XLPagerTabStrip

https://github.com/xmartlabs/xlpagertabstrip
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XLPagerTabStrip is an iOS container view controller that enables easy navigation between multiple...
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### Install XLPagerTabStrip with Carthage

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Add this line to your Cartfile to include the library in your project.

```ogdl
github "xmartlabs/XLPagerTabStrip" ~> 9.0
```

--------------------------------

### Install XLPagerTabStrip with CocoaPods

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Add this line to your Podfile to include the library in your project.

```ruby
pod 'XLPagerTabStrip', '~> 9.0'
```

--------------------------------

### Install XLPagerTabStrip with Carthage

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Add XLPagerTabStrip using Carthage as an alternative dependency manager.

```ogdl
# Cartfile
github "xmartlabs/XLPagerTabStrip" ~> 9.0
```

--------------------------------

### Implement BarPagerTabStripViewController Data Source

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Provide the view controllers for the pager using the viewControllers(for:) method. This example maps image names to ImageViewController instances, each providing its IndicatorInfo.

```swift
override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
    let images = ["photo1", "photo2", "photo3", "photo4", "photo5"]

    return images.map {
        ImageViewController(imageName: $0, itemInfo: IndicatorInfo(title: $0))
    }
}
```

--------------------------------

### Install XLPagerTabStrip with CocoaPods

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Add XLPagerTabStrip to your iOS project using CocoaPods for dependency management.

```ruby
# Podfile
pod 'XLPagerTabStrip', '~> 9.0'
```

--------------------------------

### Implement TwitterPagerTabStripViewController Data Source

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Define the view controllers for the Twitter-style pager. This example creates instances of TweetListViewController and SearchViewController, each with an associated item info string.

```swift
override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
    let homeVC = TweetListViewController(itemInfo: "Home")
    let mentionsVC = TweetListViewController(itemInfo: "Mentions")
    let searchVC = SearchViewController(itemInfo: "Search")

    return [homeVC, mentionsVC, searchVC]
}
```

--------------------------------

### Install XLPagerTabStrip with Swift Package Manager

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Add XLPagerTabStrip using SPM for modern Swift projects. This can be done via Xcode or directly in your Package.swift file.

```swift
// In Xcode: File > Swift Packages > Add Package Dependency
// URL: https://github.com/xmartlabs/XLPagerTabStrip.git
// Version: Up to Next Major with "9.0.0"

// Or in Package.swift
dependencies: [
    .package(url: "https://github.com/xmartlabs/XLPagerTabStrip.git", from: "9.0.0")
]
```

--------------------------------

### Implement PagerTabStripDelegate and PagerTabStripIsProgressiveDelegate

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Implement delegate methods to receive callbacks when the indicator updates, allowing custom UI responses to page changes. This example shows how to set up the delegate, datasource, and pager behaviour, and implement methods for both progressive and non-progressive indicator updates.

```swift
import XLPagerTabStrip

class DelegateExampleViewController: PagerTabStripViewController, PagerTabStripDataSource, PagerTabStripIsProgressiveDelegate {

    @IBOutlet weak var customIndicatorView: UIView!
    @IBOutlet weak var pageLabel: UILabel!

    override func viewDidLoad() {
        delegate = self
        datasource = self
        pagerBehaviour = .progressive(skipIntermediateViewControllers: true, elasticIndicatorLimit: true)

        super.viewDidLoad()
    }

    // MARK: - PagerTabStripDataSource

    func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        return [
            PageViewController(itemInfo: "Page 1"),
            PageViewController(itemInfo: "Page 2"),
            PageViewController(itemInfo: "Page 3")
        ]
    }

    // MARK: - PagerTabStripIsProgressiveDelegate

    // Called continuously during swipe for progressive behavior
    func updateIndicator(for viewController: PagerTabStripViewController,
                         fromIndex: Int,
                         toIndex: Int,
                         withProgressPercentage progressPercentage: CGFloat,
                         indexWasChanged: Bool) {

        // Update custom indicator position based on progress
        let totalWidth = view.bounds.width
        let segmentWidth = totalWidth / CGFloat(self.viewControllers.count)

        let fromPosition = segmentWidth * CGFloat(fromIndex) + segmentWidth / 2
        let toPosition = segmentWidth * CGFloat(toIndex) + segmentWidth / 2

        let currentPosition = fromPosition + (toPosition - fromPosition) * progressPercentage
        customIndicatorView.center.x = currentPosition

        // Update label when page actually changes
        if indexWasChanged {
            pageLabel.text = "Page \(currentIndex + 1) of \(self.viewControllers.count)"
        }

        // Fade effect during transition
        customIndicatorView.alpha = 0.5 + (progressPercentage * 0.5)
    }

    // MARK: - PagerTabStripDelegate (for non-progressive behavior)

    // Called once when page change completes (common behavior)
    func updateIndicator(for viewController: PagerTabStripViewController,
                         fromIndex: Int,
                         toIndex: Int) {

        pageLabel.text = "Moved from \(fromIndex) to \(toIndex)"

        UIView.animate(withDuration: 0.3) {
            let segmentWidth = self.view.bounds.width / CGFloat(self.viewControllers.count)
            self.customIndicatorView.center.x = segmentWidth * CGFloat(toIndex) + segmentWidth / 2
        }
    }
}

