Question

我将代码编写为youtube视频教程，用于培训目的。这是我用同样的错误制作的第二个程序。我的iOS模拟器有问题吗？

这是代码：

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var Label: UILabel!
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    var leftSwipe = UISwipeGestureRecognizer(target:self,action: Selector("handleSwipes"))
     var rightSwipe = UISwipeGestureRecognizer(target:self,action: Selector("handleSwipes"))
     var upSwipe = UISwipeGestureRecognizer(target:self,action: Selector("handleSwipes"))
     var downSwipe = UISwipeGestureRecognizer(target:self,action: Selector("handleSwipes"))

    leftSwipe.direction = .Left
    rightSwipe.direction = .Right
    upSwipe.direction = .Up
    downSwipe.direction = .Down

    view.addGestureRecognizer(leftSwipe)
    view.addGestureRecognizer(rightSwipe)
    view.addGestureRecognizer(upSwipe)
    view.addGestureRecognizer(downSwipe)


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


func handleSwipes(sender:UISwipeGestureRecognizer){

    if (sender.direction == .Left){
        Label.text = "Left"
    }
    if (sender.direction == .Right){
        Label.text = "Right"
    }
    if (sender.direction == .Up){
        Label.text = "Up"
    }
    if (sender.direction == .Down){
        Label.text = "Down"
    }
}

}

错误是：

2015-08-03 15：13：09.545 SwipeGestures [14088：457164]    - [SwipeGestures.ViewController handleSwipes]：无法识别的选择器发送到实例0x79f92120 2015-08-03 15：13：09.550   SwipeGestures [14088：457164] *由于未被捕获而终止应用   异常＆＃39; NSInvalidArgumentException＆＃39;，原因：   ＆＃39; - [SwipeGestures.ViewController handleSwipes]：无法识别的选择器   发送到实例0x79f92120＆＃39;   * 第一次抛出调用堆栈：（0 CoreFoundation 0x002a9466 exceptionPreprocess + 182 1 libobjc.A.dylib
  0x01c98a97 objc_exception_throw + 44 2 CoreFoundation
  0x002b12c5 - [NSObject（NSObject）doesNotRecognizeSelector：] + 277 3
  CoreFoundation 0x001f9bc7 ___ forwarding _ + 1047     4 CoreFoundation 0x001f978e   _CF_forwarding_prep_0 + 14 5 UIKit 0x00f05057 _UIGestureRecognizerSendActions + 327 6 UIKit
  0x00f038d4 - [UIGestureRecognizer _updateGestureWithEvent：buttonEvent：]   + 561 7 UIKit 0x00f0591d - [UIGestureRecognizer _delayedUpdateGesture] + 60 8 UIKit 0x00f0929a _UIGestureRecognizerUpdate_block_invoke661 + 57 9
  UIKit 0x00f0915d   _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks + 317 10 UIKit 0x00efd066   _UIGestureRecognizerUpdate + 3720 11 UIKit 0x00b14c5b - [UIWindow _sendGesturesForEvent：] + 1356 12 UIKit
  0x00b15abf - [UIWindow sendEvent：] + 769 13 UIKit
  0x00adabb1 - [UIApplication sendEvent：] + 242 14 UIKit
  0x00aeabf6 _UIApplicationHandleEventFromQueueEvent + 21066 15 UIKit   0x00abebc7 _UIApplicationHandleEventQueue + 2300 16 CoreFoundation
  0x001cc98f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION   + 15 17 CoreFoundation 0x001c249d __CFRunLoopDoSources0 + 253 18 CoreFoundation 0x001c19f8 __CFRunLoopRun + 952 19 CoreFoundation
  0x001c137b CFRunLoopRunSpecific + 443 20 CoreFoundation
  0x001c11ab CFRunLoopRunInMode + 123 21图形服务
  0x0404e2c1 GSEventRunModal + 192 22 GraphicsServices
  0x0404e0fe GSEventRun + 104 23 UIKit
  0x00ac29b6 UIApplicationMain + 1526 24 SwipeGestures
  0x000c2e1e top_level_code + 78 25 SwipeGestures
  0x000c2e5b main + 43 26 libdyld.dylib
  0x02406ac9 start + 1）libc ++ abi.dylib：以uncaught终止   NSException类型的异常（lldb）

Answer 1

将下方的手势代码替换为

    var leftSwipe = UISwipeGestureRecognizer(target: self, action: "handleSwipes:")
    var rightSwipe = UISwipeGestureRecognizer(target: self, action: "handleSwipes:")
    var upSwipe = UISwipeGestureRecognizer(target: self, action: "handleSwipes:")
    var downSwipe = UISwipeGestureRecognizer(target: self, action: "handleSwipes:")

Answer 2

您忘了添加委托：

import UIKit

    class ViewController: UIViewController, UIGestureRecognizerDelegate {

Answer 3

在方法名称后添加冒号：

Selector("handleSwipes:")

这是因为handleSwipes在其定义中有一个参数。

Answer 4

尝试为UISwipeGestureRecognizer分配代理。 e.g：

class ViewController: UIViewController, UIGestureRecognizerDelegate {

和

leftSwipe.delegate = self

并实施：

func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
}

如果仍然失败，请按照其他人的建议在选择器名称中添加冒号。

如果您使用以下教程：http://www.raywenderlich.com/76020/using-uigesturerecognizer-with-swift-tutorial，您还可以阅读如果您有多个手势识别器，则需要代理人。默认情况下，只允许1。

当我使用UISwipeGestureRecognizer时，我获得了主题1：信号SIGABRT

4 个答案: