雨燕5

Question

我一直在尝试添加一些代码来在键盘出现时移动我的视图，但是，我在尝试将Objective-C示例转换为Swift时遇到了问题。我取得了一些进展，但我被困在一条特定的路线上。

这是我一直关注的两个教程/问题：

How to move content of UIViewController upwards as Keypad appears using Swift http://www.ioscreator.com/tutorials/move-view-when-keyboard-appears

以下是我目前的代码：

override func viewWillAppear(animated: Bool) {
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
}

override func viewWillDisappear(animated: Bool) {
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

func keyboardWillShow(notification: NSNotification) {
    var keyboardSize = notification.userInfo(valueForKey(UIKeyboardFrameBeginUserInfoKey))
    UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
    let frame = self.budgetEntryView.frame
    frame.origin.y = frame.origin.y - keyboardSize
    self.budgetEntryView.frame = frame
}

func keyboardWillHide(notification: NSNotification) {
    //
}

目前，我在这一行收到错误：

var keyboardSize = notification.userInfo(valueForKey(UIKeyboardFrameBeginUserInfoKey))

如果有人能让我知道这行代码应该是什么，我应该设法自己弄清楚其余部分。

Answer 1

您的行中存在一些问题

var keyboardSize = notification.userInfo(valueForKey(UIKeyboardFrameBeginUserInfoKey))

notification.userInfo返回可选字典[NSObject : AnyObject]?，所以在访问其值之前必须将其解包。
Objective-C NSDictionary映射到Swift本地词典，所以你必须这样做使用字典下标语法（dict[key]）来访问值。
该值必须转换为NSValue，以便您可以在其上调用CGRectValue。

所有这一切都可以通过可选分配，可选链接和可选的演员阵容：

if let userInfo = notification.userInfo {
   if let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
    let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
       // ...
   } else {
       // no UIKeyboardFrameBeginUserInfoKey entry in userInfo
   }
} else {
   // no userInfo dictionary in notification
}

或一步到位：

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

更新Swift 3.0.1（Xcode 8.1）：

if let userInfo = notification.userInfo {
    if let keyboardSize = userInfo[UIKeyboardFrameBeginUserInfoKey] as? CGRect {
        let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
        // ...
    } else {
        // no UIKeyboardFrameBeginUserInfoKey entry in userInfo
    }
} else {
    // no userInfo dictionary in notification
}

或一步到位：

if let keyboardSize = notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? CGRect {
    let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
    // ...
}

Answer 2

对于更少的代码，请考虑查看THIS

这对我很有帮助。您只需在视图控制器中包含视图约束并使用您添加的两个观察者。然后只使用以下方法（这里假设你移动一个tableView）

func keyboardWillShow(sender: NSNotification) {
        if let userInfo = sender.userInfo {
            if let keyboardHeight = userInfo[UIKeyboardFrameEndUserInfoKey]?.CGRectValue().size.height {
                tableViewBottomConstraint.constant = keyboardHeight
                UIView.animateWithDuration(0.25, animations: { () -> Void in
                    self.view.layoutIfNeeded()
                })
            }
        }
    }

和

func keyboardWillHide(sender: NSNotification) {
if let userInfo = sender.userInfo {
  if let keyboardHeight = userInfo[UIKeyboardFrameEndUserInfoKey]?.CGRectValue().size.height {
    tableViewBottomConstraint.constant = 0.0
    UIView.animateWithDuration(0.25, animations: { () -> Void in self.view.layoutIfNeeded() })
  }
} }

Answer 3

如果您使用的是故事板，而不是操纵视图本身，则可以利用自动布局。

（这是尼古拉斯答案的清理版）

设置通知中心，通知您键盘的外观和消失：

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)

}

并确保在您不再需要时删除观察员：

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

在故事板内，设置底部约束。创建该约束的出口：

并在显示或隐藏键盘时设置约束的常量属性：

func keyboardWillShow(notification: NSNotification) {
    guard let keyboardHeight = (notification.userInfo! as NSDictionary).objectForKey(UIKeyboardFrameBeginUserInfoKey)?.CGRectValue.size.height else {
        return
    }
    nameOfOutlet.constant = keyboardHeight
    view.layoutIfNeeded()
}

func keyboardWillHide(notification: NSNotification) {
    nameOfOutlet.constant = 0.0
    view.layoutIfNeeded()
}

现在，只要键盘出现或消失，自动布局就会处理所有事情。

Answer 4

Swift 2

func keyboardWasShown(notification:NSNotification) {
        guard let info:[NSObject:AnyObject] = notification.userInfo,
            let keyboardSize:CGSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size else { return }

        let insets:UIEdgeInsets = UIEdgeInsetsMake(self.scrollView.contentInset.top, 0.0, keyboardSize.height, 0.0)

        self.scrollView.contentInset = insets
        self.scrollView.scrollIndicatorInsets = insets
    }

