效果展示

实现步骤

1.生成抽奖矩形：

其中每个矩形的宽高相同，长度为整个控件宽度的1/3。

代码展示

public class NineLuckPan extends View { private Paint mPaint; private ArrayList<RectF> mRects;//存储矩形的集合 private float mStrokWidth = 5;//矩形的描边宽度 private int mRectSize;//矩形的宽和高（矩形为正方形） private int[] mItemColor = {Color.GREEN, Color.YELLOW};//矩形的颜色 public NineLuckPan(Context context) { this(context, null); } public NineLuckPan(Context context, @Nullable AttributeSet attrs) { this(context, attrs, 0); } public NineLuckPan(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } /** * 初始化数据 */ private void init() { mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setStyle(Paint.Style.FILL); mPaint.setStrokeWidth(mStrokWidth); mRects = new ArrayList<>(); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); mRectSize = Math.min(w, h) / 3;//获取矩形的宽和高 mRects.clear();//当控件大小改变的时候清空数据 initRect();//重新加载矩形数据 } /** * 加载矩形数据 */ private void initRect() { //加载前三个矩形 for (int x = 0; x < 3; x++) { float left = x * mRectSize; float top = 0; float right = (x + 1) * mRectSize; float bottom = mRectSize; RectF rectF = new RectF(left, top, right, bottom); mRects.add(rectF); } //加载第四个 mRects.add(new RectF(getWidth() - mRectSize, mRectSize, getWidth(), mRectSize * 2)); //加载第五~七个 for (int y = 3; y > 0; y--) { float left = getWidth() - (4 - y) * mRectSize; float top = mRectSize * 2; float right = (y - 3) * mRectSize + getWidth(); float bottom = mRectSize * 3; RectF rectF = new RectF(left, top, right, bottom); mRects.add(rectF); } //加载第八个 mRects.add(new RectF(0, mRectSize, mRectSize, mRectSize * 2)); //加载第九个 mRects.add(new RectF(mRectSize, mRectSize, mRectSize * 2, mRectSize * 2)); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); drawRects(canvas); } /** * 画矩形 * * @param canvas */ private void drawRects(Canvas canvas) { for (int x = 0; x < mRects.size(); x++) { RectF rectF = mRects.get(x); if (x == 8) {//中心的矩形背景为白色 mPaint.setColor(Color.WHITE); canvas.drawRect(rectF, mPaint); } else { mPaint.setColor(mItemColor[x % 2]); canvas.drawRect(rectF, mPaint); } } }}

效果展示

2.添加奖品图片：

我们在矩形的中心点画出图片，图片的宽高都为矩形宽高的1/2，其中矩形的中心点通过rectF.centerX()和rectF.centerY()获取。

代码展示（为了方便只展示部分代码）

public class NineLuckPan extends View { private int[] mImgs = {R.drawable.ic_df, R.drawable.ic_jt, R.drawable.ic_mf, R.drawable.ic_scjx, R.drawable.ic_scng, R.drawable.ic_thl, R.drawable.ic_x, R.drawable.ic_xc, R.drawable.ic_j}; @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); drawRects(canvas);//画矩形 drawImages(canvas);//画图片 } /** * 画图片 * * @param canvas */ private void drawImages(Canvas canvas) { for (int x = 0; x < mRects.size(); x++) { RectF rectF = mRects.get(x); float left = rectF.centerX() - mRectSize / 4; float top = rectF.centerY() - mRectSize / 4; canvas.drawBitmap(Bitmap.createScaledBitmap(BitmapFactory.decodeResource(getResources(), mImgs[x]), mRectSize / 2, mRectSize / 2, false), left, top, null); } }}

效果展示

3.实现抽奖动画：

这里我们使用ValueAnimator使数字从0递增到我们的中奖位置比如3，然后改变递增所在的位置的矩形的背景以实现抽奖的效果，另外为了让用户感到逼真我们需要让抽奖色块多转几圈，同时我们需要将下一次的开始位置设为上一次的结束位置。

代码展示（为了方便只展示部分代码）

NineLuckPan:

public class NineLuckPan extends View { private int mRepeatCount = 3;//转的圈数 private int mLuckNum = 3;//最终中奖位置 private int mPosition = -1;//抽奖块的位置 private int mStartLuckPosition = 0;//开始抽奖的位置 /** * 画矩形 * @param canvas */ private void drawRects(Canvas canvas) { for (int x = 0;x<mRects.size();x++){ RectF rectF = mRects.get(x); if(x == 8){ mPaint.setColor(Color.WHITE); canvas.drawRect(rectF, mPaint); }else { mPaint.setColor(mItemColor[x%2]); if(mPosition == x){ mPaint.setColor(Color.BLUE); } canvas.drawRect(rectF, mPaint); } } } public void setPosition(int position){ mPosition = position; invalidate(); } /** * 开始动画 */ public void startAnim(){ ValueAnimator valueAnimator = ValueAnimator.ofInt(mStartLuckPosition, mRepeatCount * 8 + mLuckNum).setDuration(5000); valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { int position = (int) animation.getAnimatedValue(); setPosition(position%8); } }); valueAnimator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { mStartLuckPosition = mLuckNum; } }); valueAnimator.start(); }}

