ios - "Missing argument for parameter ' 样式' in call"创建系统UIBarButtonItem 错误

Question

我不明白为什么编译器要求在这个系统风格的 UIBarButtonItem 初始值设定项中为样式参数提供参数——它首先没有那个参数。帮助？这是 Swift 的错误吗？

class ExpensesViewController: UIViewController {

    lazy var newExpenseBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: Selector("newExpenseBarButtonItemTapped:"))

    func newExpenseBarButtonItemTapped() {

    }

}

Answer 1

这将删除编译器错误消息:

class ExpensesViewController: UIViewController {

    lazy var newExpenseBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.UIBarButtonSystemItemAdd.value, 
                 target:self, action:Selector("newExpenseBarButtonItemTapped:"))

    func newExpenseBarButtonItemTapped() {

    }

}

.Add 不是有效值