swift-懒加载的写法

• 懒加载的格式如下：

• lazy var demoView: UIView = {
      let v = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
      v.backgroundColor = UIColor.redColor()
  
      return v
  }()

  • 懒加载本质上是一个闭包
  • 以上代码可以改写为以下格式

  let demoLazy = { () -> UIView in
      let v = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
      v.backgroundColor = UIColor.redColor()
  
      return v
  }
  
  lazy var demoView: UIView = self.demoLazy()
  

  • 懒加载的简单写法

  lazy var dataList = [String]()