swift - swift 3 "nearly match optional requirement"中的所有 6 个应用程序委托(delegate)函数 - 这是什么？怎么修？

Question

昨晚下载了 xcode 8.2 beta，转换了我的大部分代码，但现在卡在了关于应用程序委托(delegate)的六个功能的黄色警告符号:

var window: UIWindow?


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.
    return true
}

  func applicationWillResignActive(application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

  func applicationDidEnterBackground(application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

  func applicationWillEnterForeground(application: UIApplication) {
    // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}

 func applicationDidBecomeActive(application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

func applicationWillTerminate(application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
}

我可以用任一方法“修复”每个函数

  Rename to application(_:didFinishLaunchingWithOptions:)' to      satisfy this requirement

  Make 'application(application:didFinishLaunchingWithOptions:)'       private to slince this warning 

或

Add '@nonobjc' to silence this warning

考虑到我以前没有见过这三个选项，有人介意解释一下以及解决或忽略它们的任何选项吗？

Answer 1

这都是“重命名”的一部分，Swift 3 对方法第一个参数外部化规则的更改。

因此，执行第一个选项:放入 _ 使 _ application:(而不是 application: 简单明了)每种情况下第一个参数的名称。否则，application 将被外部化，并且 Objective-C 会将这些方法视为被称为 applicationWithApplication...，这不是您希望发生的事情。

其他任何一个都不要做。您不想从 Objective-C 中隐藏这些方法(private 或 @nonobjc)；您希望 Objective-C 看到它们，尤其是将它们视为应用委托(delegate)协议(protocol)方法。