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
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）。
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？
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
好了，来吧各位，先来看看效果图：
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
OK，有了基本步骤，接下来就是根据步骤一步一步来进行了。
在开始绘制九宫格之前，我们先重写onMeasure方法，主要是为了让九宫格成为一个正方形，这样看起来体验更好，基本代码如下：
public class LotteryView extends SurfaceView{ /** * holder */ private SurfaceHolder mHolder; private List<Prize>prizes; private boolean flags; //抽奖开关 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 //旋转抽奖的方块默认颜色 private int transfer= 0xffff0000; private int MAX=50; //最大旋转次数 /** * 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); }}SurfaceView一般不是通过重写onDraw方法来绘制控件的，那么怎么获取到Canvas呢？主要是通过SurfaceHolder监听Callback事件来获取的
基本代码如下：
/** * holder */ private SurfaceHolder mHolder; public LotteryView(Context context, AttributeSet attrs) { super(context, attrs); mHolder = this.getHolder(); //监听CallBack mHolder.addCallback(this); } public LotteryView(Context context) { this(context,null); }现在有了对象SurfaceHolder对象，我们就可以获取到Canvas对象了，下面开始真正的绘制工作。
1.计算方块的具体显示位置
2.绘制每个奖品的方块
//绘制背景 private void drawBg(Canvas canvas) { //清除已绘制的图形 canvas.drawColor(Color.WHITE, Mode.CLEAR); //获取控件的宽度，因为要绘制九宫格，所以要平局分成三列 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(); //绘制方块 canvas.drawRect(rect, paint); } }解析：prizes 是一个集合，里面封装了奖品的一些基本信息，x1,y1,x2,y2分别是绘制奖品容器正方形的左上顶点和右下顶点，
通过观察发现，每一个方块位置都有一定的关系，即 x1=getPaddingLeft()+width*(Math.abs(index)%len);
y1=getPaddingTop()+width*(index/len); x2=x1+width; y2=y1+width;
有了这些点的关系，就可以通过canvas.drawRect(rect, paint);绘制出方块了
3.绘制奖品图
//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); } }通过了步骤1,2知道了方块的位置关系，就可以轻松的根据这些关系绘制出奖品来，Rect rect=new Rect(x1+width/6,y1+width/6,x2-width/6,y2-width/6);是让奖品比方块缩小一些，这样看起来会更自然一点。
4.计算旋转方块的下一步位置
//下一步 public int next(int position,int len){ int current=position; if(current+1<len){ return ++current; } if((current+1)%len==0&¤t<len*len-1){ return current+=len; } if(current%len==0){ return current-=len; } if(current<len*len){ return --current; } return current; }position是当前旋转方块的位置，len是3
5.绘制旋转方块
//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()); //得到下一步方块的位置 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); }6.监听点击开始按钮事件
private OnTransferWinningListener listener; public void setOnTransferWinningListener(OnTransferWinningListener listener){ this.listener=listener; } public interface OnTransferWinningListener{ /** * 中奖回调 * @param position */ void onWinning(int position); } @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 ; } }//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); } }); } } } }至此，基本的自定义工作已经差不多了，使用demo如下：
<?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:orientation="vertical" > <com.example.test.LotteryView android:id="@+id/nl" android:layout_width="match_parent" android:layout_height="match_parent" /></RelativeLayout>
public class HomeActivity extends Activity { LotteryView nl; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.act_home); nl=(LotteryView) findViewById(R.id.nl); int[]prizesIcon={R.drawable.danfan,R.drawable.meizi,R.drawable.iphone,R.drawable.f015,R.drawable.arrow,R.drawable.f040,R.drawable.ipad,R.drawable.spree_icon,R.drawable.spree_success_icon}; final List<Prize>prizes=new ArrayList<Prize>(); for(int x=0;x<9;x++){ Prize lottery=new Prize(); lottery.setId(x+1); lottery.setName("Lottery"+(x+1)); Bitmap bitmap = BitmapFactory.decodeResource(getResources(), prizesIcon[x]); lottery.setIcon(bitmap); if((x+1)%2==0){ lottery.setBgColor(0xff4fccee); }else if(x==4){ lottery.setBgColor(0xffffffff); }else{ lottery.setBgColor(0xff00ff34); } prizes.add(lottery); } nl.setPrizes(prizes); nl.setOnTransferWinningListener(new OnTransferWinningListener() { @Override public void onWinning(int position) { Toast.makeText(getApplicationContext(), prizes.get(position).getName(), Toast.LENGTH_SHORT).show(); } }); }}运行效果非常流畅
LotteryView整体demo：
package com.example.test;import java.util.List;import java.util.Random;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Point;import android.graphics.PorterDuff;import android.graphics.PorterDuff.Mode;import android.graphics.Rect;import android.os.SystemClock;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceHolder.Callback;import android.view.SurfaceView;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 璁╂ 娆＄ 跺 褰㈡ 藉 椤哄 杩 锛 濂藉 瑙ｉ 惧 寮 父涓 琛 涔 氨 锛 anvas涓 负绌猴 藉 跺 璁╀ 涓�娆″惊 澶 『 ╄ 琛 � 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&¤t<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); }}以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。
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