应用程序坠毁在textview.becomeFirstResponder

Question

我的应用程序有时会崩溃在textView.becomeFirstResponder()的电话。抛出的错误是奇怪：

-[UITextSelectionView keyboardShownWithNotif:]: unrecognized selector sent to instance 0x16899070 

有时是：

-[UIImageView keyboardShownWithNotif:]: unrecognized selector sent to instance 0x178e2610 

我没有补充通知监听器：

NotificationCenter.default.addObserver(self, selector: #selector(keyboardShown(notif:)), name: .UIKeyboardWillShow, object: nil) 
NotificationCenter.default.addObserver(self, selector: #selector(keyboardHidden), name: .UIKeyboardWillHide, object: nil) 

但观察者是我定义的自定义视图，为什么系统发送通知到UITextSelectionView或UIImageView？

在iOS 8.4.1中找到，未在iOS中复制9.

这里发生了什么？

Answer 1

seems like you added an notif. observer to show/hide keyboard. 
Try to remove observer in dealloc method 

- (void) dealloc { 
     [[NSNotificationCenter defaultCenter] removeObserver:self]; //Or whichever observer you want to remove 
} 

Answer 2

在SWIFT 3：

override func viewWillDisappear(_ animated: Bool) { 
    super.viewWillDisappear(animated) 
      NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window) 
      NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window) 
} 

或

deinit { 
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window) 
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window) 
}