我有一个应用,它在视图的下半部分有一个文本框。 这意味着当我在文本框中输入时,键盘会覆盖文本框。

我如何在打字时向上移动视图,这样我就可以看到我键入的内容,然后在键盘消失时将它移回原来的位置?

我到处都看了,但所有的解似乎都在Obj-C中,我还不能完全转换。

任何帮助都将不胜感激。


当前回答

对我有用

override func viewDidLoad() {

        super.viewDidLoad()

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

 var isScroll = false


@objc func keyboardWillShow(sender: NSNotification) {
    if( !isScroll  ){
        self.view.frame.origin.y -= 150
        isScroll = true
    }
}
@objc func keyboardWillHide(sender: NSNotification) {
    if( isScroll  ){
        self.view.frame.origin.y += 150
        isScroll = false
    }
}

其他回答

这个实现(Swift 4)将给你的行为最接近Android的默认行为。Ie:当活动文本域在键盘下时,将视图向上移动,当用户切换到另一个视图时,无需关闭键盘。记住调用settextfielddelegate()。

public class DelegateProxy: NSObject, UITextFieldDelegate {

  private static let instance = DelegateProxies()

  weak var activeTextField: UITextField?
  var offset: CGFloat = 0
  weak var vc: UIViewController?
  var keyboardHeight: CGFloat = 0

  public static func getDelegate(root: UIViewController) -> DelegateProxies {
    instance.vc = root
    return instance
  }

  public static func getDelegate() -> DelegateProxies {
    return instance
  }

  public func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    return true
  }


  public func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {

    self.activeTextField = textField

    let globalPointY: CGFloat = (textField.superview?.convert(textField.frame.origin, to: nil).y ?? CGFloat(0)) + textField.frame.height


    offset = UIScreen.main.bounds.height - globalPointY

    if keyboardHeight > 0 {
        vc?.moveViewUp(offsetFromKeyboard: keyboardHeight - offset)
    }

    return true
  }
}


extension UIViewController {

  private func setTextFieldDelegates(parentView: UIView) {
    for child in parentView.subviews {
        setTextFieldDelegates(parentView: child)
        (child as? UITextField)?.delegate = DelegateProxies.getDelegate(root: self)
    }
  }

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

  func unregisterAutoResizeOnKeyboard(){
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
  }

  @objc func keyboardWillShow(notification: NSNotification) {

    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
        let offsetFromKeyboard = keyboardSize.height - DelegateProxies.getDelegate().offset
        DelegateProxies.getDelegate().keyboardHeight = keyboardSize.height

        moveViewUp(offsetFromKeyboard: offsetFromKeyboard)
    }
  }

  func moveViewUp(offsetFromKeyboard: CGFloat){
    print("offset from keyboard: \(offsetFromKeyboard)")

    let moveOffset = offsetFromKeyboard + 8

    if offsetFromKeyboard > 0 {
        self.view.frame.origin.y = -moveOffset
    }

    if offsetFromKeyboard < 0 && view.frame.origin.y < 0 {
        self.view.frame.origin.y += -moveOffset
        if self.view.frame.origin.y > 0{
            self.view.frame.origin.y = 0
        }
    }
  }

  @objc func keyboardWillHide(notification: NSNotification) {
    self.view.frame.origin.y = 0
  }
}

我们对KeyboardWillHideNotification的定义做了一些改变。

此解决方案适用于Swift 4.2:

NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)


@objc func keyboardWillShow(_ notification:Notification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
        self.view.frame.origin.y -= keyboardSize.height
    }
}

@objc func keyboardWillHide(_ notification:Notification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        self.view.frame.origin.y += keyboardSize.height
    }
}

由于在Combine中没有如何做到这一点的答案,这里是我使用的方法。

我们创建一个发布者来监听通知,显示和隐藏。 为了显示,我们从通知userInfo中获取键盘帧,并检查当前活动响应器是否包含在其中。如果被覆盖,返回键盘帧高度。如果它没有被覆盖,返回0,我们不想移动帧。对于隐藏通知,我们简单地返回0。

private var keyboardHeightPublisher: AnyPublisher<CGFloat, Never> {
    Publishers.Merge(
        NotificationCenter.default
            .publisher(for: UIResponder.keyboardWillShowNotification)
            .compactMap { $0.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect }
            .map { $0.intersects(self.view.firstResponder!.frame) ? $0.height : 0 }
            .map { $0 * -1 },
        NotificationCenter.default
            .publisher(for: UIResponder.keyboardWillHideNotification)
            .map { _ in CGFloat(0) }
    ).eraseToAnyPublisher()
}

在viewDidLoad中,我们只需订阅发布者,相应地改变视图框架。

override func viewDidLoad() {
    super.viewDidLoad()

    keyboardHeightPublisher.sink{ [weak self] height in
        self?.view.frame.origin.y = height
    }.store(in: &cancelables)
}

编辑 小心!如果firstResponder在子视图中,你必须计算与整个屏幕相对应的帧,以检查它们是否相交。 例子:

let myViewGlobalFrame = myView.convert(myView.frame, to: parentView)

使用以下代码查看UITextField单击

func textFieldDidBeginEditing(textField: UITextField) {
    ViewUpanimateMoving(true, upValue: 100)
}
func textFieldDidEndEditing(textField: UITextField) {
    ViewUpanimateMoving(false, upValue: 100)
}
func ViewUpanimateMoving (up:Bool, upValue :CGFloat){
    var durationMovement:NSTimeInterval = 0.3
    var movement:CGFloat = ( up ? -upValue : upValue)
    UIView.beginAnimations( "animateView", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(durationMovement)
    self.view.frame = CGRectOffset(self.view.frame, 0,  movement)
    UIView.commitAnimations()
}

类似于@Boris的回答,但在Swift 5中:

override func viewDidLoad() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}

@IBAction func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        if self.view.frame.origin.y == 0 {
            self.view.frame.origin.y -= keyboardSize.height
        }
    }
}

@IBAction func keyboardWillHide(notification: NSNotification) {
    if self.view.frame.origin.y != 0 {
        self.view.frame.origin.y = 0
    }
}