SwipeBackLayout.java 文件源码

private void drawShadow(Canvas canvas, View child) {
    final Rect childRect = mTmpRect;
    child.getHitRect(childRect);

    if ((mEdgeFlag & EDGE_LEFT) != 0) {
        mShadowLeft.setBounds(childRect.left - mShadowLeft.getIntrinsicWidth(), childRect.top,
                childRect.left, childRect.bottom);
        mShadowLeft.setAlpha((int) (mScrimOpacity * FULL_ALPHA));
        mShadowLeft.draw(canvas);
    }

    if ((mEdgeFlag & EDGE_RIGHT) != 0) {
        mShadowRight.setBounds(childRect.right, childRect.top,
                childRect.right + mShadowRight.getIntrinsicWidth(), childRect.bottom);
        mShadowRight.setAlpha((int) (mScrimOpacity * FULL_ALPHA));
        mShadowRight.draw(canvas);
    }

    if ((mEdgeFlag & EDGE_BOTTOM) != 0) {
        mShadowBottom.setBounds(childRect.left, childRect.bottom, childRect.right,
                childRect.bottom + mShadowBottom.getIntrinsicHeight());
        mShadowBottom.setAlpha((int) (mScrimOpacity * FULL_ALPHA));
        mShadowBottom.draw(canvas);
    }
}