Swift 3

func keyboardWasShown(notification:NSNotification) {
    guard let info:[AnyHashable:Any] = notification.userInfo,
        let keyboardSize:CGSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size else { return }

    let insets:UIEdgeInsets = UIEdgeInsets(top: self.scrollView.contentInset.top, left: 0.0, bottom: keyboardSize.height, right: 0.0)

    self.scrollView.contentInset = insets
    self.scrollView.scrollIndicatorInsets = insets
}

Answer 5

这帮助了我：https://developer.apple.com/library/ios/samplecode/UICatalog/Listings/Swift_UICatalog_TextViewController_swift.html

let userInfo = notification.userInfo!

let animationDuration: NSTimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as NSNumber).doubleValue
let keyboardScreenBeginFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as NSValue).CGRectValue()
let keyboardScreenEndFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as NSValue).CGRectValue()

Answer 6

您可以将这一行用于您的行

var keyboardSize:CGSize = userInfo.objectForKey(UIKeyboardFrameBeginUserInfoKey)!.CGRectValue().size

Answer 7

Swift 3：更新

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)

}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window)
}

Answer 8

雨燕5

用于基于键盘状态更新视图的最小代码。

具有布局限制

@IBOutlet weak var keyboardConstraint: NSLayoutConstraint!
let constraintMargin:CGFloat = 20

override func viewDidLoad() {
  super.viewDidLoad()
  NotificationCenter.default.addObserver(forName: UIResponder.keyboardDidShowNotification, object: nil, queue: nil) { (notification) in
    if let keyboardSize = notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? CGRect {
      self.keyboardConstraint.constant = keyboardSize.height + self.constraintMargin
    }
  }
  NotificationCenter.default.addObserver(forName: UIResponder.keyboardDidHideNotification, object: nil, queue: nil) { (notification) in
    self.keyboardConstraint.constant = self.constraintMargin
  }
}

使用ScrollView

@IBOutlet weak var scrollView: UIScrollView!
let constraintMargin: CGFloat = 20

override func viewDidLoad() {
  super.viewDidLoad()
  NotificationCenter.default.addObserver(forName: UIResponder.keyboardDidShowNotification, object: nil, queue: nil) { (notification) in
    if let keyboardSize = notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? CGRect {
      let insets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
      self.scrollView.contentInset = insets
      self.scrollView.scrollIndicatorInsets = insets
    }
  }
  NotificationCenter.default.addObserver(forName: UIResponder.keyboardDidHideNotification, object: nil, queue: nil) { (notification) in
    let insets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    self.scrollView.contentInset = insets
    self.scrollView.scrollIndicatorInsets = insets
  }
}

Answer 9

Swift 3.0

这是一个检索键盘大小并使用它来向上动画视图的示例。在我的情况下，当用户开始输入时，我正在向上移动包含我的UITextFields的UIView，这样他们就可以完成一个表单并仍然可以看到底部的提交按钮。

我为想要动画的视图的底部空间约束添加了一个插座，并将其命名为myViewsBottomSpaceConstraint：

@IBOutlet weak var myViewsBottomSpaceConstraint: NSLayoutConstraint!

然后我将以下代码添加到我的swift类中：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)

}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    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 userInfo = notification.userInfo as! [String: NSObject] as NSDictionary
    let keyboardFrame = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! CGRect
    let keyboardHeight = keyboardFrame.height
    myViewsBottomSpaceConstraint.constant = keyboardHeight
    view.layoutIfNeeded()
}

func keyboardWillHide(notification: NSNotification) {
    myViewsBottomSpaceConstraint.constant = 0.0
    view.layoutIfNeeded()
}

Answer 10

详细

xCode 8.2.1，swift 3

代码

KeyboardNotifications

import Foundation

class KeyboardNotifications {

    fileprivate var _isEnabled: Bool
    fileprivate var notifications:  [KeyboardNotificationsType]
    fileprivate var delegate: KeyboardNotificationsDelegate

    init(notifications: [KeyboardNotificationsType], delegate: KeyboardNotificationsDelegate) {
        _isEnabled = false
        self.notifications = notifications
        self.delegate = delegate
    }

    deinit {
        if isEnabled {
            isEnabled = false
        }
    }
}

// MARK: - enums

extension KeyboardNotifications {

    enum KeyboardNotificationsType {
        case willShow, willHide, didShow, didHide

        var selector: Selector {
            switch self {

            case .willShow:
                return #selector(KeyboardNotifications.keyboardWillShow(notification:))

            case .willHide:
                return #selector(KeyboardNotifications.keyboardWillHide(notification:))

            case .didShow:
                return #selector(KeyboardNotifications.keyboardDidShow(notification:))

            case .didHide:
                return #selector(KeyboardNotifications.keyboardDidHide(notification:))

            }
        }

        var notificationName: NSNotification.Name {
            switch self {

            case .willShow:
                return .UIKeyboardWillShow

            case .willHide:
                return .UIKeyboardWillHide

            case .didShow:
                return .UIKeyboardDidShow

            case .didHide:
                return .UIKeyboardDidHide
            }
        }
    }
}

