iOS - NSNotification 无效选择器

Question

我无法理解为什么会发生这种情况，但由于某种原因，当 NSNotification 第二次触发这种情况时:

-[UITableViewCel lContentView imageFound:]: unrecognized selector sent to instance 0x1cd837e0 2013-08-12 16:32:24.340 poundtaxi[7483:907] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UITableViewCellContentView imageFound:]: unrecognized selector sent to instance 0x1cd837e0'

* 第一个抛出调用堆栈:(0x344d92a3 0x3c17e97f 0x344dce07 0x344db531 0x34432f68 0x3442a037 0x34d40599 0xd7d9f 0x33d64145 0x3c59611f 0x 3c5954b7 0x3c596dcb 0x344acf3b 0x3441febd 0x3441fd49 0x37fe32eb 0x36335301 0xb963d 0x3c5b5b20) libc++abi.dylib: 终止调用抛出异常

这是执行的代码块:

-(void)imageFound:(NSNotification *)aNotification {
    NSDictionary* userInfo = [aNotification userInfo];
    Picture *aPicture = (Picture *) [userInfo objectForKey:@"picture"];
    UIImage *image = (UIImage *) [userInfo objectForKey:@"image"];

    aPicture.highResPicture = image;
    self.count++;
 }

Answer 1

很可能已注册的观察者对象在作为观察者被删除之前已被释放。永远记住在 dealloc 中删除通知中心观察者。