在UIAction中为UIKit中的菜单使用操作和选择器

Question

我试图在UIAction中为我的菜单项在UIKit中使用动作。所以，对于第一个按钮，我无法应用动作。它显示了错误“无法在范围内找到‘动作’”。

我真的很想在这种情况下使用选择器。我想知道对选择器采取行动的最佳方式是什么

 class MessageViewController : UIViewController, UITableViewDelegate {
    
        private lazy var first = UIAction(title: "Edit", image: UIImage(systemName: "pencil.circle"), attributes: [], state: .off) { [self]_ in
        action:  #selector(self.RightSideBarButtonItemTapped(_:))
    
        }
        private lazy var second = UIAction(title: "Second", image: UIImage(systemName: "pencil.circle"), attributes: [.destructive], state: .on) { action in
            print("Second")
            #selector(self.sendMessageRightSideBarButtonItemTapped(_:))
        }
        
        private lazy var third = UIAction(title: "Third", image: UIImage(systemName: "pencil.circle"), attributes: [], state: .off) { action in
            print("third")
        }
    
        private lazy var elements: [UIAction] = [first]
        private lazy var menu = UIMenu(title: "new", children: elements)
    
        override func viewDidLoad() {
            super.viewDidLoad()
    
     view.backgroundColor = .white
                    navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: nil)
                    menu = menu.replacingChildren([first, second, third])
                    if #available(iOS 14.0, *) {
                        navigationItem.rightBarButtonItem?.menu = menu
                    }
    }

从“Hangar Rash”尝试解决方案

       private lazy var first = UIAction(title: "Edit", image: UIImage(systemName: "pencil.circle"), attributes: [], state: .off)
        { [unowned self] action in
            self.RightSideBarButtonItemTapped(_:)
    // Getting error on this line which says its " Function is unused "
            
        }
    
    override func viewDidLoad() {}
override func viewDidAppear(_ animated: Bool) {}

        @objc func RightSideBarButtonItemTapped(_ sender:UIBarButtonItem!)
        {
            let vc = IceWorldView()
                present(vc, animated: true)
        }

Answer 1

你的第一个行动有两个问题：

action

• there's语法错误

1. 不需要使用#selector.只需直接调用方法

更改：

private lazy var first = UIAction(title: "Edit", image: UIImage(systemName: "pencil.circle"), attributes: [], state: .off) { [self]_ in
    action:  #selector(self.RightSideBarButtonItemTapped(_:))
}

至：

private lazy var first = UIAction(title: "Edit", image: UIImage(systemName: "pencil.circle"), attributes: [], state: .off) { [unowned self] action in
    self.RightSideBarButtonItemTapped(someButton)
}

RightSideBarButtonItemTapped需要一个UIBarButtonItem参数，但菜单中没有一个参数。您可以创建一个虚拟按钮实例来传入，也可以更改RightSideBarButtonItemTapped，这样它就不会接受任何参数。不管怎么说，你似乎并没有使用传递的发送者。

在第二个操作中也修正了#selector的使用。