将代码转换为Swift 4.2时,通知名称出错

Question

在Swift 4.2之前,下面的代码运行正常:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

当我单击"修复"选项时,它变为:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: NSNotification.Name.UIResponder.keyboardWillShowNotification, object: nil)

但它仍然标记错误.这是解释:

Type 'NSNotification.Name' has no member 'UIResponder'

然后我试图删除'UIResponder':

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: NSNotification.Name.

......但我不知道该如何完成它.

Answer 1

正确的形式是:

UIResponder.keyboardWillShowNotification

...所以,你的代码变成:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: UIResponder.keyboardWillShowNotification)

这是Xcode 10的一个已知问题.自动修复 - 在更正通知名称时,它无法正常使用Swift 4.2.

在Swift 4.2中,许多Notification.Name实例成为其他类中的实例变量.例如,keyboardWillShowNotification现在是一个实例变量UIResponder.