[__NSCFTimer copyWithZone:]：无法识别的选择器发送到实例

    var searchDelayer:NSTimer?
    func searchBar(searchBar: UISearchBar!, textDidChange searchText: String!) {
        searchDelayer?.invalidate()
        searchDelayer = nil

        searchDelayer = NSTimer.scheduledTimerWithTimeInterval(1.5, target: self, selector: Selector("doDelayedSearch:"), userInfo: searchText, repeats: false)

    }

    func doDelayedSearch(text:String){
    ...
    }

为什么此代码崩溃并显示错误消息：

[__NSCFTimer copyWithZone:]: unrecognized selector sent to instance

Updated:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFTimer copyWithZone:]: unrecognized selector sent to instance 0x7f9c622ae7e0'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010c05b3e5 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x000000010ba42967 objc_exception_throw + 45
    2   CoreFoundation                      0x000000010c0624fd -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
    3   CoreFoundation                      0x000000010bfba7ec ___forwarding___ + 988
    4   CoreFoundation                      0x000000010bfba388 _CF_forwarding_prep_0 + 120
    5   CoreFoundation                      0x000000010bf32935 CFStringCreateCopy + 229
    6   libswiftFoundation.dylib            0x000000010dc41314 _TF10Foundation24_convertNSStringToStringFCSo8NSStringSS + 116
    7   MapCode                             0x000000010a1a567e _TToFC7MapCode17MapViewController15doDelayedSearchfS0_FSST_ + 62
    8   Foundation                          0x000000010b5fce94 __NSFireTimer + 83
    9   CoreFoundation                      0x000000010bfc34d4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
    10  CoreFoundation                      0x000000010bfc3095 __CFRunLoopDoTimer + 1045
    11  CoreFoundation                      0x000000010bf863cd __CFRunLoopRun + 1901
    12  CoreFoundation                      0x000000010bf859f6 CFRunLoopRunSpecific + 470
    13  GraphicsServices                    0x000000010ecfd9f0 GSEventRunModal + 161
    14  UIKit                               0x000000010c96b990 UIApplicationMain + 1282
    15  MapCode                             0x000000010a1b3fee top_level_code + 78
    16  MapCode                             0x000000010a1b402a main + 42
    17  libdyld.dylib                       0x000000010f9d7145 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

计时器回调函数必须是不带参数的函数，或者 一个函数取一个NSTimer作为单个参数。

在你的情况下，它应该是

func doDelayedSearch(timer: NSTimer) {
    let searchText = timer.userInfo as String
    // ...
}

旧答案：（以下说法正确，但不适用于此处）

定时器的目标（self在你的情况下）需要与 Objective-C 兼容， 即源自NSObject或标有@objc.

也可以看看在 Objective-C 中公开 Swift 接口 https://developer.apple.com/library/prerelease/mac/documentation/Swift/Conceptual/BuildingCocoaApps/InteractingWithObjective-CAPIs.html在里面 “使用 Swift 与 Cocoa 和 Objective-C”文档（重点是我的）：

The @objc属性使您的 Swift API 在 Objective-C 中可用，并且 Objective-C 运行时。换句话说，您可以使用@objc任何 Swift 方法、属性、下标、初始化器之前的属性， 或您想要从 Objective-C 代码使用的类。如果你的班级 继承自 Objective-C 类，编译器插入属性 为你。
...
当您使用时，此属性也很有用 Objective-C 类使用选择器来实现目标操作设计模式 - 例如，NSTimer or UIButton.