当前位置 : 主页 > 手机开发 > 其它 >

swift – 使用#selector传递参数

来源:互联网 收集:自由互联 发布时间:2021-06-11
我是 Swift的初学者,我正试图通过NotificationCenter启动一个功能. ‘ViewController.swift’中的观察者调用函数重载: override func viewDidLoad() { super.viewDidLoad() NotificationCenter.default.addObserver(self, s
我是 Swift的初学者,我正试图通过NotificationCenter启动一个功能. ‘ViewController.swift’中的观察者调用函数重载:

override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, selector: #selector(reload), name: NSNotification.Name(rawValue: "reload"), object: nil)
}

func reload(target: Item) {
    print(target.name)
    print(target.iconName)
}

…具有类Ítem的参数:

class Item: NSObject {
    let name: String
    let iconName: String
    init(name: String, iconName: String) {
        self.name = name
        self.iconName = iconName
    }
}

通知从“menu.swift”发布:

class menu: UIView, UITableViewDelegate, UITableViewDataSource {

let items: [Item] = {
    return [Item(name: "Johnny", iconName: "A"), Item(name: "Alexis", iconName: "B"), Item(name: "Steven", iconName: "C")]
}()

...

func tableView(_ tableView: UITableView, didSelectRowAt indexPath:
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "reload"), object: items[indexPath.row])
    }

如何将’menu.swift’中的对象项[indexPath.row]的值分配给’ViewController.swift’中函数reload的参数?

如果要在注册到NotificationCenter的类周围传递对象,则应将其放入传递给observer函数的通知对象的 .userInfo字典中:

NotificationCenter.default.addObserver(self, selector: #selector(reload), name: Notification(name: "reload"), object: nil)

let userInfo = ["item": items[indexPath.row]]
NotificationCenter.default.post(name: "reload", object: nil, userInfo: userInfo)

func reload(_ notification: Notification) {
  if let target = notification.userInfo?["item"] as? Item {
    print(target.name)
    print(target.iconName)
  }
}
网友评论