如何通过Swift扩展实现委托方法

Question

My project is a mix of Obj-C and Swift, and I'm trying to extend my AppDelegate class with Swift.

So right now I have AppDelegate.m , AppDelegate.h , and AppDelegate.swift . Most of the methods are in the Obj-C file, but I'm trying to implement just one of the methods:

extension AppDelegate {

    func application(application: UIApplication, continueUserActivity userActivity: NSUserActivity, restorationHandler: ([AnyObject]?) -> Void) -> Bool {

    }
}

However it's complaining:

AppDelegate.swift:11:10: Method 'application(_:continueUserActivity:restorationHandler:)' with Objective-C selector 'application:continueUserActivity:restorationHandler:' conflicts with previous declaration with the same Objective-C selector

Is this a limitation of Swift extension? Or is there a way to implement this delegate method in my Swift extension file?

Answer 1

You cannot do something like that. AppDelegate has defined this method ( UIApplicationDelegate protocol says so).

The simplest solution would be to rewrite AppDelegate in swift.

You have also more difficult solution - remove UIApplicationDelegate from your AppDelegate and implement this protocol in your extension. It may raise unexpected errors if your AppDelegate is considerable size.