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
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) } }