[ios] How to get height of Keyboard?

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?

Swift 4 .

Simplest Method

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) 
      }

}

Update Swift 4.2

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

selector method:

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

extension:

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)
}

selector method:

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

extension:

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

Tip

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

In Swift 2.2

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

Something like:

private func setUpObserver() {

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

selector method:

@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:

    private extension Selector {

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

I uses below code,

override func viewDidLoad() {
    super.viewDidLoad()
    self.registerObservers()
}

func registerObservers(){

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)

}

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

@objc func keyboardWillAppear(notification: Notification){
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        let keyboardHeight = keyboardRectangle.height
        self.view.transform = CGAffineTransform(translationX: 0, y: -keyboardHeight)
    }
}

@objc func keyboardWillHide(notification: Notification){
        self.view.transform = .identity
}

Swift 4 and Constraints

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

Swift 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)")
            }
        }
    }

Shorter version here:

func keyboardWillShow(notification: NSNotification) {

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

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

ViewController Extension + Struct

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

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

call the function inside viewDidLoad()

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 textfield and
-it will push all view to above keyboard when keyboard appear.
-you could also used dismissKeyboard() when ever you need it

Swift 3.0 and Swift 4.1

1- Register the notification in the viewWillAppear method:

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

2- Method to be called:

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

// Step 1 :- Register 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)
}

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

    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
    }

The method by ZAFAR007 updated for Swift 5 in Xcode 10

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)
    }

}