仿刮刮乐刮奖效果

该功能实现很简单，就是根据手指坐标位置在画板上画

1.效果图

          

2.代码实现

public class ErinieShow extends RelativeLayout {
    Context context;
    RelativeLayout bg;
    MyView MyView;
    int level;
    public ErinieShow(Context context, int level) {
        super(context);
        this.context = context;
        this.level = level;

        bg = new RelativeLayout(context);
        MyView = new MyView(context);
        bg.addView(MyView);
        addView(bg);

        int[] resolution = PhoneUtil.getResolution(context);
        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
                resolution[0], PhoneUtil.getFitHeight(context, 125));

        bg.setId(100001);
        bg.setLayoutParams(params);
        MyView.setLayoutParams(params);

        switch (level) {
        case 0:
            bg.setBackgroundResource(R.drawable.rewardlevel0);
            break;
        case 1:
            bg.setBackgroundResource(R.drawable.rewardlevel1);

            break;
        case 2:
            bg.setBackgroundResource(R.drawable.rewardlevel2);
            break;
        default:
            bg.setBackgroundResource(R.drawable.rewardlevel3);
            break;
        }

        MyView.init(Color.parseColor("#d3d3d3"), 30, 10);
    }
}

public class MyView extends TextView {

    private float TOUCH_TOLERANCE; // 填充距离，使线条更自然，柔和,值越小，越柔和。
    private Bitmap mBitmap;
    private Canvas mCanvas;
    private Paint mPaint;
    private Path mPath;
    private float mX, mY;
    private boolean isDraw = false;
    int time=0;

    public MyView(Context context) {
        super(context);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (isDraw) {
            mCanvas.drawPath(mPath, mPaint);
            canvas.drawBitmap(mBitmap, 0, 0, null);
        }
    }

    /**
     * 开启檫除功能
     *
     * @param bgColor
     *            覆盖的背景颜色
     * @param paintStrokeWidth
     *            触点（橡皮）宽度
     * @param touchTolerance
     *            填充距离,值越小，越柔和。
     */
    public void init(final int bgColor, final int paintStrokeWidth,
            float touchTolerance) {
        TOUCH_TOLERANCE = touchTolerance;
        // 设置画笔
        mPaint = new Paint();
        // mPaint.setAlpha(0);
        // 画笔划过的痕迹就变成透明色了
        mPaint.setColor(Color.BLACK); // 此处不能为透明色
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
        // 或者
        // mPaint.setAlpha(0);
        // mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));

        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND); // 前圆角
        mPaint.setStrokeCap(Paint.Cap.ROUND); // 后圆角
        mPaint.setStrokeWidth(paintStrokeWidth); // 笔宽

        // 痕迹
        mPath = new Path();
        // 覆盖
        LayoutParams layoutParams = getLayoutParams();
        int height = layoutParams.height;
        int width;
        if (getLayoutParams().width == LayoutParams.MATCH_PARENT) {
            width = 700;
        } else {
            width = layoutParams.width;
        }

        mBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);
        mCanvas = new Canvas(mBitmap);

        mCanvas.drawColor(bgColor);
        isDraw = true;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (!isDraw) {
            return true;
        }
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN: // 触点按下
            // touchDown(event.getRawX(),event.getRawY());
            touchDown(event.getX(), event.getY());
            invalidate();
            break;
        case MotionEvent.ACTION_MOVE: // 触点移动
            touchMove(event.getX(), event.getY());
            invalidate();
            break;
        case MotionEvent.ACTION_UP: // 触点弹起
            touchUp(event.getX(), event.getY());
            invalidate();
            break;
        default:
            break;
        }
        return true;
    }

    private void touchDown(float x, float y) {
        mPath.reset();
        mPath.moveTo(x, y);
        mX = x;
        mY = y;
    }

    private void touchMove(float x, float y) {
        float dx = Math.abs(x - mX);
        float dy = Math.abs(y - mY);
        if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
            mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
            mX = x;
            mY = y;
        }

    }

    private void touchUp(float x, float y) {
        mPath.lineTo(x, y);
        mCanvas.drawPath(mPath, mPaint);
        mPath.reset();
    }

}

源码下载http://download.csdn.net/detail/strawberry2013/7682865