swift语言点评十三-Lazy

Lazy Stored Properties

A lazy stored property is a property whose initial value is not calculated until the first time it is used. You indicate a lazy stored property by writing the lazy modifier before its declaration.

let kScreenWidth = UIScreen.mainScreen().bounds.size.width let kScreenHeight = UIScreen.mainScreen().bounds.size.heightclassViewController: UIViewController{ lazy var wkWebView: WKWebView= { () -> WKWebViewinlet tempWebView = WKWebView() tempWebView.navigationDelegate = selfreturntempWebView }() override func viewDidLoad() {super.viewDidLoad() let someURL = ... let request: NSURLRequest= NSURLRequest(URL: someURL)self.wkWebView.loadRequest(request)self.wkWebView.frame = CGRectMake(0, 0, kScreenWidth, kScreenHeight)self.view.addSubview(self.wkWebView) } }

作者：foolishlionel
链接：https://www.jianshu.com/p/af0702a91e92
來源：简书
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