Android打造流畅九宫格抽奖

因为company项目中需要做九宫格抽奖活动，以前都没有做过类似的功能，虽然之前在浏览大神们的博客中，无意中也看到了好多关于抽奖的项目，但因为项目中没有需要，一直都没有点击进去看。这次不去看估计不行。直到公司计划要做抽奖功能，才迫不得已上网查找demo

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网上找了大半天，好不容易找到了几个demo，下载下来，解压缩包发现竟然里面空空如也，只有几张九宫格的图片，害我白白浪费了几个CSDN积分。后面在eoe网站那发现了一个demo，于是好开心，下载下来后马上导入到工程中，运行看了效果，九宫格是出来了，但效果真不敢恭维，主要是运行不流畅。但我还是进去稍微看了一下demo，基本思路是这样的：定义好九宫格界面，然后开启子线程不断循环修改状态，再通过handler发送消息到主线程中修改界面（子线程不能直接修改界面）。

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这个demo虽然功能上实现了，但不是我想要的效果，因为我这一关都不能通过，到了产品那边更加不用说了。那怎么办呢？

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于是我想到了一个控件，叫做SurfaceView,做游戏开发的同志们，应该对这个控件不陌生吧？首先介绍一下这个控件：
1.SurfaceView继承于View，多用于游戏开发中
2.可以直接在子线程中运行（其他UI控件都必须在主线程中运行的）。
3.一般的UI控件自定义时都是重写onDraw方法，但在SurfaceView中是通过SurfaceHolder获取Canvas来绘制图形的

