鍵盤存在時向上或向下移動檢視

注意： 這僅適用於 iOS 提供的內建鍵盤

迅速：

為了使 UIViewController 的檢視在呈現時增加幀的原點並在隱藏時減少它，將以下函式新增到你的類：

func keyboardWillShow(notification: NSNotification) {

    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        if self.view.frame.origin.y == 0{
            self.view.frame.origin.y -= keyboardSize.height
        }
    }

}

func keyboardWillHide(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        if self.view.frame.origin.y != 0{
            self.view.frame.origin.y += keyboardSize.height
        }
    }
}

在你的類的 viewDidLoad() 方法中，新增以下觀察者：

NotificationCenter.default.addObserver(self, selector: #selector(Login.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(Login.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil) 

這適用於任何螢幕尺寸，使用鍵盤的 height 屬性。

Objective-C 的：

要在 Objective-C 中執行相同的操作，可以使用以下程式碼：

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

- (void)keyboardWillShow:(NSNotification *)notification
{
    CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    [UIView animateWithDuration:0.3 animations:^{
        CGRect f = self.view.frame;
        f.origin.y = -keyboardSize.height;
        self.view.frame = f;
    }];
}

-(void)keyboardWillHide:(NSNotification *)notification
{
    [UIView animateWithDuration:0.3 animations:^{
        CGRect f = self.view.frame;
        f.origin.y = 0.0f;
        self.view.frame = f;
    }];
}