swift - 将 "function with parameter"作为参数传递

Question

这不编译

func showAlert(_ title: String, message: String, 
  onOk: (()->())? = nil,
  onAnotherAction:((anotherActionTitle : String)-> Void)? = nil) {
    let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)

    let ok = UIAlertAction(title: "OK", style: .default) { (action) in
        onOk?()
    }

    let anotherAction = UIAlertAction(title: anotherActionTitle, style: .default) { (action) in
        onAnotherAction?()
    }

    alertController.addAction(ok)
    alertController.addAction(anotherAction)

    ...
}

这个编译

func showAlert(_ title: String, message: String,
  onOk: (()->())? = nil,
  onAnotherAction:((String)-> Void)? = nil)

但是，我必须为 onAnotherAction() 的标题 anotherActionTitle 声明另一个参数。

有没有办法使第一种方法起作用？谢谢!

Answer 1

However, I have to declare another parameter for the title anotherActionTitle of onAnotherAction()

不，您不必那样做。只需将其作为整个函数的常规参数即可:

func showAlert(_ title: String, message: String,
               onOk: (()->())? = nil,
               anotherActionTitle: String? = nil,
               onAnotherAction: (()->())? = nil) {

然后您的函数的其余部分将编译并正常工作。