键盘快速出现时如何移动文本框?

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我使用Swift进行iOS编程,我正在使用这段代码来移动它UITextField,但它不起作用。我keyboardWillShow正确调用该函数,但文本字段不移动。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")
    }
}
提问于
用户回答回答于

可能有更多的选项可以清理这些代码

Swift 3.x / 4.x

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()
    // Note that SO highlighting makes the new selector syntax (#selector()) look
    // like a comment but it isn't one
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardNotification(notification:)), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)
}

deinit {
    NotificationCenter.default.removeObserver(self)
}

@objc func keyboardNotification(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
        let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
        let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
        let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIViewAnimationOptions.curveEaseInOut.rawValue
        let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
        if (endFrame?.origin.y)! >= 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)
    }
}

Swift 2.x

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()
    // Note that SO highlighting makes the new selector syntax (#selector()) look
    // like a comment but it isn't one
    NSNotificationCenter.defaultCenter().addObserver(self,
      selector: #selector(self.keyboardNotification(_:)),
      name: UIKeyboardWillChangeFrameNotification,
      object: nil)
}

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

func keyboardNotification(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as?     NSValue)?.CGRectValue()
        let duration:NSTimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
        let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
        let animationCurveRaw = animationCurveRawNSN?.unsignedLongValue ?? UIViewAnimationOptions.CurveEaseInOut.rawValue
        let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
        if endFrame?.origin.y >= UIScreen.mainScreen().bounds.size.height {
            self.keyboardHeightLayoutConstraint?.constant = 0.0
        } else {
            self.keyboardHeightLayoutConstraint?.constant = endFrame?.size.height ?? 0.0
        }
        UIView.animateWithDuration(duration,
            delay: NSTimeInterval(0),
            options: animationCurve,
            animations: { self.view.layoutIfNeeded() },
            completion: nil)
    }
}
用户回答回答于

如果你使用自动布局,我假设你已将底部空间设置为超视图约束。如果是这样的话,你只需要更新约束的值。这是你如何做一点动画。

func keyboardWasShown(notification: NSNotification) {
    let info = notification.userInfo!
    let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()

    UIView.animateWithDuration(0.1, animations: { () -> Void in
        self.bottomConstraint.constant = keyboardFrame.size.height + 20
    })
}

硬编码20仅用于弹出键盘上方的文本框。否则,键盘的上边距和文本区域的下边距将会触碰。

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