Swift 语法糖then

then是一个swift初始化库,只有80几行的代码库,确可以让初始化变得很优雅。

1.使用then初始化AnyObject,这里以初始化控件为例

lazy var label = UILabel().then({
        $0.text = "label"
        $0.textColor = .blue
    })

let redView = UIView().then { (make) in
        make.backgroundColor = .red
        make.frame = CGRect(x: 50, y: 50,  100, height: 100)
    }

let button = UIButton().then ({
            $0.setTitle("点我", for: .normal)
            $0.setTitleColor(.red, for: .normal)
        })

2.then和SnapKit一起使用的方式

let button1 = UIButton().then { (make) in
            make.setTitle("登录", for: .normal)
            make.setTitleColor(.black, for: .normal)
            view.addSubview(make)
            
            make.snp.makeConstraints({ (make) in
                make.top.left.right.equalTo(0)
                make.height.equalTo(100)
            })
        }

let button2 = UIButton().then({
        $0.setTitle("登录", for: .normal)
        $0.setTitleColor(.black, for: .normal)
        view.addSubview($0)
        
        $0.snp.makeConstraints({
            $0.top.equalTo(button1.snp.bottom)
            $0.left.right.equalTo(0)
            $0.height.equalTo(50)
        })
      })

3.其他用法

let newFrame = oldFrame.with {
          $0.size.width = 200
          $0.size.height = 100
    }
    newFrame.width // 200
    newFrame.height // 100

UserDefaults.standard.do {
        $0.set("devxoul", forKey: "username")
        $0.set("devxoul@gmail.com", forKey: "email")
        $0.synchronize()
    }