Android超简单实现九宫格抽奖

前言

如果有小伙伴想实现转盘抽奖效果的话请看我的另一篇文章《Android超简单实现自定义抽奖转盘效果》

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);
            }
        }
    }
}
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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);
        }
    }
}
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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();
    }
}
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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();
            }
        });
    }
}
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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);
    }
}
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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
    }
}

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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);
    }
}
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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();
            }
        });
    }
}
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效果展示

Android超简单实现九宫格抽奖

目录

前言

效果展示

实现步骤

项目源码：github.com/myml666/Nin…

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