效果图：

 

思路：(self为自定义的View，里面有三个按钮和两个分隔线)

一、按钮约束：使三个按钮等宽分布

1、按钮一：上、左、下和self对齐，宽和“按钮二”对齐

2、按钮二：上、下和self对齐，宽和“按钮三”对齐，左和“按钮二”右对齐

3、按钮三：上、右、下和self对齐，左和“按钮二”右对齐

二、竖线约束：

1、分隔线一：CenterY和self对齐，CenterX和“按钮一”右对齐

2、分隔线二：CenterY和self对齐，CenterX和“按钮二”右对齐

1 private func setupUI(){ 2         // 添加三个按钮 3         let retweetButton = addChildButton(imageName: "timeline_icon_retweet",title: "转发") 4         let commentButton = addChildButton(imageName: "timeline_icon_comment",title: "评论") 5         let unlikeButton = addChildButton(imageName: "timeline_icon_unlike",title: "赞") 6          7         // 添加两个分隔线 8         let firstLineView = addChildLineView() 9         let secondLineView = addChildLineView()10         11         // 设置三个按钮的约束12         retweetButton.snp_makeConstraints { (make) in13             make.top.leading.bottom.equalTo(self)14             make.width.equalTo(commentButton)15         }16         commentButton.snp_makeConstraints { (make) in17             make.top.bottom.equalTo(self)18             make.leading.equalTo(retweetButton.snp_trailing)19             make.width.equalTo(unlikeButton)20         }21         unlikeButton.snp_makeConstraints { (make) in22             make.top.trailing.bottom.equalTo(self)23             make.leading.equalTo(commentButton.snp_trailing)24         }25         26         // 设置两个分隔线约束27         firstLineView.snp_makeConstraints { (make) in28             make.centerX.equalTo(retweetButton.snp_trailing)29             make.centerY.equalTo(self)30         }31         secondLineView.snp_makeConstraints { (make) in32             make.centerX.equalTo(commentButton.snp_trailing)33             make.centerY.equalTo(self)34         }35     }36     37     // 创建button按钮38     private func addChildButton(imageName:String,title:String) -> UIButton{39         let button = UIButton()40         button.setImage(UIImage(named:imageName), for: .normal)41         button.setTitle(title, for: .normal)42         button.titleLabel?.font = UIFont.systemFont(ofSize: 14)43         button.setTitleColor(UIColor.darkGray, for: .normal)44         button.setBackgroundImage(UIImage(named:"timeline_card_bottom_background"), for: .normal)45         button.adjustsImageWhenHighlighted = false46         addSubview(button)47         return button48     }49     50     // 创建竖线视图51     private func addChildLineView() -> UIImageView{52         let imageView = UIImageView(image:UIImage(named:"timeline_card_bottom_line"))53         addSubview(imageView)54         return imageView55     }