Set-Up Scroll Selection on this View Controller

func createScrollSelection(withOffset offsetMultiplier: CGFloat = 70, 
                           usingStyle style: [ScrollSelection.Style] = ScrollSelection.Style.defaultStyle) -> ScrollSelection

• withOffset offsetMultiplier
  • Distance between each button selection
  • Default Value: 70
• usingStyle style
  • Scroll Selection Style. Use ScrollSelection.Style.defaultStyle for default implementation or remove this parameter
  • Default Value: ScrollSelection.Style.defaultStyle
  • Refer to Style for the various style information

An instance of Scroll Selection that is already set up

In your viewDidLoad function,

override func viewDidLoad() {
    super.viewDidLoad()
    
    // Default implementation
    scrollSelection = createScrollSelection() 

    // Custom implementation
    scrollSelection = createScrollSelection(withOffset: 70, usingStyle: ScrollSelection.Style.defaultStyle) 
}

Update bar buttons with Scroll Selection

func updateBarButtons(barButtonSide direction: ScrollSelection.Direction = .all)

Call this function whenever a change is made to the navigation bar buttons

• barButtonSide direction
  • .left corresponds to the left bar buttons, .right corresponds to the right bar buttons, .all updates all buttons.
  • Default Value: .all
  • Refer to Direction for the various direction information

After updating left bar button items,

scrollSelection.updateBarButtons(barButtonSide: .left)

Update ScrollSelection when the scrollview scrolls

func didScroll()

Updates scroll selection by highlighting or removing highlights on corresponding buttons

To be called in scrollViewDidScroll function that is part of UIScrollViewDelegate

extension ViewController: UIScrollViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        scrollSelection.didScroll()
    }
}

Update ScrollSelection when user stops dragging scrollView

func didEndDragging()

Called when scrollView is released (ends dragging) and thus, scroll selection will select the corresponding bar button

To be called in scrollViewDidEndDragging function that is part of UIScrollViewDelegate

extension ViewController: UIScrollViewDelegate {
    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        scrollSelection.didEndDragging()
    }
}

Update ScrollSelection once the scrollView stops decelerating

func didEndDecelerating()

Called when scrollView is ends deceerating and thus, scroll selection will reset to original state

To be called in scrollViewDidEndDecelerating function that is part of UIScrollViewDelegate

extension ViewController: UIScrollViewDelegate {
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        scrollSelection.didEndDecelerating()
    }
}

Y-Axis offset between selecting buttons

var offsetMultiplier: CGFloat!

Should be automatically set in by init or the UIViewController Implementation

Target UIScrollView for Scroll Selection

var scrollView: UIScrollView?

Should be automatically set in by init or the UIViewController Implementation

Scroll Selection will ignore all scrollViews except for the targetted one.

scrollSelection.scrollView = myScrollView

Haptic feedback styles

var hapticStyle: HapticsStyle = .variableIncreasing

It uses .variableIncreasing as default value.

Refer to HapticsStyle for the various styles

scrollSelection.hapticStyle = .variableIncreasing

Current scroll selection style

var style: [Style]!

Should be automatically set in by init or the UIViewController Implementation.

Refer to Scroll Selection Styles for the various styles

// Using the default style
scrollSelection.style = ScrollSelection.Style.defaultStyle 

// Using a custom style
scrollSelection.style = [.circularHighlight(using: .systemRed, expands: true)]

Changes the Button tint color during Scroll Selection

public static func highlight(using color: UIColor = UIColor.systemBlue.withAlphaComponent(0.7)) -> Style

• using color
  • Color to change to
  • Default Value: .systemBlue with alpha of 0.7

A scroll selection style

Adds a circular highlight/background to the button that is being selected

public static func circularHighlight(using color: UIColor = .systemGray4,
                                     expands: Bool = true, 
                                     fades: Bool = true) -> Style

• using color
  • Color of highlight
  • Default Value: .systemGray4 with alpha of 0.7
• expands
  • If true, circular highlights will expand radially to show emphasis on the button as the user scrolls up. Otherwise, it will stay static and the highlight will not expand.
• fades
  • If true, circular highlight background will fade as the user scrolls up. Otherwise, it will jump from one to another, without fading.

A scroll selection style

Normal Haptic Style

case normal

Normal corresponds to UISelectionFeedbackGenerator().selectionChanged(). A more subtle haptic style.

Default style, feedback becomes more pronounced as user scrolls up

case variableIncreasing

First Button -> Last Button
Weak         -> Strong

Haptic feedback becomes less pronounced as user scrolls up

case variableDecreasing

First Button -> Last Button
Strong       -> Weak

Update Left Bar Buttons

public static let left: Direction = Direction(rawValue: 1 << 0)

Update Right Bar Buttons

public static let right: Direction = Direction(rawValue: 1 << 1)

Update Both Left and Right Bar Buttons

public static let all: Direction = [.left, .right]

Activate Scroll Selection

func activate()

Deactivate Scroll Selection

func deactivate()