iOS event when keyboard hides

Yes Use the following

//UIKeyboardDidHideNotification when keyboard is fully hidden//name:UIKeyboardWillHideNotification when keyboard is going to be hidden[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(onKeyboardHide:) name:UIKeyboardWillHideNotification object:nil];

And the onKeyboardHide

-(void)onKeyboardHide:(NSNotification *)notification{     //keyboard will hide}

If you want to know when the user press the Done button, you have to adopt the UITextFieldDelegate protocol, then in you View controller implement this method:

Swift 3:

func textFieldShouldReturn(_ textField: UITextField) -> Bool {    // this will hide the keyboard    textField.resignFirstResponder()    return true}

If you want to know simply when keyboard is shown or is hiding, use a Notification :

Swift 3:

NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: .UIKeyboardWillShow , object: nil)NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide(_:)), name: .UIKeyboardWillHide , object: nil)func keyboardWillShow(_ notification: NSNotification) {    print("keyboard will show!")    // To obtain the size of the keyboard:    let keyboardSize:CGSize = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue.size}func keyboardWillHide(_ notification: NSNotification) {    print("Keyboard will hide!")}

You can listen for a UIKeyboardWillHideNotification, it's sent whenever the keyboard is dismissed.