Swift 2.0 constraintsWithVisualFormat

Question

我在 Swift 2.0 中遇到 AutoLayout 的奇怪问题

self.webView = WKWebView()
self.view.addSubview(self.webView!)

var viewBindingsDict: NSMutableDictionary = NSMutableDictionary()
viewBindingsDict.setValue(self.webView, forKey: "webView")

self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[webView]|", options: 0, metrics: nil, views: viewBindingsDict))

self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[webView]|", options: 0, metrics: nil, views: viewBindingsDict))

我收到错误:

'String' is not convertible to 'StringLiteralConvertible'

对于 "H:|[webView]|" 和 "V:|[webView]|"

不知道是不是漏了什么

更新:

Answer 1

您应该将viewBindigsDict 更改为

var viewBindingsDict = [String: AnyObject]()
viewBindingsDict["webView"] = webView

正如评论和格式选项中所建议的，您不能使用 0，而是:

view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[webView]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: viewBindingsDict))

或如@MartinR 所建议的更简单:

view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[webView]|", options: [], metrics: nil, views: viewBindingsDict))