```

--------------------------------

### Create IndicatorInfo Instances

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

The IndicatorInfo structure holds metadata for tab indicators, supporting titles, images, highlighted images, accessibility labels, and custom user info. Examples demonstrate various ways to initialize IndicatorInfo.

```swift
import XLPagerTabStrip

// Simple title-based indicator
let titleIndicator = IndicatorInfo(title: "Home")

// Image-based indicator for icon tabs
let imageIndicator = IndicatorInfo(
    image: UIImage(named: "home_icon"),
    highlightedImage: UIImage(named: "home_icon_selected"),
    userInfo: ["id": "home"])

// Combined title and image indicator
let combinedIndicator = IndicatorInfo(
    title: "Settings",
    image: UIImage(named: "settings_icon"),
    highlightedImage: UIImage(named: "settings_icon_selected"),
    userInfo: nil
)

// Using string literal (ExpressibleByStringLiteral conformance)
let literalIndicator: IndicatorInfo = "Dashboard"

// With custom accessibility label
let accessibleIndicator = IndicatorInfo(
    title: "Notifications",
    accessibilityLabel: "View your notifications",
    image: UIImage(named: "bell_icon"),
    highlightedImage: nil,
    userInfo: nil
)
```

--------------------------------

### Implement IndicatorInfoProvider Protocol

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Child view controllers embedded in a pager must conform to IndicatorInfoProvider to supply tab indicator metadata. This example shows a basic implementation for a ProfileViewController.

```swift
import XLPagerTabStrip

class ProfileViewController: UIViewController, IndicatorInfoProvider {

    var itemInfo: IndicatorInfo = "Profile"

    init(itemInfo: IndicatorInfo) {
        self.itemInfo = itemInfo
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white

        let label = UILabel()
        label.text = "Profile Content"
        label.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(label)

        NSLayoutConstraint.activate([
            label.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
    }

    // MARK: - IndicatorInfoProvider

    func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
        return itemInfo
    }
}
```

--------------------------------

### Dynamically Reload PagerTabStrip

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Reload the pager view with new child view controllers dynamically at runtime. This is useful for adding or removing tabs after the initial setup. Ensure `reloadPagerTabStripView()` is called to trigger the update.

```swift
import XLPagerTabStrip

class DynamicPagerViewController: ButtonBarPagerTabStripViewController {

    var tabConfigurations: [(title: String, type: String)] = [
        ("Home", "feed"),
        ("Popular", "popular"),
        ("Recent", "recent")
    ]

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.rightBarButtonItem = UIBarButtonItem(
            title: "Add Tab",
            style: .plain,
            target: self,
            action: #selector(addNewTab)
        )
    }

    @objc func addNewTab() {
        // Add new configuration
        let newIndex = tabConfigurations.count + 1
        tabConfigurations.append(("Tab \(newIndex)", "custom"))

        // Optionally change pager behavior during reload
        pagerBehaviour = .progressive(
            skipIntermediateViewControllers: true,
            elasticIndicatorLimit: true
        )

        // Trigger reload - this calls viewControllers(for:) again
        reloadPagerTabStripView()
    }

    func removeTab(at index: Int) {
        guard index < tabConfigurations.count else { return }
        tabConfigurations.remove(at: index)
        reloadPagerTabStripView()
    }

    func updateTabs(with newConfigs: [(title: String, type: String)]) {
        tabConfigurations = newConfigs
        reloadPagerTabStripView()
    }

    // MARK: - PagerTabStripDataSource

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        return tabConfigurations.map {
            ContentViewController(itemInfo: IndicatorInfo(title: $0.title), contentType: $0.type)
        }
    }
}

class ContentViewController: UIViewController, IndicatorInfoProvider {

    let itemInfo: IndicatorInfo
    let contentType: String

    init(itemInfo: IndicatorInfo, contentType: String) {
        self.itemInfo = itemInfo
        self.contentType = contentType
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
        return itemInfo
    }
}

