92

如何检测何时在应用程序中显示和隐藏键盘？

ios iphone iphone-sdk-3.0

— 用户198725878
source

— 凯西

166

在类的ViewDidLoad方法中，设置为侦听有关键盘的消息：

// Listen for keyboard appearances and disappearances
[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(keyboardDidShow:)
                                             name:UIKeyboardDidShowNotification
                                           object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardDidHide:)
                                             name:UIKeyboardDidHideNotification
                                           object:nil];

然后，在您指定的方法（在本例中为keyboardDidShow和keyboardDidHide）中，您可以对此做一些事情：

- (void)keyboardDidShow: (NSNotification *) notif{
    // Do something here
}

- (void)keyboardDidHide: (NSNotification *) notif{
    // Do something here
}

— 马修·弗雷德里克（Matthew Frederick）
source

如果通过字段制表符，则不起作用。想知道这将是什么解决方案，以及您是否甚至可以在实际的iPad上浏览？

— 2012年

@apprentice您的意思是如果您按Tab键就不会显示键盘？

— 马修·弗雷德里克

如果键盘下方的焦点仍然覆盖着字段，则视图将停留在选项卡上，因为仅在键盘向上滑动时才发出通知

— i-- 2012年

3

@apprentice您必须手动进行管理，根据每个文本字段的活动来滑动滚动视图，这与知道何时出现键盘是一个不同的问题。使您的视图控制器为UITextFieldDelegate，然后实现该textFieldShouldReturn:方法。您将获得textField刚刚输入的参数，您可以将其与自己的textFields进行比较并滚动，scrollView以便显示适当的textField。

— 马修·弗雷德里克

94

您可能只需要addObserver输入viewDidLoad。但是，“ addObserver进入” viewWillAppear和“ removeObserver进入” viewWillDisappear可以防止在更改视图时发生罕见的崩溃。

斯威夫特4.2

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear), name: UIResponder.keyboardWillHideNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear), name: UIResponder.keyboardWillShowNotification, object: nil)
}

@objc func keyboardWillAppear() {
    //Do something here
}

@objc func keyboardWillDisappear() {
    //Do something here
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self)
}

斯威夫特3和4

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear), name: Notification.Name.UIKeyboardWillHide, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear), name: Notification.Name.UIKeyboardWillShow, object: nil)
}

@objc func keyboardWillAppear() {
    //Do something here
}

@objc func keyboardWillDisappear() {
    //Do something here
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self)
}

较早的斯威夫特

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillAppear:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillDisappear:", name: UIKeyboardWillHideNotification, object: nil)
}

func keyboardWillAppear(notification: NSNotification){
    // Do something here
}

func keyboardWillDisappear(notification: NSNotification){
    // Do something here
}

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

— 埃斯卡鲁斯
source

9

如果删除viewWillDisappear ...上的观察者，则应将其添加到viewWillAppear中而不是viewDidLoad中。

— FouZ

没错，请随时编辑答案。我会接受

— Esqarrouth，2015年

@FouZ最好是这样删除观察者deinit：

deinit {         NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)         NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)     }

— Crashalot '16

在Swift 3中，上面的deinit代码块如下：

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

— Najmul Hasan博士

@Crashalot在关闭vc之前不会运行deinit。因此，如果您在此顶部显示另一个vc，它仍然会收到通知。我相信目的是仅在此vc可见时才收听此通知，因此对我来说，在viewdidappear上添加它并在viewdiddissapear上删除它似乎更好。

— Pochi

19

斯威夫特3：

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)

func keyboardWillShow(_ notification: NSNotification){
    // Do something here
}

func keyboardWillHide(_ notification: NSNotification){
    // Do something here
}

— 地臣
source

9

斯威夫特4：

  NotificationCenter.default.addObserver( self, selector: #selector(ControllerClassName.keyboardWillShow(_:)),
  name: Notification.Name.UIKeyboardWillShow,
  object: nil)
  NotificationCenter.default.addObserver(self, selector: #selector(ControllerClassName.keyboardWillHide(_:)),
  name: Notification.Name.UIKeyboardWillHide,
  object: nil)

