Android实现超简单九宫格抽奖功能-技术圈

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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