Move button when keyboard appears swift - swift

Question

In a UIViewController I have several text fields and a button is on the bottom of the UIViewController.
For the button, I have set a bottom constraint with a constant of 0.
Then I made an outlet from the bottom constraint to the UIViewController.
When I run my code, the button does not move upwards. I have seen suggestions on stackoverflow that I should add UIScrollView, but that means, I would have to delete all the objects on the UIViewController, put the UIScrollView and then put my objects on the UIVIewController again.
#IBOutlet weak var bottomConstraint: NSLayoutConstraint!
// When tapping outside of the keyboard, close the keyboard down
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.view.endEditing(true)
}
// Stop Editing on Return Key Tap. textField parameter refers to any textfield within the view
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
// When keyboard is about to show assign the height of the keyboard to bottomConstraint.constant of our button so that it will move up
func keyboardWillShow(notification: NSNotification) {
if let userInfo = notification.userInfo {
if let keyboardSize: CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
bottomConstraint.constant = keyboardSize.size.height
view.setNeedsLayout()
}
}
}
// When keyboard is hidden, move the button to the bottom of the view
func keyboardWillHide(notification: NSNotification) {
bottomConstraint.constant = 0.0
view.setNeedsLayout()
}

Answer 1

The typical way to address this would be to move the keyboard with code like this:
in ViewController class:
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
if view.frame.origin.y == 0{
let height = keyboardSize.height
self.view.frame.origin.y += height
}
}
}
func keyboardWillHide(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
if view.frame.origin.y != 0 {
let height = keyboardSize.height
self.view.frame.origin.y -= height
}
}
}
in ViewDidLoad method:
NotificationCenter.default.addObserver(self, selector: Selector("keyboardWillShow:"), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: Selector("keyboardWillHide:"), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
Please Read This:
The way you are trying to solve your problem is not allowed. In the code above, if you change view to your button variable name, the button will shoot up and then fall back down. This is because Auto Layout and Programmatic layout do not work together, it is one or the other. The way you fix this is by programmatically creating that button (with CGRect), then using the code above to move only that button on keyboard press. (Do that by changing view to your button variable name.
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if view.frame.origin.y == 0{
let height = keyboardSize.height
self.yourBtn.frame.origin.y += height
}
}
}
func keyboardWillHide(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if view.frame.origin.y != 0 {
let height = keyboardSize.height
self.yourBtn.frame.origin.y -= height
}
}
}
To programmatically create the button you would use code similar to this:
myButton.frame = CGRect(...)

Answer 2

Complimentary to Ryan's answer above, this can be done all with auto-layout and no need for frames and CGRect.
Swift 5
In your view, constrain your button as you normally would but add a reference to the constraint for modification when the keyboard hides/shows:
var bottomButtonConstraint = NSLayoutConstraint()
bottomButtonConstraint = yourButton.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor, constant: -12)
bottomButtonConstraint.isActive = true
In your ViewController's viewDidLoad():
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
Also in your ViewController:
#objc private func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
self.yourCustomView.bottomButtonConstraint.constant -= keyboardSize.height
}
}
#objc private func keyboardWillHide(notification: NSNotification) {
self.yourCustomView.bottomButtonConstraint.constant = -12
}

Answer 3

You need add(viewDidLoad) observers to call your functions:
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillShow), name: UIKeyboardDidShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillHide), name: UIKeyboardDidHideNotification, object: nil)

Answer 4

Consider using this pod: https://cocoapods.org/pods/IQKeyboardManager
In AppDelegate.swift, just import IQKeyboardManagerSwift framework and enable IQKeyboardManager.
import IQKeyboardManagerSwift
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
IQKeyboardManager.shared.enable = true
return true
}
}