ios 如何获得键盘的高度？

How to get height of Keyboard?

提问by Lachtan

The height of a keyboard on varying iOS devices is different. Does anybody know how I can get height of a device's keyboard programmatically?

不同 iOS 设备上的键盘高度不同。有人知道如何以编程方式获取设备键盘的高度吗？

回答by roc

In Swift:

在斯威夫特：

You can get the keyboard height by subscribing to the UIKeyboardWillShowNotificationnotification. (Assuming you want to know what the height will be before it's shown).

您可以通过订阅UIKeyboardWillShowNotification通知来获取键盘高度。（假设您想在显示之前知道高度是多少）。

Something like this:

像这样的东西：

Swift 2

斯威夫特 2

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

Swift 3

斯威夫特 3

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

Swift 4

斯威夫特 4

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

Then you can access the height in keyboardWillShowfunction like these:

然后你可以访问keyboardWillShow函数中的高度，如下所示：

Swift 2

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
}

Swift 3

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
    }
}

Swift 4

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
    }
}

回答by fs_tigre

Swift 3.0 and Swift 4.1

Swift 3.0 和 Swift 4.1

1- Register the notification in the viewWillAppearmethod:

1- 在viewWillAppear方法中注册通知：

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

2- Method to be called:

2-要调用的方法：

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

回答by Eduardo Irias

Swift 4 and Constraints

Swift 4 和约束

To your tableview add a bottom constraint relative to the bottom safe area. In my case the constraint is called tableViewBottomLayoutConstraint.

向您的 tableview 添加一个相对于底部安全区域的底部约束。在我的情况下，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
}

回答by Jesse

Update Swift 4.2

更新 Swift 4.2

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

selector method:

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
    }
}

extension:

延期：

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

Update Swift 3.0

更新 Swift 3.0

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

selector method:

选择器方法：

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

extension:

延期：

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

Tip

提示

UIKeyboardDidShowNotification or UIKeyboardWillShowNotification might called twice and got different result, this articleexplained why called twice.

UIKeyboardDidShowNotification 或 UIKeyboardWillShowNotification 可能会调用两次并得到不同的结果，本文解释了为什么会调用两次。

In Swift 2.2

在 Swift 2.2 中

Swift 2.2 deprecates using strings for selectors and instead introduces new syntax: #selector.

Swift 2.2 不赞成使用字符串作为选择器，而是引入了新的语法：#selector.

Something like:

就像是：

private func setUpObserver() {

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

selector method:

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
}

extension:

延期：

    private extension Selector {

    static let keyboardWillShow = #selector(YourViewController.keyboardWillShow(_:)) 
}

回答by Alessign

Shorter version here:

更短的版本在这里：

func keyboardWillShow(notification: NSNotification) {

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

回答by ZAFAR007

Swift 4.

斯威夫特 4。

Simplest Method

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) 
      }

}

回答by Vivek

Swift 5

斯威夫特 5

override func viewDidLoad() {
    //  Registering for keyboard notification.
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
}


/*  UIKeyboardWillShowNotification. */
    @objc internal func keyboardWillShow(_ notification : Notification?) -> Void {

        var _kbSize:CGSize!

        if let info = notification?.userInfo {

            let frameEndUserInfoKey = UIResponder.keyboardFrameEndUserInfoKey

            //  Getting UIKeyboardSize.
            if let kbFrame = info[frameEndUserInfoKey] as? CGRect {

                let screenSize = UIScreen.main.bounds

                //Calculating actual keyboard displayed size, keyboard frame may be different when hardware keyboard is attached (Bug ID: #469) (Bug ID: #381)
                let intersectRect = kbFrame.intersection(screenSize)

                if intersectRect.isNull {
                    _kbSize = CGSize(width: screenSize.size.width, height: 0)
                } else {
                    _kbSize = intersectRect.size
                }
                print("Your Keyboard Size \(_kbSize)")
            }
        }
    }

回答by P.T.Dog94

The method by ZAFAR007 updated for Swift 5 in Xcode 10

ZAFAR007 在 Xcode 10 中为 Swift 5 更新的方法

override func viewDidLoad() {
    super.viewDidLoad()

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

}




@objc func keyboardWillShow(notification: NSNotification) {

    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        let keyboardHeight : Int = Int(keyboardSize.height)
        print("keyboardHeight",keyboardHeight)
    }

}

回答by Nrv

// Step 1 :- Register NotificationCenter

// 步骤 1 :- 注册通知中心

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)
}

// Step 2 :- These Methods will be called Automatically when Keyboard appears Or Hides

// 步骤 2 :- 当键盘出现或隐藏时这些方法将被自动调用

    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
    }

回答by Muhammad Asyraf

I had to do this. this is a bit of hackery. not suggested.
but i found this very helpful
I made extension and struct

我不得不这样做。这有点骇人听闻。不建议。
但我发现这很有帮助
我做了扩展和结构

ViewController Extension + Struct

ViewController 扩展 + 结构

import UIKit
struct viewGlobal{
    static var bottomConstraint : NSLayoutConstraint = NSLayoutConstraint()
}

extension UIViewController{ //keyboardHandler
 func hideKeyboardWhenTappedAround() {
    let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(dismissKeyboard))
    tap.cancelsTouchesInView = false
    view.addGestureRecognizer(tap)
 }
 func listenerKeyboard(bottomConstraint: NSLayoutConstraint) {
    viewGlobal.bottomConstraint = bottomConstraint
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
    // Register your Notification, To know When Key Board Hides.
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
 }
 //Dismiss Keyboard
 @objc func dismissKeyboard() {
    view.endEditing(true)
 }
 @objc func keyboardWillShow(notification:NSNotification) {
    let userInfo:NSDictionary = notification.userInfo! as NSDictionary
    let keyboardFrame:NSValue = userInfo.value(forKey: UIResponder.keyboardFrameEndUserInfoKey) as! NSValue
    let keyboardRectangle = keyboardFrame.cgRectValue
    let keyboardHeight = keyboardRectangle.height
    UIView.animate(withDuration: 0.5){
        viewGlobal.bottomConstraint.constant = keyboardHeight
    }
 }

 @objc func keyboardWillHide(notification:NSNotification) {
    UIView.animate(withDuration: 0.5){
        viewGlobal.bottomConstraint.constant = 0
    }
 }
}

Usage:
get most bottom constraint

用法：
获取最底约束

@IBOutlet weak var bottomConstraint: NSLayoutConstraint! // default 0

call the function inside viewDidLoad()

在viewDidLoad() 中调用函数

override func viewDidLoad() {
    super.viewDidLoad()

    hideKeyboardWhenTappedAround()
    listenerKeyboard(bottomConstraint: bottomConstraint)

    // Do any additional setup after loading the view.
}

Hope this help.
-you keyboard will now auto close when user tap outside of textfieldand
-it will push all view to above keyboardwhen keyboard appear.
-you could also used dismissKeyboard()when ever you need it

希望这有帮助。
-当用户点击文本字段外时，您的键盘现在将自动关闭，并且
-当键盘出现时，它将把所有视图推送到键盘上方。
- 你也可以在需要的时候使用dismissKeyboard()