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

Question

    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

更新:

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

Answer 1

定时器回调函数必须是不带参数的函数,或者是NSTimer作为单个参数的函数.

在你的情况下,它应该是

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

旧答案:(以下是正确的,但不适用于此处)

计时器的目标(self在您的情况下)需要与Objective-C兼容,即从中派生NSObject或标记@objc.

另请参阅 "使用Swift with Cocoa和Objective-C"文档(强调我的)在Objective-C中公开Swift接口:

该@objc属性使您的Swift API在Objective-C和Objective-C运行时可用.换句话说,您可以@objc 在任何要从Objective-C代码中使用的Swift方法,属性,下标,初始化程序或类之前使用该属性.如果您的类继承自Objective-C类,则编译器会为您插入属性.
...
当您使用使用选择器实现目标操作设计模式的NSTimer Objective-C类时,此属性也很有用- 例如,或UIButton.