```

--------------------------------

### Clone the repository

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Initial step to set up a local development environment by cloning the forked repository.

```bash
git clone git@github.com:<your-github-username>/XLPagerTabStrip.git
```

--------------------------------

### Create ImageViewController for Gallery

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

A custom UIViewController that displays an image and conforms to IndicatorInfoProvider. It initializes with an image name and IndicatorInfo, and sets up an ImageView in viewDidLoad.

```swift
class ImageViewController: UIViewController, IndicatorInfoProvider {

    let imageName: String
    let itemInfo: IndicatorInfo

    init(imageName: String, itemInfo: IndicatorInfo) {
        self.imageName = imageName
        self.itemInfo = itemInfo
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let imageView = UIImageView(image: UIImage(named: imageName))
        imageView.contentMode = .scaleAspectFit
        imageView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(imageView)

        NSLayoutConstraint.activate([
            imageView.topAnchor.constraint(equalTo: view.topAnchor),
            imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor)
        ])
    }

    func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
        return itemInfo
    }
}
```

--------------------------------

### Stage and commit changes

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Stages all local changes and commits them with a descriptive message.

```bash
git add .
git commit -m "Your commit message"
```

--------------------------------

### Present TwitterPagerTabStripViewController

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Demonstrates how to present a TwitterPagerTabStripViewController. It requires embedding the pager within a UINavigationController before presenting it.

```swift
let twitterPager = TimelineViewController()
let navController = UINavigationController(rootViewController: twitterPager)
present(navController, animated: true)
```

--------------------------------

### Implement IndicatorInfoProvider for Embedded View Controllers

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Conform to IndicatorInfoProvider and implement this method to provide title or image information for each embedded view controller's indicator.

```swift
class MyEmbeddedViewController: UITableViewController, IndicatorInfoProvider {

  func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
    return IndicatorInfo(title: "My Child title")
  }
}
```

--------------------------------

### ButtonBar Customization Settings

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Configuration properties for the ButtonBar style. Settings must be applied before viewDidLoad is called.

```swift

settings.style.buttonBarBackgroundColor: UIColor?
// buttonBar minimumInteritemSpacing value, note that button bar extends from UICollectionView
settings.style.buttonBarMinimumInteritemSpacing: CGFloat?
// buttonBar minimumLineSpacing value
settings.style.buttonBarMinimumLineSpacing: CGFloat?
// buttonBar flow layout left content inset value
settings.style.buttonBarLeftContentInset: CGFloat?
// buttonBar flow layout right content inset value
settings.style.buttonBarRightContentInset: CGFloat?

// selected bar view is created programmatically so it's important to set up the following 2 properties properly
settings.style.selectedBarBackgroundColor = UIColor.black
settings.style.selectedBarHeight: CGFloat = 5

// each buttonBar item is a UICollectionView cell of type ButtonBarViewCell
settings.style.buttonBarItemBackgroundColor: UIColor?
settings.style.buttonBarItemFont = UIFont.systemFont(ofSize: 18)
// helps to determine the cell width, it represent the space before and after the title label
settings.style.buttonBarItemLeftRightMargin: CGFloat = 8
settings.style.buttonBarItemTitleColor: UIColor?
// in case the barView items do not fill the screen width this property stretch the cells to fill the screen
settings.style.buttonBarItemsShouldFillAvailableWidth = true
// only used if button bar is created programmatically and not using storyboards or nib files as recommended.
public var buttonBarHeight: CGFloat?
```

```swift
override func viewDidLoad() {
   self.settings.style.selectedBarHeight = 2
   self.settings.style.selectedBarBackgroundColor = UIColor.white

   super.viewDidLoad()
}
```

--------------------------------

### Create a feature branch

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Creates and switches to a new branch based on the upstream master.

```bash
git checkout -b my-feature-name
```

--------------------------------

### Create a PagerTabStripViewController

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Define a custom pager controller by extending one of the built-in pager classes provided by the library.

```swift
import XLPagerTabStrip

class MyPagerTabStripName: ButtonBarPagerTabStripViewController {
  ..
}
```

