如何获得键盘的高度？

7 回答

• 16

  In Swift:

  您可以通过订阅 UIKeyboardWillShowNotification 通知来获得键盘高度 . （假设你想知道它显示之前的高度） .

  像这样的东西：

  斯威夫特2

  NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
  

  斯威夫特3

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

  斯威夫特4

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

  然后你可以在 keyboardWillShow 函数中访问高度，如下所示：

  斯威夫特2

  func keyboardWillShow(notification: NSNotification) {
      let userInfo: NSDictionary = notification.userInfo!
      let keyboardFrame: NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
      let keyboardRectangle = keyboardFrame.CGRectValue()
      let keyboardHeight = keyboardRectangle.height
  }
  

  斯威夫特3

  @objc func keyboardWillShow(_ notification: Notification) {
      if let keyboardFrame: NSValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue {
          let keyboardRectangle = keyboardFrame.cgRectValue
          let keyboardHeight = keyboardRectangle.height
      }
  }
  

  斯威夫特4

  @objc func keyboardWillShow(_ notification: Notification) {
      if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
          let keyboardRectangle = keyboardFrame.cgRectValue
          let keyboardHeight = keyboardRectangle.height
      }
  

  回复于 2024-05-03T19:16:50+08:00
• 53

  Swift 3.0和Swift 4.1

  1-在 viewWillAppear 方法中注册通知：

  NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
  

  2-要求的方法：

  @objc func keyboardWillShow(notification: NSNotification) {
      if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
          let keyboardHeight = keyboardSize.height
          print(keyboardHeight)
      }
  }
  

  回复于 2024-05-03T19:16:50+08:00
• 1

  Swift 4 and Constraints

  在您的tableview中添加相对于底部安全区域的底部约束 . 在我的例子中，约束称为tableViewBottomLayoutConstraint .

  @IBOutlet weak var tableViewBottomLayoutConstraint: NSLayoutConstraint!
  
  override func viewWillAppear(_ animated: Bool) {
      super.viewWillAppear(animated)
  
      NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear(notification:)), name: .UIKeyboardWillShow, object: nil)
      NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear(notification:)), name: .UIKeyboardWillHide, object: nil)
  }
  
  override func viewWillDisappear(_ animated: Bool) {
      super.viewWillDisappear(animated)
  
      NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow , object: nil)
      NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide , object: nil)
  }
  
  @objc 
  func keyboardWillAppear(notification: NSNotification?) {
  
      guard let keyboardFrame = notification?.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue else {
          return
      }
  
      let keyboardHeight: CGFloat
      if #available(iOS 11.0, *) {
          keyboardHeight = keyboardFrame.cgRectValue.height - self.view.safeAreaInsets.bottom
      } else {
          keyboardHeight = keyboardFrame.cgRectValue.height
      }
  
      tableViewBottomLayoutConstraint.constant = keyboardHeight
  }
  
  @objc 
  func keyboardWillDisappear(notification: NSNotification?) {
      tableViewBottomLayoutConstraint.constant = 0.0
  }
  

  回复于 2024-05-03T19:16:50+08:00
• 129

  Update Swift 4.2

  private func setUpObserver() {
      NotificationCenter.default.addObserver(self, selector: .keyboardWillShow, name: UIResponder.keyboardWillShowNotification, object: nil)
  }
  

  选择器方法：

  @objc fileprivate func keyboardWillShow(notification:NSNotification) {
      if let keyboardRectValue = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
          let keyboardHeight = keyboardRectValue.height
      }
  }
  

  延期：

  private extension Selector {
      static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(notification:)) 
  }
  

  Update Swift 3.0

  private func setUpObserver() {
      NotificationCenter.default.addObserver(self, selector: .keyboardWillShow, name: .UIKeyboardWillShow, object: nil)
  }
  

  选择器方法：

  @objc fileprivate func keyboardWillShow(notification:NSNotification) {
      if let keyboardRectValue = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
          let keyboardHeight = keyboardRectValue.height
      }
  }
  

  延期：

  private extension Selector {
      static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(notification:)) 
  }
  

  Tip

  UIKeyboardDidShowNotification或UIKeyboardWillShowNotification可能会调用两次并获得不同的结果，这article解释了为什么调用两次 .

  In Swift 2.2

  Swift 2.2不推荐使用选择器的字符串，而是引入了新的语法： #selector .

  就像是：

  private func setUpObserver() {
  
      NSNotificationCenter.defaultCenter().addObserver(self, selector: .keyboardWillShow, name: UIKeyboardWillShowNotification, object: nil)
  }
  

  选择器方法：

  @objc private func keyboardWillShow(notification:NSNotification) {
  
      let userInfo:NSDictionary = notification.userInfo!
      let keyboardFrame:NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
      let keyboardRectangle = keyboardFrame.CGRectValue()
      let keyboardHeight = keyboardRectangle.height
      editorBottomCT.constant = keyboardHeight
  }
  

  延期：

  private extension Selector {
  
      static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(_:)) 
  }
  

  回复于 2024-05-03T19:16:50+08:00
• 10

  更短的版本：

  func keyboardWillShow(notification: NSNotification) {
  
          if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
              let keyboardHeight = keyboardSize.height
          }
  }
  

  回复于 2024-05-03T19:16:50+08:00
• 15

  Swift 4 .

  最简单的方法

  override func viewDidLoad() {
        super.viewDidLoad()
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
  }
  
  func keyboardWillShow(notification: NSNotification) {  
  
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
               let keyboardHeight : Int = Int(keyboardSize.height)
               print("keyboardHeight",keyboardHeight) 
        }
  
  }
  

  回复于 2024-05-03T19:16:50+08:00
• 2

  //步骤1： - 注册NotificationCenter

  ViewDidLoad() {
  
     self.yourtextfield.becomefirstresponder()
  
     // Register your Notification, To know When Key Board Appears.
      NotificationCenter.default.addObserver(self, selector: #selector(SelectVendorViewController.keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
  
     // Register your Notification, To know When Key Board Hides.
      NotificationCenter.default.addObserver(self, selector: #selector(SelectVendorViewController.keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
  }
  

  //步骤2： - 当键盘出现或隐藏时，将自动调用这些方法

  func keyboardWillShow(notification:NSNotification) {
          let userInfo:NSDictionary = notification.userInfo! as NSDictionary
          let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! NSValue
          let keyboardRectangle = keyboardFrame.cgRectValue
          let keyboardHeight = keyboardRectangle.height
          tblViewListData.frame.size.height = fltTblHeight-keyboardHeight
      }
  
      func keyboardWillHide(notification:NSNotification) {
          tblViewListData.frame.size.height = fltTblHeight
      }
  

  回复于 2024-05-03T19:16:50+08:00