接下来，添加方法以在对象的寿命结束时停止侦听通知：-

Then add the promised methods from above to the view controller:
deinit {
  NotificationCenter.default.removeObserver(self)
}
func adjustKeyboardShow(_ open: Bool, notification: Notification) {
  let userInfo = notification.userInfo ?? [:]
  let keyboardFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
  let height = (keyboardFrame.height + 20) * (open ? 1 : -1)
  scrollView.contentInset.bottom += height
  scrollView.scrollIndicatorInsets.bottom += height
}

@objc func keyboardWillShow(_ notification: Notification) {
  adjustKeyboardShow(true, notification: notification)
}
@objc func keyboardWillHide(_ notification: Notification) {
  adjustKeyboardShow(false, notification: notification)
}

— 古尔金德·辛格
source

的+=出现使插图越来越大。

— Wez

我认为AdjustKeyboardShow函数是一个非常完善的函数。谢谢。

— Hong开发人员

从Swift 5开始，通知名称为UIResponder.keyboardWillShowNotification和UIResponder.keyboardWillHideNotification，键盘信息键为UIResponder.keyboardFrameBeginUserInfoKey。

— CodeBrew

5

斯威夫特-4

override func viewWillAppear(_ animated: Bool) {
   super.viewWillAppear(animated)
   addKeyBoardListener()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self) //remove observer
}

func addKeyBoardListener() {
    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);
}

@objc func keyboardWillShow(_ notification: Notification) {

}

@objc func keyboardWillHide(_ notification: Notification) {

}

— 拉胡尔
source

4

请查看“文本，Web和编辑编程指南”的“ 管理键盘”部分，以获取有关跟踪显示或隐藏的键盘以及如何手动显示/关闭键盘的信息。

— 贾斯汀·斯帕夏（Justin Spahr-Summers）
source

4

您将需要注册2个键盘通知：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name: UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector (keyboardDidHide:) name: UIKeyboardDidHideNotification object:nil];

关于如何将TextField调整为键盘的好文章-http: //iosdevelopertips.com/user-interface/adjust-textfield-hidden-by-keyboard.html

— 克里斯·英特克斯
source

4

在Swift 4.2中，通知名称已移至其他名称空间。所以现在

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    addKeyboardListeners()
}


override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self)
}


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

@objc private extension WhateverTheClassNameIs {

    func keyboardWillShow(_ notification: Notification) {
        // Do something here.
    }

    func keyboardWillHide(_ notification: Notification) {
        // Do something here.
    }
}

— 塞博
source

3

迅捷5

上面的答案是正确的。尽管我更愿意创建一个帮助程序来包装notification's observers。

好处：

您不必每次处理键盘行为都重复一次。
您可以通过实现其他枚举值来扩展其他通知
当您必须在多个控制器中处理键盘时，此功能很有用。

样例代码：

extension KeyboardHelper {
    enum Animation {
        case keyboardWillShow
        case keyboardWillHide
    }

    typealias HandleBlock = (_ animation: Animation, _ keyboardFrame: CGRect, _ duration: TimeInterval) -> Void
}

final class KeyboardHelper {
    private let handleBlock: HandleBlock

    init(handleBlock: @escaping HandleBlock) {
        self.handleBlock = handleBlock
        setupNotification()
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    private func setupNotification() {
        _ = NotificationCenter.default
            .addObserver(forName: UIResponder.keyboardWillShowNotification, object: nil, queue: .main) { [weak self] notification in
                self?.handle(animation: .keyboardWillShow, notification: notification)
            }

