键盘隐藏时的iOS事件

Question

I need to control, after keyboard is shown and done button is pressed, when keyboard hides. Which event is triggered when hides keyboard on iOS? Thank you

Answer 1

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
}

Answer 2

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!")
}

Answer 3

您可以收听UIKeyboardWillHideNotification ，只要键盘被解除就会发送。