Github

官方文档

安装SnapKit

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'
use_frameworks!

target '<Your Target Name>' do
    pod 'SnapKit', '~> 3.2.0'
end

入门示例

import UIKit
import SnapKit

class ViewController: UIViewController {
    
    lazy var box = UIView()
    override func viewDidLoad() {
        super.viewDidLoad()
        //在屏幕中间设置个110正方形  
        box.backgroundColor = UIColor.green
        self.view.addSubview(box)
        box.snp.makeConstraints{ (make) -> Void in
            make.width.height.equalTo(110)
            make.center.equalTo(self.view)
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

image.png

NSLayoutAttributeCenterX 视图的中点的X值
NSLayoutAttributeCenterY 视图中点的Y值
NSLayoutAttributeBaseline 视图的基准线

修正约束语法:

.equalTo：等于
.lessThanOrEqualTo：小于等于
.greaterThanOrEqualTo：大于等于

倍率修正, 使用multipliedBy实例:

    override func viewDidLoad() {
        super.viewDidLoad()
    
        var box = UIView()
        box.backgroundColor = UIColor.green
        self.view.addSubview(box)
        box.snp.makeConstraints{ (make) -> Void in
            make.width.height.equalTo(110)
            make.center.equalTo(self.view)
        }
        
        var two = UILabel()
        two.backgroundColor = UIColor.yellow
        self.view.addSubview(two)
        //使two控件为box控件的0.3倍大小
        two.snp.makeConstraints{ (make) in
            make.center.equalTo(box)
            make.size.equalTo(box).multipliedBy(0.3)
        }

    }

        actionBut.snp.makeConstraints{ (make) in
//actionBut 与orangeBox偏移30            make.top.equalTo(orangeBox.snp.bottom).offset(30)
            make.width.equalTo(220)
            make.height.equalTo(35)
            make.centerX.equalTo(self.view)
        }