objective-c - NSTimer 在触发时导致 "unrecognized selector"崩溃

Question

我正在使用 NSTimer 来运行动画(现在只称它为 myMethod)。但是，它会导致崩溃。

代码如下:

@implementation SecondViewController


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.


- (void) myMethod
{
    NSLog(@"Mark Timer Fire");

}


- (void)viewDidLoad
{ 
[super viewDidLoad];



NSLog(@"We've loaded scan");

[NSTimer scheduledTimerWithTimeInterval:2.0
                                 target:self
                               selector:@selector(myMethod:)
                               userInfo:nil
                                repeats:YES];

animationTimer = [NSTimer scheduledTimerWithTimeInterval: 1.0 target:self selector:@selector(myMethod:) userInfo:nil repeats: YES];


}

这是崩溃期间的输出

-[SecondViewController myMethod:]: unrecognized selector sent to instance 0x4b2ca40 2012-06-21 12:19:53.297 Lie Detector[38912:207] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[SecondViewController myMethod:]: unrecognized selector sent to instance 0x4b2ca40'

那么我做错了什么？

Answer 1

我在使用 Swift 时遇到了这个问题。可能不是很明显，在 Swift 中我发现 NSTimer 的目标对象必须是 NSObject。

class Timer : NSObject {
   init () { super.init() }
   func schedule() {
      NSTimer.scheduledTimerWithTimeInterval(2.0,
                             target: self,
                             selector: "myMethod",
                             userInfo: nil,
                            repeats: true)
  }
  func myMethod() {
     ...
  }
}

希望这对某人有帮助。