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

对于Swift 3,我做了一个UIViewController子类,因为我需要在所有的视图控制器中恒定的行为。

class SomeClassVC: UIViewController {

  //MARK: - Lifecycle
  override func viewDidLoad() {
    super.viewDidLoad()

    addKeyboardObservers()
  }

  override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    removeKeyboardObservers()
  }

  //MARK: - Overrides
  override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    view.endEditing(true)
  }

  //MARK: - Help
  func addKeyboardObservers() {
    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)
  }

  func removeKeyboardObservers() {
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window)
  }

  func keyboardWillShow(notification: NSNotification) {
    let keyboardHeight = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.height
    UIView.animate(withDuration: 0.1, animations: { () -> Void in
      self.view.window?.frame.origin.y = -1 * keyboardHeight!
      self.view.layoutIfNeeded()
    })
  }

  func keyboardWillHide(notification: NSNotification) {
    UIView.animate(withDuration: 0.1, animations: { () -> Void in
      self.view.window?.frame.origin.y = 0
      self.view.layoutIfNeeded()
    })
  }

  func resignTextFieldFirstResponders() {
    for textField in self.view.subviews where textField is UITextField {
      textField.resignFirstResponder()
    }
  }

  func resignAllFirstResponders() {
      view.endEditing(true)
  }
}

其他回答

在这个线程中,一个流行的答案使用了以下代码:

func keyboardWillShow(sender: NSNotification) {
    self.view.frame.origin.y -= 150
}
func keyboardWillHide(sender: NSNotification) {
    self.view.frame.origin.y += 150
}

用一个静态量来抵消你的视图有一个明显的问题。它在一个设备上看起来很好,但在任何其他尺寸配置上看起来都很糟糕。您需要获取键盘高度并将其用作偏移值。

下面是一种适用于所有设备的解决方案,它可以处理用户在输入时隐藏预测文本字段的边缘情况。

解决方案

下面需要注意的是,我们将self.view.window作为对象参数传入。这将为我们提供来自键盘的数据,比如它的高度!

@IBOutlet weak var messageField: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: self.view.window)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: self.view.window)
}

func keyboardWillHide(sender: NSNotification) {
    let userInfo: [NSObject : AnyObject] = sender.userInfo!
    let keyboardSize: CGSize = userInfo[UIKeyboardFrameBeginUserInfoKey]!.CGRectValue.size
    self.view.frame.origin.y += keyboardSize.height
}

我们将使它在所有设备上看起来都很漂亮,并处理用户添加或删除预测文本字段的情况。

func keyboardWillShow(sender: NSNotification) {
    let userInfo: [NSObject : AnyObject] = sender.userInfo!
    let keyboardSize: CGSize = userInfo[UIKeyboardFrameBeginUserInfoKey]!.CGRectValue.size
    let offset: CGSize = userInfo[UIKeyboardFrameEndUserInfoKey]!.CGRectValue.size

    if keyboardSize.height == offset.height {
        UIView.animateWithDuration(0.1, animations: { () -> Void in
            self.view.frame.origin.y -= keyboardSize.height
        })
    } else {
        UIView.animateWithDuration(0.1, animations: { () -> Void in
            self.view.frame.origin.y += keyboardSize.height - offset.height
        })
    }
}

删除观察者

不要忘记在离开视图之前删除您的观察器,以防止传输不必要的消息。

override func viewWillDisappear(animated: Bool) {
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: self.view.window)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: self.view.window)
}

根据评论中的问题更新:

如果你有两个或更多的文本字段,你可以检查你的view.frame.origin.y是否为零。

func keyboardWillShow(sender: NSNotification) {
    let userInfo: [NSObject : AnyObject] = sender.userInfo!

    let keyboardSize: CGSize = userInfo[UIKeyboardFrameBeginUserInfoKey]!.CGRectValue.size
    let offset: CGSize = userInfo[UIKeyboardFrameEndUserInfoKey]!.CGRectValue.size

    if keyboardSize.height == offset.height {
        if self.view.frame.origin.y == 0 {
            UIView.animateWithDuration(0.1, animations: { () -> Void in
                self.view.frame.origin.y -= keyboardSize.height
            })
        }
    } else {
        UIView.animateWithDuration(0.1, animations: { () -> Void in
            self.view.frame.origin.y += keyboardSize.height - offset.height
        })
    }
     print(self.view.frame.origin.y)
}

我做了一个椰子荚来简化问题:

https://github.com/xtrinch/KeyboardLayoutHelper

如何使用:

做一个自动布局底部约束,在模块KeyboardLayoutHelper中给它一个KeyboardLayoutConstraint类,pod将做必要的工作来增加它,以适应出现和消失的键盘。关于如何使用它(我做了两个:一个scrollView内的textFields,和垂直居中的textFields与两个基本视图-登录和注册)的例子项目。

底部布局约束可以是容器视图,textField本身,任何你能想到的。

@Boris的解决方案非常好,但观点有时会被破坏。

为了实现完美的对齐,请使用下面的代码

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

功能:

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

And,

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

我已经阅读了答案,并通过以下代码行解决了我的问题:

class ViewController: UIViewController, UITextFieldDelegate {

  @IBOutlet weak var titleField: UITextField!
  @IBOutlet weak var priceField: UITextField!
  @IBOutlet weak var detailsField: UTtextField!

  override func viewDidLoad() {
   super.viewDidLoad()
// Do not to forget to set the delegate otherwise the textFieldShouldReturn(_:)
// won't work and the keyboard will never be hidden.
   priceField.delegate = self
   titleField.delegate = self
   detailsField.delegate = self

   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 textFieldShouldReturn(_ textField: UITextField) -> Bool {
      self.view.endEditing(true)
      return false
   }

 func keyboardWillShow(notification: NSNotification) {
   var translation:CGFloat = 0
   if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
     if detailsField.isEditing{
       translation = CGFloat(-keyboardSize.height)
     }else if priceField.isEditing{
       translation = CGFloat(-keyboardSize.height / 3.8)
     }
   }
    UIView.animate(withDuration: 0.2) {
   self.view.transform = CGAffineTransform(translationX: 0, y: translation)
    }
  }


 func keyboardWillHide(notification: NSNotification) {
    UIView.animate(withDuration: 0.2) {
     self.view.transform = CGAffineTransform(translationX: 0, y: 0)
    } 
  }
}

我有几个UITextFields,并希望视图移动不同取决于哪个textField被点击。

最简单的方法,甚至不需要任何代码:

下载KeyboardLayoutConstraint.swift并将文件添加(拖放)到你的项目中,如果你还没有使用Spring动画框架的话。 在你的故事板中,为视图或文本字段创建一个底部约束,选择约束(双击它),在标识检查器中,将其类从NSLayoutConstraint更改为KeyboardLayoutConstraint。 完成了!

物体会随着键盘同步自动移动。