快速出现键盘时移动文本字段

小编典典

快速出现键盘时移动文本字段

all

我正在使用 Swift 进行 iOS
编程，我正在使用此代码来移动UITextField，但它不起作用。我正确调用了该函数keyboardWillShow，但文本字段没有移动。我正在使用自动布局。

override func viewDidLoad() {
    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
}

deinit {
    NSNotificationCenter.defaultCenter().removeObserver(self);
}

func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        //let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)

        var frame = self.ChatField.frame
        frame.origin.y = frame.origin.y - keyboardSize.height + 167
        self.chatField.frame = frame
        println("asdasd")
    }
}

阅读 63

2022-06-04

共1个答案

小编典典

对现有答案有一些改进。

首先， UIKeyboardWillChangeFrameNotification
可能是最好的通知，因为它处理的变化不仅仅是显示/隐藏，而是由于键盘变化（语言、使用第 3
方键盘等）和旋转而引起的变化（但请注意下面的注释表明键盘将隐藏应该也可以处理支持硬件键盘连接）。

其次，可以从通知中提取动画参数，以确保动画正确组合在一起。

可能有一些选项可以更多地清理此代码，特别是如果您对强制解包字典代码感到满意。

 class MyViewController: UIViewController {

   // This constraint ties an element at zero points from the bottom layout guide
   @IBOutlet var keyboardHeightLayoutConstraint: NSLayoutConstraint?

   override func viewDidLoad() {
     super.viewDidLoad()
     NotificationCenter.default.addObserver(self,
       selector: #selector(self.keyboardNotification(notification:)),
       name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
   }

   deinit {
     NotificationCenter.default.removeObserver(self)
   }

   @objc func keyboardNotification(notification: NSNotification) {
     guard let userInfo = notification.userInfo else { return }

     let endFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
     let endFrameY = endFrame?.origin.y ?? 0
     let duration:TimeInterval = (userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
     let animationCurveRawNSN = userInfo[UIResponder.keyboardAnimationCurveUserInfoKey] as? NSNumber
     let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIView.AnimationOptions.curveEaseInOut.rawValue
     let animationCurve:UIView.AnimationOptions = UIView.AnimationOptions(rawValue: animationCurveRaw)

     if endFrameY >= UIScreen.main.bounds.size.height {
       self.keyboardHeightLayoutConstraint?.constant = 0.0
     } else {
       self.keyboardHeightLayoutConstraint?.constant = endFrame?.size.height ?? 0.0
     }

     UIView.animate(
       withDuration: duration,
       delay: TimeInterval(0),
       options: animationCurve,
       animations: { self.view.layoutIfNeeded() },
       completion: nil)
   }
}

2022-06-04