android 实现蒙版引导

来源：互联网发布：什么社交软件好编辑：程序博客网时间：2024/05/01 10:18

实现效果如下图

实现方法：
1.计算镂空区域的坐标
2.新建一张canvas,绘制半透明蒙版
3.将PorterDuffXfermode设为Clear
4.绘制镂空区域到canvas

具体见代码：

设置要镂空的view:

public void setTarget(View v) {        mTragetView = v;    }

计算镂空区域的坐标：

int[] location = new int[2];                        mTragetView.getLocationInWindow(location);                        mRectStartPoints = new Point(location[0], location[1]);                        rectWidth = mTragetView.getWidth();                        rectHeight = mTragetView.getHeight();

绘制蒙版：

@Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        if (mBitmap == null) {            mBitmap = Bitmap.createBitmap(canvas.getWidth(), canvas.getHeight(), Bitmap.Config.ARGB_4444);            mTempCanvas = new Canvas(mBitmap);        }        mPaint.setColor(Color.parseColor("#000000"));        mPaint.setAlpha(188);        mTempCanvas.drawRect(0, 0, mTempCanvas.getWidth(), mTempCanvas.getHeight(), mPaint);        mTransparentPaint.setColor(getResources().getColor(android.R.color.transparent));        mTransparentPaint.setXfermode(mPorterDuffXfermode);        mTempCanvas.drawRect(mRectStartPoints.x , mRectStartPoints.y , mRectStartPoints.x + rectWidth                , mRectStartPoints.y + rectHeight, mTransparentPaint);        canvas.drawBitmap(mBitmap , 0 , 0 , mPaint);    }

禁用镂空区域以外的touch事件：

@Override    public boolean onTouchEvent(MotionEvent event) {        float x = event.getX();        float y = event.getY();        //禁用镂空区域以外的触摸事件,如果触摸事件在镂空区域内,执行回调        if ((x > mRectStartPoints.x && x < mRectStartPoints.x + rectWidth) &&                (y > mRectStartPoints.y && y < mRectStartPoints.y + rectHeight)                && event.getAction() == MotionEvent.ACTION_UP) {            setVisibility(View.GONE);            ((ViewGroup) ((Activity) getContext()).getWindow().getDecorView()).removeView(ShowTipsView.this);            if (mListener != null) {                mListener.onTouch();            }        }        return super.onTouchEvent(event);    }

源码地址：github地址

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