110 lines
4.2 KiB
Swift
110 lines
4.2 KiB
Swift
//
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// ScrollingViewController.swift
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// MVMCoreUI
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//
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// Created by Scott Pfeil on 3/12/20.
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// Copyright © 2020 Verizon Wireless. All rights reserved.
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//
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import Foundation
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open class ScrollingViewController: ViewController {
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public var dismissKeyboardTapGesture: UITapGestureRecognizer?
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@IBOutlet public var scrollView: UIScrollView!
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public var contentView: UIView?
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public var contentWidthConstraint: NSLayoutConstraint?
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private var keyboardNotificationsAdded = false
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private var keyboardIsShowing = false
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private var preKeyboardContentInset: UIEdgeInsets?
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public init(with scrollView: UIScrollView) {
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self.scrollView = scrollView
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super.init(nibName: nil, bundle: nil)
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}
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required public init?(coder: NSCoder) {
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super.init(coder: coder)
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}
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public override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
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super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
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}
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// MARK: - View Life Cycle
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open override func viewDidLoad() {
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super.viewDidLoad()
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// Adds the tap gesture to dismiss the keyboard.
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dismissKeyboardTapGesture = UITapGestureRecognizer(target: self, action: #selector(dismissFieldInput(sender:)))
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view.addGestureRecognizer(dismissKeyboardTapGesture!)
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dismissKeyboardTapGesture?.isEnabled = false
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scrollView.alwaysBounceVertical = false
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scrollView.delegate = self
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}
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open override func updateViewConstraints() {
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super.updateViewConstraints()
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// Sets the width of the content to the width of the screen.
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contentWidthConstraint?.constant = view.bounds.width - scrollView.contentInset.left - scrollView.contentInset.right
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}
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open override func viewDidLayoutSubviews() {
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super.viewDidLayoutSubviews()
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view.setNeedsUpdateConstraints()
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view.layoutSubviews()
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}
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open override func viewWillAppear(_ animated: Bool) {
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super.viewWillAppear(animated)
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registerForKeyboardNotifications()
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}
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// MARK: - Keyboard Handling
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open func registerForKeyboardNotifications() {
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if !keyboardNotificationsAdded {
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keyboardNotificationsAdded = true
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NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
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NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
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}
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}
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open func unregisterForKeyboardNotifications() {
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if keyboardNotificationsAdded {
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NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
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NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
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keyboardNotificationsAdded = false
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}
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}
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@objc open func keyboardWillShow(notification: Notification) {
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// Stores the current scroll insets if the keyboard was hidden.
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if !keyboardIsShowing {
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preKeyboardContentInset = scrollView.contentInset
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}
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keyboardIsShowing = true
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// Enables the tap gesture.
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dismissKeyboardTapGesture?.isEnabled = true
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MVMCoreUIUtility.setScrollViewInsetForKeyboardShow(notification, scrollView: scrollView, viewController: self) { [weak self] () -> CGRect in
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return self?.rectToScrollToWhenKeyboardPopsUp() ?? .zero
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}
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}
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@objc open func keyboardWillBeHidden(notification: Notification) {
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keyboardIsShowing = false
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// Disables the tap gesture.
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dismissKeyboardTapGesture?.isEnabled = false
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MVMCoreUIUtility.setScrollViewInsetForKeyboardHide(notification, scrollView: scrollView, viewController: self, contentInset: preKeyboardContentInset ?? scrollView.contentInset)
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}
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open func rectToScrollToWhenKeyboardPopsUp() -> CGRect? {
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guard let field = selectedField,
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let parent = selectedField?.superview else { return nil }
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return scrollView.convert(field.frame, from: parent)
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}
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}
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