        _ = NotificationCenter.default
            .addObserver(forName: UIResponder.keyboardWillHideNotification, object: nil, queue: .main) { [weak self] notification in
                self?.handle(animation: .keyboardWillHide, notification: notification)
            }
    }

    private func handle(animation: Animation, notification: Notification) {
        guard let userInfo = notification.userInfo,
            let keyboardFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue,
            let duration = userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double
        else { return }

        handleBlock(animation, keyboardFrame, duration)
    }
}

如何使用：

private var keyboardHelper: KeyboardHelper?
...

override func viewDidLoad() {
   ...
   keyboardHelper = KeyboardHelper { [unowned self] animation, keyboardFrame, duration in
        switch animation {
        case .keyboardWillShow:
            print("keyboard will show")
        case .keyboardWillHide:
            print("keyboard will hide")
        }
    }

}

— nahung89
source

2

斯威夫特4 -dd 20 october 2017

override func viewDidLoad() {
    [..]

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear(_:)), name: Notification.Name.UIKeyboardWillHide, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear(_:)), name: Notification.Name.UIKeyboardWillShow, object: nil)
}

@objc func keyboardWillAppear(_ notification: NSNotification) {
    if let userInfo = notification.userInfo, 
       let keyboardFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue).cgRectValue {
           let inset = keyboardFrame.height // if scrollView is not aligned to bottom of screen, subtract offset
           scrollView.contentInset.bottom = inset
           scrollView.scrollIndicatorInsets.bottom = inset
    }
}

@objc func keyboardWillDisappear(_ notification: NSNotification) {
    scrollView.contentInset.bottom = 0
    scrollView.scrollIndicatorInsets.bottom = 0
}

deinit {
    NotificationCenter.default.removeObserver(self)
}

— dOM
source

1

如果您的UITextField键盘数大于1，并且需要在键盘出现或消失时（或之前）执行某些操作，则可以实施此方法。

添加UITextFieldDelegate到您的课程。分配整数计数器，假设：

NSInteger editCounter;

将此计数器设置为零viewDidLoad。然后，实现textFieldShouldBeginEditing并textFieldShouldEndEditing委托方法。

在第一个中，将1添加到editCounter。如果editCounter的值变为1-这表示将出现键盘（如果返回YES）。如果editCounter> 1-这意味着键盘已经可见，并且另一个UITextField保持焦点。

在textFieldShouldEndEditing从editCounter减去1。如果您得到零-键盘将被关闭，否则它将保留在屏幕上。

— 用户名
source

0

您可以使用KBKeyboardObserver库。它包含一些示例，并提供了简单的界面。

— kam800
source

0

这里有一个CocoaPods可以方便观察NSNotificationCentr键盘的可见性：https : //github.com/levantAJ/Keyhi

pod 'Keyhi'

— 泰乐
source

0

所以啊，这才是真正的答案。

import Combine


class MrEnvironmentObject {
    /// Bind into yr SwiftUI views
    @Published public var isKeyboardShowing: Bool = false

    /// Keep 'em from deallocatin'
    var subscribers: [AnyCancellable]? = nil

    /// Adds certain Combine subscribers that will handle updating the
    ///  `isKeyboardShowing` property 
    ///
    /// - Parameter host: the UIHostingController of your views. 
    func setupSubscribers<V: View>(
        host: inout UIHostingController<V>
    ) {
        subscribers = [
            NotificationCenter
                .default
                .publisher(for: UIResponder.keyboardWillShowNotification)
                .sink { [weak self] _ in
                    self?.isKeyboardShowing = true
                },
            NotificationCenter
                .default
                .publisher(for: UIResponder.keyboardWillHideNotification)
                .sink { [weak self, weak host] _ in
                    self?.isKeyboardShowing = false
                    // Hidden gem, ask me how I know:
                    UIAccessibility.post(
                        notification: .layoutChanged, 
                        argument: host
                    )
                },
            // ...
            Profit
                .sink { [weak self] profit in profit() },
        ]
    }
}

— 鳞片状的
source

如何检测何时显示和隐藏键盘

斯威夫特4.2

斯威夫特3和4

较早的斯威夫特

迅捷5

好处：

样例代码：

如何使用：