在Swift中定制UIBarButtonItem

我试图在AppDelegate设置UIBarButtonItem的字体，如下UIBarButtonItem ：

 let barButton = UIBarButtonItem.appearance() barButton.setTitleTextAttributes([NSFontAttributeName: UIFont(name: "AvenirNext", size: 15], forState: UIControlState.Normal) 

但它引发了一个编译器错误说：

Cannot invoke 'init' with an argument list type '($T7, forState: UIControlState)

我不知道这意味着什么

我也试过了

barButton.titleTextAttributesForState(UIControlState.Normal) =[NSFontAttributeName...]

但似乎是不可转让的

我该怎么做？ 非常感谢！

Answer 1

UIFont的初始化UIFont返回一个可选项，因为它可能由于拼写错误的字体名称等原因而失败。

你必须打开它并检查：

 if let font = UIFont(name: "AvenirNext", size: 15) { barButton.setTitleTextAttributes([NSFontAttributeName: font], forState: UIControlState.Normal) } 

更新了Swift 3

 if let font = UIFont(name: "AvenirNext", size: 15) { barButton.setTitleTextAttributes([NSFontAttributeName:font], for: .normal) } 

Answer 2

设置自定义字体有点棘手，因为他们没有font和title属性。 希望这下面的答案会帮助你。

 let font = UIFont(name: "<your_custom_font_name>", size: <font_size>) var leftBarButtonItem = UIBarButtonItem(title: "<font_hex_code>", style: UIBarButtonStyle.Plain, target: self, action: "buttonClicked:") leftBarButtonItem.setTitleTextAttributes([NSFontAttributeName:font!], forState: UIControlState.Normal) self.navigationItem.leftBarButtonItem = leftBarButtonItem 

Answer 3

 if let font : UIFont = UIFont(name: "Roboto-Regular", size: 15) { cancelBarButton.setTitleTextAttributes([NSFontAttributeName: font], forState: UIControlState.Normal) doneBarButton.setTitleTextAttributes([NSFontAttributeName: font], forState: UIControlState.Normal) }