CALayer 绘制边框线不能被遮挡

一般我们在布局视图时遵从一个原则: 后加的先显示。

下面简述下我遇到的问题：图片未能盖住背景视图的边框，边框使用的是CALayer绘制，但其余部分都能遮盖住，难道CALayer不能被遮挡？

实现代码如下：

self.bgView = [[UIView alloc]init];
    self.bgView.layer.cornerRadius = 5.0;
    [self.bgView borderWidth:1 andBorderColor:CC_ICOME(@"#B8D2FF6B")];
    self.bgView.backgroundColor = CC_ICOME(@"F8FBFF8F");
    [self.contentView addSubview:self.bgView];
    [self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(self.contentView.mas_top);
        make.left.equalTo(self.contentView.mas_left).offset(10);
        make.right.equalTo(self.contentView.mas_right).offset(-10);
        make.bottom.equalTo(self.moreImage.mas_top);
    }];


    [self.bgView addSubview:self.leftImage];
    [self.leftImage mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.bgView).offset(-2);
        make.top.equalTo(self.bgView.mas_top).offset(9);
        make.height.mas_equalTo(22);
        make.width.mas_equalTo(6);
    }];

先看修改后效果：线被完美遮当

实现代码如下：

self.bgView = [[UIView alloc]init];
    self.bgView.layer.cornerRadius = 5.0;
    [self.bgView borderWidth:1 andBorderColor:CC_ICOME(@"#B8D2FF6B")];
    self.bgView.backgroundColor = CC_ICOME(@"F8FBFF8F");
    [self.contentView addSubview:self.bgView];
    [self.bgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(self.contentView.mas_top);
        make.left.equalTo(self.contentView.mas_left).offset(10);
        make.right.equalTo(self.contentView.mas_right).offset(-10);
        make.bottom.equalTo(self.moreImage.mas_top);
    }];


    [self.contentView addSubview:self.leftImage];
    [self.leftImage mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.bgView).offset(-2);
        make.top.equalTo(self.bgView.mas_top).offset(9);
        make.height.mas_equalTo(22);
        make.width.mas_equalTo(6);
    }];

综上所述：后加的先显示，针对CALayer来说，必须是在同一个等级