uiview 阴影

self.shadowView.layer.shadowOpacity = 0.6;// 阴影透明度

    self.shadowView.layer.shadowColor = [UIColor darkGrayColor].CGColor;// 阴影的颜色

    self.shadowView.layer.shadowRadius = 2;// 阴影扩散的范围控制

    self.shadowView.layer.shadowOffset  = CGSizeMake(1, 1);// 阴影的范围