Activity:

public class MainActivity extends AppCompatActivity { private NineLuckPan luckpan; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); luckpan = (NineLuckPan) findViewById(R.id.luckpan); luckpan.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { luckpan.startAnim(); } }); }}

效果展示

虽然效果实现了但是我们发现好像点哪里都能启动动画，因此我们需要调整一下代码使只有点击中心的矩形才开始动画。

//（为了方便只展示部分代码）public class NineLuckPan extends View { private boolean mClickStartFlag = false;//是否点击中间矩形的标记 //这样需要我们将Activity里的启动动画的逻辑删掉 @Override public boolean onTouchEvent(MotionEvent event) { if(event.getAction() == MotionEvent.ACTION_DOWN){ if(mRects.get(8).contains(event.getX(),event.getY())){ mClickStartFlag = true; }else { mClickStartFlag = false; } return true; } if(event.getAction() == MotionEvent.ACTION_UP){ if(mClickStartFlag){ if(mRects.get(8).contains(event.getX(),event.getY())){ startAnim();//判断只有手指落下和抬起都在中间的矩形内才开始抽奖 } mClickStartFlag = false; } } return super.onTouchEvent(event); }}

4.实现动态设置参数：

效果基本实现了，接下来就需要实现动态设置数据了。

代码展示（这里为了方便只展示部分代码）

public class NineLuckPan extends View { private int mLuckNum = 3;//最终中奖位置 private int [] mImgs = {R.drawable.ic_df,R.drawable.ic_jt,R.drawable.ic_mf,R.drawable.ic_scjx,R.drawable.ic_scng,R.drawable.ic_thl,R.drawable.ic_x,R.drawable.ic_xc,R.drawable.ic_j}; private String[] mLuckStr = {"豆腐","鸡腿","米饭","卷心菜","南瓜","糖葫芦","大虾","香肠"};//这是抽奖的提示信息 public int getmLuckNum() { return mLuckNum; } public void setmLuckNum(int mLuckNum) { this.mLuckNum = mLuckNum; } public int[] getmImgs() { return mImgs; } public void setmImgs(int[] mImgs) { this.mImgs = mImgs; invalidate();//要注意设置完后要进行重绘 } public String[] getmLuckStr() { return mLuckStr; } public void setmLuckStr(String[] mLuckStr) { this.mLuckStr = mLuckStr; invalidate();;//要注意设置完后要进行重绘 }}

5.添加抽奖结果回调

这里需要在动画结束的回调里加入我们自定义的回调函数。

代码展示（这里为了方便只展示部分代码）

public class NineLuckPan extends View { private OnLuckPanAnimEndListener onLuckPanAnimEndListener; public OnLuckPanAnimEndListener getOnLuckPanAnimEndListener() { return onLuckPanAnimEndListener; } public void setOnLuckPanAnimEndListener(OnLuckPanAnimEndListener onLuckPanAnimEndListener) { this.onLuckPanAnimEndListener = onLuckPanAnimEndListener; } /** * 开始动画 */ private void startAnim(){ ValueAnimator valueAnimator = ValueAnimator.ofInt(mStartLuckPosition, mRepeatCount * 8 + mLuckNum).setDuration(5000); valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { int position = (int) animation.getAnimatedValue(); setPosition(position%8); } }); valueAnimator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { mStartLuckPosition = mLuckNum; //在动画结束的回调函数里加入我们自定义的回调函数 if(onLuckPanAnimEndListener!=null){ onLuckPanAnimEndListener.onAnimEnd(mPosition,mLuckStr[mPosition]); } } }); valueAnimator.start(); } public interface OnLuckPanAnimEndListener{ void onAnimEnd(int position,String msg); }}

Activity代码：

public class MainActivity extends AppCompatActivity { private NineLuckPan luckpan; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); luckpan = (NineLuckPan) findViewById(R.id.luckpan); luckpan.setOnLuckPanAnimEndListener(new NineLuckPan.OnLuckPanAnimEndListener() { @Override public void onAnimEnd(int position, String msg) { Toast.makeText(MainActivity.this, "位置："+position+"提示信息："+msg, Toast.LENGTH_SHORT).show(); } }); }}

效果展示

源码地址：

https://github.com/myml666/NineLuckPan

到这里就结束啦！

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