ios - 在 iOS Objective-c 中粘在键盘上的自定义 UIView

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我想制作一个粘在键盘上的自定义 UIView，我使用了输入附件 View ，但是当键盘离开时它不会留在我的 View Controller 上。在 iOS Objective-C 中，如何让我限制在 View Controller 底部的 UIView 粘在键盘上(如输入附件 View )？

Answer 1

为 View 的底部约束添加一个 IBOutlet。我假设它是 ViewController View 的直接 subview ，当键盘隐藏时它应该位于底部。

@IBOutlet weak var bottomConstraint: NSLayoutConstraint!

在 viewWillAppear 中订阅键盘通知:

NotificationCenter.default.addObserver(self, selector: #selector(showKeyboard), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(hideKeyboard), name: UIResponder.keyboardWillHideNotification, object: nil)

在 viewDidDisappear 中取消订阅:

NotificationCenter.default.removeObserver(self)

稍后在您的 ViewController 中:

@objc func showKeyboard(_ notification: NSNotification) {
    let info = notification.userInfo
    let rectValue = info![UIResponder.keyboardFrameEndUserInfoKey] as? NSValue
    if let keyboardSize = rectValue?.cgRectValue.size {
        bottomConstraint.constant = keyboardSize.height
        view.layoutIfNeeded()
    }
}

@objc func hideKeyboard(_ notification: Notification) {
    bottomConstraint.constant = 0
    view.layoutIfNeeded()
}

objective-C :

- (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)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear: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:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
    _bottomConstraint.constant = keyboardSize.height;
    [view layoutIfNeeded];
}

-(void)keyboardWillHide: (NSNotification *) notification {
    _bottomConstraint.constant = 0;
    [view layoutIfNeeded];
}