键盘隐藏时的iOS事件

Question

我需要控制，在显示键盘并按下完成按钮后，键盘隐藏。在iOS上隐藏键盘时会触发哪个事件？谢谢

Answer 1

是使用以下

//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];

onKeyboardHide

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

Answer 2

如果您想知道用户何时按下完成按钮，您必须采用UITextFieldDelegate协议，然后在您的View控制器中实现此方法：

斯威夫特3：

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

如果您只想知道键盘何时显示或隐藏，请使用Notification：

斯威夫特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

你可以听一个UIKeyboardWillHideNotification，只要键盘被解除就会发送它。