赞开始和结束事件
* @param bubbleStateListener
*/
public void setOnBubbleStateListener(OnBubbleStateListener bubbleStateListener){
this.mOnBubbleStateListener = bubbleStateListener;
}
public interface OnBubbleStateListener {
public void onStart();
public void onEnd();
}
}
使用起来与一般控件无差别，直接复制去用吧
源码链接：https://github.com/brian512/AndroidDemo
