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当将项目代码更新为 swift 4 时，add.target 方法出现一些错误 我该如何解决这个错误？
//swift3
var chatLogController: ChatLogController? {
didSet {
sendButton.addTarget(chatLogController, action: #selector(ChatLogController.handleSend), for: .touchUpInside)
uploadImageView.addGestureRecognizer(UITapGestureRecognizer(target: chatLogController, action: #selector(ChatLogController.handleUploadTap)))
}
}
最佳答案
提示消息告诉你该做什么，在声明你的函数之前添加@obj。
@objc func handleSend(_ sender: UIGestureRecognizer){
...
}
原因是因为:
In Objective-C, a selector is a type that refers to the name of an Objective-C method. In Swift, Objective-C selectors are represented by the
Selectorstructure, and can be constructed using the#selectorexpression. To create a selector for a method that can be called from Objective-C, pass the name of the method, such as#selector(MyViewController.tappedButton(_:)). To construct a selector for a property’s Objective-C getter or setter method, pass the property name prefixed by thegetter:orsetter:label, such as#selector(getter: MyViewController.myButton).
阅读更多 here , 在 Apple 文档中。
关于ios - 如何将 addTarget 方法更新为 swift 4，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46392832/