最后说的
我有A类，它包含B的实例。在A类中，我将A的函数作为选择器传递给B的方法.B使用此选择器来注册通知。但是，当通知进入时，它无法运行选择器并显示＆＃34;无法识别的选择器发送到实例＆＃34;。如果我把我想要在B级做的所有事情都转移到A级，那就有用了。但是，我希望它们分开，以使它看起来更有条理。我对Objective-C和Swift相当新，因此，在这种情况下，我不知道如何将selector作为参数传递。 Swift中的答案会很棒。
ViewController.swift
class ViewController: UIViewController {
var sessionCtrl : GKSessionControllerH!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
sessionCtrl = GKSessionControllerH()
// register notifications
registerNotification()
}
func registerNotification() {
sessionCtrl.registerNotification(GKGesture.Up, gestureHandler: "gestureUpHandler")
}
func gestureUpHandler() {
dispatch_async(dispatch_get_main_queue()) {
self.slidesViewCtrl!.prevPage()
}
}
}
GKSessionControllerH.swift
class GKSessionControllerH: NSObject, WCSessionDelegate {
func handleGestureContent(content : AnyObject?) {
// retrieve gesture
let gesture = GKGesture(rawValue: content as! String)!
print("Handheld device receives \(gesture)")
// post notification
let notificationName = "ReceiveGesture\(gesture.rawValue)"
NSNotificationCenter.defaultCenter().postNotificationName(notificationName, object: nil)
}
func registerNotification(gesture : GKGesture, gestureHandler : Selector) {
let notificationName = "ReceiveGesture\(gesture.rawValue)"
NSNotificationCenter.defaultCenter().addObserver(self, selector: gestureHandler, name: notificationName, object: nil)
}
}
调试信息
2015-07-08 17:26:26.534 Slider[4608:1719498] -[Slider.GKSessionControllerH gestureDownHandler]: unrecognized selector sent to instance 0x7f912857a420
2015-07-08 17:26:26.543 Slider[4608:1719498] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Slider.GKSessionControllerH gestureDownHandler]: unrecognized selector sent to instance 0x7f912857a420'
*** First throw call stack:
(
0 CoreFoundation 0x000000010430dca5 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x00000001060f1dcd objc_exception_throw + 48
2 CoreFoundation 0x0000000104315fcd -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x00000001042634ea ___forwarding___ + 970
4 CoreFoundation 0x0000000104263098 _CF_forwarding_prep_0 + 120
5 CoreFoundation 0x00000001042db09c __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12
6 CoreFoundation 0x00000001042daddb _CFXRegistrationPost + 427
7 CoreFoundation 0x00000001042dab42 ___CFXNotificationPost_block_invoke + 50
8 CoreFoundation 0x000000010431d432 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1618
9 CoreFoundation 0x00000001041d3538 _CFXNotificationPost + 632
10 Foundation 0x00000001048bb3c4 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66
11 Slider 0x00000001040f4e0e _TFC6Slider20GKSessionControllerH20handleGestureContentfS0_FGSqPSs9AnyObject__T_ + 1086
12 Slider 0x00000001040f4689 _TFC6Slider20GKSessionControllerH7sessionfS0_FTCSo9WCSession17didReceiveMessageGVSs10DictionarySSPSs9AnyObject___T_ + 825
13 Slider 0x00000001040f49b7 _TToFC6Slider20GKSessionControllerH7sessionfS0_FTCSo9WCSession17didReceiveMessageGVSs10DictionarySSPSs9AnyObject___T_ + 119
14 WatchConnectivity 0x00000001060c18cd WatchConnectivity + 35021
15 libdispatch.dylib 0x0000000106ab2b11 _dispatch_call_block_and_release + 12
16 libdispatch.dylib 0x0000000106ad280d _dispatch_client_callout + 8
17 libdispatch.dylib 0x0000000106ab92ec _dispatch_queue_drain + 2200
18 libdispatch.dylib 0x0000000106ab88ed _dispatch_queue_invoke + 233
19 libdispatch.dylib 0x0000000106abae9b _dispatch_root_queue_drain + 1412
20 libdispatch.dylib 0x0000000106aba912 _dispatch_worker_thread3 + 111
21 libsystem_pthread.dylib 0x0000000106e11637 _pthread_wqthread + 729
22 libsystem_pthread.dylib 0x0000000106e0f40d start_wqthread + 13
)
libc++abi.dylib: terminating with uncaught exception of type NSException
答案 0 :(得分：17)
这是控制台输出中的重要线索：
- [Slider.GKSessionControllerH gestureDownHandler]：无法识别的选择器发送到实例0x7f912857a420
因此，问题在于，gestureDownHandler并未尝试在ViewController上致电GKSessionControllerH，而是将自己注册为通知的接收方。
我们需要传入选择器和对象来调用选择器。
func registerNotification(gesture: GKGesture, gestureHandler: AnyObject, selector: Selector) {
let notificationName = "ReceiveGesture\(gesture.rawValue)"
NSNotificationCenter.defaultCenter().addObserver(gestureHandler, selector: gestureHandler, name: notificationName, object: nil)
}
现在，注册：
sessionCtrl.registerNotification(.Up, gestureHandler: self, selector: "gestureUpHandler")
或者，可以说更像Swift，我们可以采用更基于闭包的方法。
首先，让我们GKSessionControllerH收到通知，然后我们会向其传递一个关闭，它会在收到通知时跟踪通话。
在GKSessionControllerH，
var gestureActions = [()->Void] // an array of void-void closures
func gestureHandler() {
for action in gestureActions {
action()
}
}
func registerNotification(gesture: GKGesture, action:()->Void) {
let notificationName = "ReceiveGesture\(gesture.rawValue)"
NSNotificationCenter.defaultCenter().addObserver(self, selector: "gestureHandler", name: notificationName, object: nil)
}
现在，我们传入一个闭包（可以是一个方法）：
在ViewController：
func registerNotification() {
sessionCtrl.registerNotification(.Up, action: gestureUpHandler)
}
现在显然，这将需要更多的逻辑来处理所有不同的手势类型，但它的要点就在这里。