这样，下面我开始根据我的想法，把自定义九宫格的步骤说一下。

步骤：

1.计算各位方块的位置
2.绘制每个奖品的方块（主要让界面更加好看）
3.绘制奖品图
4.计算旋转方块的下一步位置
5.绘制旋转方块
6.监听点击开始按钮事件

主要核心技术：
SurfaceView，SurfaceHolder

直接上代码

public class LotteryView extends SurfaceView implements Callback{    /**     * holder     */    private SurfaceHolder mHolder;    private List<Prize>prizes;    private boolean flags;    private int lottery=6;   //设置中奖号码    private int current=2;   //抽奖开始的位置    private int count=0;   //旋转次数累计    private int countDown;    //倒计次数，快速旋转完成后，需要倒计多少次循环才停止    private int transfer= 0xffff0000;    private int MAX=50;   //最大旋转次数    private OnTransferWinningListener listener;    public void setOnTransferWinningListener(OnTransferWinningListener listener){        this.listener=listener;    }    public interface OnTransferWinningListener{        /**         * 中奖回调         * @param position         */        void onWinning(int position);    }    /**     * 设置中奖号码     * @param lottery     */    public void setLottery(int lottery) {        if(prizes!=null&&Math.round(prizes.size()/2)==0){            throw new RuntimeException("开始抽奖按钮不能设置为中奖位置！");        }        this.lottery = lottery;    }    /**     * 设置转盘颜色     * @param transfer     */    public void setTransfer(int transfer) {        this.transfer = transfer;    }    /**     * 设置奖品集合     * @param prizes     */    public void setPrizes(List<Prize>prizes){        this.prizes=prizes;    }    @Override    public boolean onTouchEvent(MotionEvent event) {        handleTouch(event);        return super.onTouchEvent(event);    }    /**     * 触摸     * @param event     */    public void handleTouch(MotionEvent event) {        Point touchPoint=new Point((int)event.getX()-getLeft(),(int)event.getY());        switch(event.getAction()){        case MotionEvent.ACTION_DOWN:            Prize prize = prizes.get(Math.round(prizes.size())/2);            if(prize.isClick(touchPoint)){                if(!flags){                    setStartFlags(true);                    prize.click();                }            }            break ;        default:            break ;        }    }    private class SurfaceRunnable implements Runnable{        @Override        public void run() {            while(flags){                Canvas canvas=null;                try {                    canvas = mHolder.lockCanvas();                    drawBg(canvas);                    drawTransfer(canvas);                    drawPrize(canvas);                    controllerTransfer();                } catch (Exception e) {                    e.printStackTrace();                }finally{                    //涓轰簡璁╂瘡娆＄粯鍒跺浘褰㈡椂鑳藉椤哄埄杩涜锛屾渶濂藉皢瑙ｉ攣鏀惧埌寮傚父涓繘琛屽鐞嗭紝涔熷氨鏄锛屽鏋渃anvas涓嶄负绌猴紝閮藉皢鍏跺叧闂紝璁╀笅涓�娆″惊鐜兘澶熼『鍒╄繘琛岀粯鍒�                    if(canvas!=null)                        mHolder.unlockCanvasAndPost(canvas);                    }            }        }    }    //绘制背景    private void drawBg(Canvas canvas) {        canvas.drawColor(Color.WHITE, Mode.CLEAR);        int width = getMeasuredWidth()/3;        int x1=0;        int y1=0;        int x2=0;        int y2=0;        int len = (int) Math.sqrt(prizes.size());        for(int x=0;x<len*len;x++){            Prize prize = prizes.get(x);            int index=x;            x1=getPaddingLeft()+width*(Math.abs(index)%len);            y1=getPaddingTop()+width*(index/len);            x2=x1+width;            y2=y1+width;            Rect rect=new Rect(x1,y1,x2,y2);            Paint paint=new Paint();            paint.setColor(prize.getBgColor());            canvas.drawRect(rect, paint);        }    }    //绘制旋转的方块    private void drawTransfer(Canvas canvas) {        int width = getMeasuredWidth()/3;        int x1;        int y1;        int x2;        int y2;        int len = (int) Math.sqrt(prizes.size());        current=next(current, len);        x1=getPaddingLeft()+width*(Math.abs(current)%len);        y1=getPaddingTop()+width*((current)/len);        x2=x1+width;        y2=y1+width;        Rect rect=new Rect(x1,y1,x2,y2);        Paint paint=new Paint();        paint.setColor(transfer);        canvas.drawRect(rect, paint);    }    //控制旋转    private void controllerTransfer() {        if(count>MAX){            countDown++;            SystemClock.sleep(count*5);        }else{            SystemClock.sleep(count*2);        }        count++;        if(countDown>2){            if(lottery==current){                countDown=0;                count=0;                setStartFlags(false);                if(listener!=null){                    //切换到主线程中运行                    post(new Runnable() {                        @Override                        public void run() {                            listener.onWinning(current);                        }                    });                }            }        }    }    public void setStartFlags(boolean flags){        this.flags=flags;    }    //绘制奖品    private void drawPrize(Canvas canvas) {        int width = getMeasuredWidth()/3;        int x1=0;        int y1=0;        int x2=0;        int y2=0;        int len = (int) Math.sqrt(prizes.size());        for(int x=0;x<len*len;x++){            Prize prize = prizes.get(x);            int index=x;            x1=getPaddingLeft()+width*(Math.abs(index)%len);            y1=getPaddingTop()+width*(index/len);            x2=x1+width;            y2=y1+width;            Rect rect=new Rect(x1+width/6,y1+width/6,x2-width/6,y2-width/6);            prize.setRect(rect);            canvas.drawBitmap(prize.getIcon(), null, rect, null);        }    }    public void start() {        setLottery(getRandom());        ExecutorService service = Executors.newCachedThreadPool();        service.execute(new SurfaceRunnable());    }    //获取随机中奖数，实际开发中一般中奖号码是服务器告诉我们的    private int getRandom(){        Random r=new Random();        int nextInt =r.nextInt(prizes.size());        if(nextInt%(Math.round(prizes.size()/2))==0){            //随机号码等于中间开始位置，需要继续摇随机号            return getRandom();        }        return nextInt;    }    //下一步    public int next(int position,int len){        int current=position;        if(current+1<len){            return ++current;        }        if((current+1)%len==0&&current<len*len-1){            return current+=len;        }        if(current%len==0){            return current-=len;        }        if(current<len*len){            return --current;        }        return current;    }    public LotteryView(Context context, AttributeSet attrs) {        super(context, attrs);        mHolder = this.getHolder();        mHolder.addCallback(this);    }    public LotteryView(Context context) {        this(context,null);    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width,            int height) {    }    @Override    public void surfaceCreated(SurfaceHolder holder) {        Canvas canvas=null;        try {            canvas = mHolder.lockCanvas();            drawBg(canvas);            drawPrize(canvas);            Prize prize = prizes.get(Math.round(prizes.size()/2));            prize.setListener(new Prize.OnClickListener() {                @Override                public void onClick() {                    start();                }            });        } catch (Exception e) {            e.printStackTrace();        }finally{            if(canvas!=null)                mHolder.unlockCanvasAndPost(canvas);            }    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        setStartFlags(false);    }    /**      * 重新测量     */      @Override      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)      {          super.onMeasure(widthMeasureSpec, heightMeasureSpec);          int width = Math.min(getMeasuredWidth(), getMeasuredHeight());          setMeasuredDimension(width, width);      }}