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damienlaughton/BaseViewController

Created May 19, 2019 15:06
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  1. damienlaughton created this gist May 19, 2019.
    114 changes: 114 additions & 0 deletions BaseViewController
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,114 @@
    //
    // BaseViewController.swift
    // uitextfieldobscura
    //
    // Created by Damien Laughton on 19/05/2019.
    // Copyright © 2019 Damien Laughton. All rights reserved.
    //

    import Foundation
    import UIKit

    class BaseViewController: UIViewController {

    @IBOutlet weak var scrollViewBottomConstraint: NSLayoutConstraint?

    }

    /// Adjust any scroll view bottom constraint when the keyboard
    /// appears or disappears
    extension BaseViewController {

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

    startObservingKeyboardNotifications()
    }

    override func viewWillDisappear(_ animated: Bool) {

    stopObservingKeyboardNotifications()

    super.viewWillDisappear(animated)
    }

    /// Add the observors for keyboard showing / hiding
    func startObservingKeyboardNotifications() {
    NotificationCenter.default.addObserver(
    self,
    selector: #selector(keyboardWillShow),
    name: UIResponder.keyboardWillShowNotification,
    object: nil
    )

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

    /// Remove the observors for keyboard showing / hiding
    func stopObservingKeyboardNotifications() {
    NotificationCenter.default.removeObserver(
    self,
    name: UIResponder.keyboardWillShowNotification,
    object: nil
    )

    NotificationCenter.default.removeObserver(
    self,
    name: UIResponder.keyboardWillHideNotification,
    object: nil
    )
    }

    /// When the keyboard shows, get it's height and adjust the constant
    /// of the scroll view bottom constraint, setting it to the height.
    @objc func keyboardWillShow(_ notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
    let keyboardRectangle = keyboardFrame.cgRectValue

    scrollViewBottomConstraint?.constant = keyboardRectangle.height
    }
    }

    /// When the keyboard hides, reset the constant
    /// of the scroll view bottom constraint to zero.
    @objc func keyboardWillHide(_ notification: Notification) {

    scrollViewBottomConstraint?.constant = 0.0
    }
    }

    /// Dismiss keyboard when tap on view
    extension BaseViewController {

    override func viewDidLoad() {
    super.viewDidLoad()

    self.hideKeyboardWhenTappedAround()
    }

    /// Hide the keyboard when the user taps somewhere ele on the screen
    func hideKeyboardWhenTappedAround() {
    let tap = UITapGestureRecognizer(target: self, action: #selector(BaseViewController.dismissKeyboard))
    tap.cancelsTouchesInView = false
    view.addGestureRecognizer(tap)
    }

    /// Hides the keyboard
    @objc func dismissKeyboard() {
    view.endEditing(true)
    }
    }

    /// Hides the keyboard when its 'Return' key is tapped
    extension BaseViewController: UITextFieldDelegate {

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    return true
    }
    }