--------------------------------

### Customize ButtonBarViewCell Configuration

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Override `configureCell` to add custom views like badges or modify existing elements such as image tint colors. Ensure any added subviews have a unique tag for easy removal.

```swift
import XLPagerTabStrip

class CustomCellPagerViewController: ButtonBarPagerTabStripViewController {

    override func viewDidLoad() {
        settings.style.buttonBarItemFont = .systemFont(ofSize: 14)
        settings.style.selectedBarHeight = 2

        super.viewDidLoad()
    }

    // Override to customize each cell
    override func configureCell(_ cell: ButtonBarViewCell, indicatorInfo: IndicatorInfo) {
        // Add badge or custom views
        if let userInfo = indicatorInfo.userInfo as? [String: Any],
           let badgeCount = userInfo["badge"] as? Int,
           badgeCount > 0 {

            let badgeLabel = UILabel()
            badgeLabel.text = "\(badgeCount)"
            badgeLabel.font = .systemFont(ofSize: 10, weight: .bold)
            badgeLabel.textColor = .white
            badgeLabel.backgroundColor = .red
            badgeLabel.textAlignment = .center
            badgeLabel.layer.cornerRadius = 8
            badgeLabel.layer.masksToBounds = true
            badgeLabel.frame = CGRect(x: cell.bounds.width - 20, y: 4, width: 16, height: 16)
            badgeLabel.tag = 999

            // Remove existing badge
            cell.viewWithTag(999)?.removeFromSuperview()
            cell.addSubview(badgeLabel)
        }

        // Custom image tinting
        cell.imageView.tintColor = .gray
    }

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        let inboxInfo = IndicatorInfo(
            title: "Inbox",
            image: UIImage(systemName: "envelope"),
            userInfo: ["badge": 5]
        )

        let sentInfo = IndicatorInfo(
            title: "Sent",
            image: UIImage(systemName: "paperplane"),
            userInfo: ["badge": 0]
        )

        let draftsInfo = IndicatorInfo(
            title: "Drafts",
            image: UIImage(systemName: "doc"),
            userInfo: ["badge": 2]
        )

        return [
            MailViewController(itemInfo: inboxInfo),
            MailViewController(itemInfo: sentInfo),
            MailViewController(itemInfo: draftsInfo)
        ]
    }
}

class MailViewController: UIViewController, IndicatorInfoProvider {
    let itemInfo: IndicatorInfo

    init(itemInfo: IndicatorInfo) {
        self.itemInfo = itemInfo
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) { fatalError() }

    func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
        return itemInfo
    }
}

```

--------------------------------

### Implement ButtonBarPagerTabStripViewController

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Configures a horizontally scrollable button bar with custom styles and progressive color changes. Settings must be applied before calling super.viewDidLoad().

```swift
import XLPagerTabStrip

class MainTabViewController: ButtonBarPagerTabStripViewController {

    override func viewDidLoad() {
        // Configure settings BEFORE calling super.viewDidLoad()
        settings.style.buttonBarBackgroundColor = .white
        settings.style.buttonBarItemBackgroundColor = .white
        settings.style.selectedBarBackgroundColor = UIColor(red: 37/255, green: 111/255, blue: 206/255, alpha: 1)
        settings.style.selectedBarHeight = 2.0
        settings.style.buttonBarItemFont = .boldSystemFont(ofSize: 14)
        settings.style.buttonBarItemTitleColor = .darkGray
        settings.style.buttonBarItemsShouldFillAvailableWidth = true
        settings.style.buttonBarMinimumLineSpacing = 0
        settings.style.buttonBarLeftContentInset = 0
        settings.style.buttonBarRightContentInset = 0

        // Configure progressive color change on swipe
        changeCurrentIndexProgressive = { (oldCell: ButtonBarViewCell?, newCell: ButtonBarViewCell?, progressPercentage: CGFloat, changeCurrentIndex: Bool, animated: Bool) in
            guard changeCurrentIndex else { return }

            oldCell?.label.textColor = .darkGray
            newCell?.label.textColor = UIColor(red: 37/255, green: 111/255, blue: 206/255, alpha: 1)
        }

        super.viewDidLoad()

        // Additional customization after viewDidLoad
        buttonBarView.selectedBar.backgroundColor = .systemBlue
        buttonBarView.backgroundColor = .white
    }

    // MARK: - PagerTabStripDataSource

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        let feedVC = FeedViewController(itemInfo: "FEED")
        let discoverVC = DiscoverViewController(itemInfo: "DISCOVER")
        let notificationsVC = NotificationsViewController(itemInfo: "NOTIFICATIONS")
        let profileVC = ProfileViewController(itemInfo: "PROFILE")

        return [feedVC, discoverVC, notificationsVC, profileVC]
    }
}
```

