[__NSCFTimer copyWithZone：]：发送到实例的无法识别的选择器 [英] [__NSCFTimer copyWithZone:]: unrecognized selector sent to instance

问题描述

    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：

Why this code crashes with error message:

[__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

推荐答案

定时器回调函数必须是不带参数的函数，或
a函数将 NSTimer 作为单个参数。

The timer callback function must be either a function without arguments, or a function taking a NSTimer as a single argument.

在您的情况下，它应该是

In your case, it should be

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

---

Old回答：（以下是正确的，但不适用于此处）

---

Old answer: (The following is correct but does not apply here)

计时器的目标（ self 在你的情况下）需要与Objective-C兼容，
即派生自 NSObject 或标有 @objc 。

The target of the timer (self in your case) needs to be compatible with Objective-C, i.e. derived from NSObject or marked with @objc.

另请参阅
在
使用Swift with Cocoa和Objective-C文档（强调我的）中展示Objective-C中的Swift接口：

@objc 属性使您的Swift API在Objective-C和$中可用b $ b Objective-C运行时。换句话说，您可以在任何要使用的Swift方法，属性，下标，初始值设定项，
或类之前使用 @objc
属性来自Objective-C代码。如果你的
类继承自Objective-C类，编译器会为你插入属性
。

...

这个属性在你正在使用
使用选择器实现目标动作设计模式的Objective-C类 - 例如， NSTimer 或者 UIButton 。

The @objc attribute makes your Swift API available in Objective-C and the Objective-C runtime. In other words, you can use the @objc attribute before any Swift method, property, subscript, initializer, or class that you want to use from Objective-C code. If your class inherits from an Objective-C class, the compiler inserts the attribute for you.
...
This attribute is also useful when you’re working with Objective-C classes that use selectors to implement the target-action design pattern—for example, NSTimer or UIButton.

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