// MARK: - isEnabled

extension KeyboardNotifications {

    private func addObserver(type: KeyboardNotificationsType) {
        NotificationCenter.default.addObserver(self, selector: type.selector, name: type.notificationName, object: nil)
        print("\(type.notificationName.rawValue) inited")
    }

    var isEnabled: Bool {
        set {
            if newValue {

                for notificaton in notifications {
                    addObserver(type: notificaton)
                }
            } else {
                NotificationCenter.default.removeObserver(self)
                print("Keyboard notifications deinited")
            }
            _isEnabled = newValue
        }

        get {
            return _isEnabled
        }
    }

}

// MARK: - Notification functions

extension KeyboardNotifications {

    @objc
    func keyboardWillShow(notification: NSNotification) {
        delegate.keyboardWillShow?(notification: notification)
    }

    @objc
    func keyboardWillHide(notification: NSNotification) {
        delegate.keyboardWillHide?(notification: notification)
    }

    @objc
    func keyboardDidShow(notification: NSNotification) {
        delegate.keyboardDidShow?(notification: notification)
    }

    @objc
    func keyboardDidHide(notification: NSNotification) {
        delegate.keyboardDidHide?(notification: notification)
    }
}

KeyboardNotificationsDelegate

import Foundation

@objc
protocol KeyboardNotificationsDelegate {

    @objc optional func keyboardWillShow(notification: NSNotification)
    @objc optional func keyboardWillHide(notification: NSNotification)
    @objc optional func keyboardDidShow(notification: NSNotification)
    @objc optional func keyboardDidHide(notification: NSNotification)
}

用法

 class ViewController: UIViewController {
      private var keyboardNotifications: KeyboardNotifications!
      override func viewDidLoad() {
           super.viewDidLoad()
           ...
            keyboardNotifications = KeyboardNotifications(notifications: [.willShow, .willHide, .didShow, .didHide], delegate: self)
      }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        keyboardNotifications.isEnabled = true
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        keyboardNotifications.isEnabled = false
    }

 }

 extension ViewController: KeyboardNotificationsDelegate {

    // If you don't need this func you can remove it
    func keyboardWillShow(notification: NSNotification) {
           ...
    }

    // If you don't need this func you can remove it
    func keyboardWillHide(notification: NSNotification) {
           ...
    }

    // If you don't need this func you can remove it
    func keyboardDidShow(notification: NSNotification) {
           ...
    }

    // If you don't need this func you can remove it
    func keyboardDidHide(notification: NSNotification) {
           ...
    }
}

完整样本

import UIKit

class ViewController: UIViewController {

    private var keyboardNotifications: KeyboardNotifications!
    private var textField = UITextField(frame: CGRect(x: 40, y: 40, width: 200, height: 30))

    override func viewDidLoad() {
        super.viewDidLoad()

        view.addSubview(textField)

        // when you will tap on view (background) the keyboard will hide
        // read about view.disableKeybordWhenTapped here: http://stackoverflow.com/a/42187286/4488252
        view.disableKeybordWhenTapped = true

        keyboardNotifications = KeyboardNotifications(notifications: [.willShow, .willHide, .didShow, .didHide], delegate: self)
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        keyboardNotifications.isEnabled = true
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        keyboardNotifications.isEnabled = false
    }

}

 extension ViewController: KeyboardNotificationsDelegate {

    // If you don't need this func you can remove it
    func keyboardWillShow(notification: NSNotification) {
        print("keyboardWillShow")
        let userInfo = notification.userInfo as! [String: NSObject]
        let keyboardFrame = userInfo[UIKeyboardFrameEndUserInfoKey] as! CGRect
        print("keyboardFrame: \(keyboardFrame)")
    }

    // If you don't need this func you can remove it
    func keyboardWillHide(notification: NSNotification) {
        print("keyboardWillHide")
    }

    // If you don't need this func you can remove it
    func keyboardDidShow(notification: NSNotification) {
        print("keyboardDidShow")
    }

    // If you don't need this func you can remove it
    func keyboardDidHide(notification: NSNotification) {
 print("keyboardDidHide")
    }
}

结果

日志

Answer 11

对于xamarin，您可以使用 C＃6

private void KeyboardWillChangeFrame(NSNotification notification)
{
        var keyboardSize = notification.UserInfo.ValueForKey(UIKeyboard.FrameEndUserInfoKey) as NSValue;
        if (keyboardSize != null)
        {
            var rect= keyboardSize.CGRectValue;
            //do your stuff here
        }
}

C＃7

  private void KeyboardWillChangeFrame(NSNotification notification)
   {
       if (!(notification.UserInfo.ValueForKey(UIKeyboard.FrameEndUserInfoKey) is NSValue keyboardSize)) return;
       var rect= keyboardSize.CGRectValue;
   }

Answer 12

在 Swift 4.2 中，您可以使用UIResponder.keyboardFrameEndUserInfoKey

guard let userInfo = notification.userInfo , let keyboardFrame:CGRect = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect  else { return  }```

从Swift中的userInfo获取键盘大小

12 个答案:

雨燕5

具有布局限制

使用ScrollView

详细

代码

用法

完整样本

结果

日志