Move view with keyboard using swift 3 - ios

Question

I have an app that has a text field on the lower half of the view and I have a navigation controller bottom of page.
How would I go about moving the view upwards while typing so I can see what i'm typing and then moving it back down to its original place when the keyboard disappears?
I don't want to move navigation controller

Answer 1

You have to observe changes in keyboard frame and act accordingly to show your uiview (uitextfield, uitextview etc.) above the keyboard.
NotificationCenter Apple documentation:
https://developer.apple.com/documentation/foundation/notificationcenter
Other answers at StackOverflow: How to make a UITextField move up when keyboard is present?
Here is a quick example of a view controller:
import UIKit
class ExampleViewController: UIViewController {
// MARK: - Properties
#IBOutlet weak var exampleTextView1: UITextView!
#IBOutlet weak var exampleTextView2: UITextView!
#IBOutlet weak var exampleTextView1BottomConstraint: NSLayoutConstraint!
#IBOutlet weak var exampleTextView2BottomConstraint: NSLayoutConstraint!
var exampleTextView1BottomConstraintInitialConstant: CGFloat!
var exampleTextView2BottomConstraintInitialConstant: CGFloat!
var keyboardVisibilityObservers: [NSObjectProtocol] = []
// MARK: - View lifecycle
override func viewDidLoad() {
super.viewDidLoad()
exampleTextView1BottomConstraintInitialConstant = exampleTextView1BottomConstraint.constant
exampleTextView2BottomConstraintInitialConstant = exampleTextView2BottomConstraint.constant
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// Add observers for text view 1
keyboardVisibilityObservers.append(createShowKeyboardObserver(keyboardTrigger: exampleTextView1, distance: 10.0, constraint: exampleTextView1BottomConstraint))
keyboardVisibilityObservers.append(createHideKeyboardObserver(keyboardTrigger: exampleTextView1, constraint: exampleTextView1BottomConstraint, initialConstraintConstant: exampleTextView1BottomConstraintInitialConstant))
// Add observers for text view 2
keyboardVisibilityObservers.append(createShowKeyboardObserver(keyboardTrigger: exampleTextView2, distance: 10.0, constraint: exampleTextView2BottomConstraint))
keyboardVisibilityObservers.append(createHideKeyboardObserver(keyboardTrigger: exampleTextView2, constraint: exampleTextView2BottomConstraint, initialConstraintConstant: exampleTextView2BottomConstraintInitialConstant))
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
removeAllKeyboardVisibilityNotificationObservers()
}
// MARK: - Keyboard event handling
private func createShowKeyboardObserver(keyboardTrigger: UIView, distance: CGFloat, constraint: NSLayoutConstraint) -> NSObjectProtocol {
return NotificationCenter.default.addObserver(forName: .UIKeyboardWillShow, object: nil, queue: nil) { (notification) in
if let userInfo = notification.userInfo,
let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
// Get animation duration and curve from user info dictionary
let duration: TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIViewAnimationOptions.curveEaseInOut.rawValue
let animationCurve: UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
let originYAxisOfKeyboardTrigger = keyboardTrigger.convert(keyboardTrigger.bounds.origin, to: self.view).y
let preferredOriginYAxisOfKeyboardTrigger = endFrame.origin.y - distance - keyboardTrigger.bounds.height
constraint.constant = constraint.constant - (originYAxisOfKeyboardTrigger - preferredOriginYAxisOfKeyboardTrigger)
// Animate changes
UIView.animate(withDuration: duration,
delay: TimeInterval(0),
options: animationCurve,
animations: { self.view.layoutIfNeeded() },
completion: nil)
}
}
}
private func createHideKeyboardObserver(keyboardTrigger: UIView, constraint: NSLayoutConstraint, initialConstraintConstant: CGFloat) -> NSObjectProtocol {
return NotificationCenter.default.addObserver(forName: .UIKeyboardWillHide, object: nil, queue: nil) { (notification) in
if let userInfo = notification.userInfo {
// Get animation duration and curve from user info dictionary
let duration: TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIViewAnimationOptions.curveEaseInOut.rawValue
let animationCurve: UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
constraint.constant = initialConstraintConstant
// Animate changes
UIView.animate(withDuration: duration,
delay: TimeInterval(0),
options: animationCurve,
animations: { self.view.layoutIfNeeded() },
completion: nil)
}
}
}
private func removeAllKeyboardVisibilityNotificationObservers() {
keyboardVisibilityObservers.forEach { (observer) in
NotificationCenter.default.removeObserver(observer)
}
keyboardVisibilityObservers.removeAll()
}
}