//@mg:masksToBounds必须为NO否者阴影没有效果//    cell.layer.masksToBounds = NO;    cell.layer.contentsScale = [UIScreen mainScreen].scale;    cell.layer.shadowOpacity = 0.75f;    cell.layer.shadowRadius = 4.0f;    cell.layer.shadowOffset = CGSizeMake(0,0);    cell.layer.shadowPath = [UIBezierPath bezierPathWithRect:cell.bounds].CGPath;    //设置缓存    cell.layer.shouldRasterize = YES;    //设置抗锯齿边缘    cell.layer.rasterizationScale = [UIScreen mainScreen].scale;