--------------------------------

### Programmatic Navigation with PagerTabStrip

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Navigate between child view controllers programmatically using index or view controller reference. Ensure navigation is possible before attempting to move.

```swift
import XLPagerTabStrip

class NavigablePagerViewController: ButtonBarPagerTabStripViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Add navigation buttons
        let prevButton = UIBarButtonItem(title: "Prev", style: .plain, target: self, action: #selector(goToPrevious))
        let nextButton = UIBarButtonItem(title: "Next", style: .plain, target: self, action: #selector(goToNext))
        navigationItem.leftBarButtonItem = prevButton
        navigationItem.rightBarButtonItem = nextButton
    }

    @objc func goToPrevious() {
        guard currentIndex > 0 else { return }

        // Navigate by index with animation
        moveToViewController(at: currentIndex - 1, animated: true)
    }

    @objc func goToNext() {
        guard currentIndex < viewControllers.count - 1 else { return }

        // Navigate by index with animation
        moveToViewController(at: currentIndex + 1, animated: true)
    }

    func jumpToTab(index: Int) {
        // Navigate without animation
        moveToViewController(at: index, animated: false)
    }

    func navigateToViewController(_ targetVC: UIViewController) {
        // Navigate by view controller reference
        moveTo(viewController: targetVC, animated: true)
    }

    // Check if navigation is possible
    func canNavigateTo(index: Int) -> Bool {
        return canMoveTo(index: index)
    }

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        return [
            ChildViewController(itemInfo: "First"),
            ChildViewController(itemInfo: "Second"),
            ChildViewController(itemInfo: "Third")
        ]
    }
}
```

--------------------------------

### Squash commits

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Interactive rebase to squash multiple commits into one before submission.

```bash
git rebase -i HEAD~6
```

--------------------------------

### Provide View Controllers for PagerTabStrip

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Override this method to return the view controllers that will be embedded within the PagerTabStrip.

```swift
override public func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
  return [MyEmbeddedViewController(), MySecondEmbeddedViewController()]
}
```

--------------------------------

### Configure PagerTabStrip Behaviour

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Set the pager behavior to .progressive for smooth indicator movement or .common for discrete jumps. Progressive behavior allows skipping intermediate view controllers and enables elastic indicator limits.

```swift
import XLPagerTabStrip

class CustomPagerViewController: ButtonBarPagerTabStripViewController {

    override func viewDidLoad() {
        // Progressive: Indicator moves smoothly during swipe
        // - skipIntermediateViewControllers: Skip middle tabs when tapping distant tab
        // - elasticIndicatorLimit: Allow indicator to stretch at edges
        pagerBehaviour = .progressive(
            skipIntermediateViewControllers: true,
            elasticIndicatorLimit: true
        )

        // OR Common: Indicator jumps to new position at midpoint
        // pagerBehaviour = .common(skipIntermediateViewControllers: true)

        super.viewDidLoad()
    }

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        return [
            ChildViewController(itemInfo: "Tab 1"),
            ChildViewController(itemInfo: "Tab 2"),
            ChildViewController(itemInfo: "Tab 3")
        ]
    }
}
```

```swift
// Check behavior properties
let behaviour = PagerTabStripBehaviour.progressive(
    skipIntermediateViewControllers: true,
    elasticIndicatorLimit: false
)

print(behaviour.isProgressiveIndicator)      // true
print(behaviour.skipIntermediateViewControllers)  // true
print(behaviour.isElasticIndicatorLimit)     // false
```

--------------------------------

### Bar Type Customization

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Configuration settings for the standard Bar type.

```swift
settings.style.barBackgroundColor: UIColor?
settings.style.selectedBarBackgroundColor: UIColor?
// barHeight is only set up when the bar is created programmatically and not using storyboards or xib files as recommended.
settings.style.barHeight: CGFloat = 5
```

--------------------------------

### PagerTabStrip Protocols

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Protocols for handling indicator updates. These are typically handled by the library but can be overridden if needed.

```swift
public protocol PagerTabStripDelegate: class {

    func updateIndicator(for viewController: PagerTabStripViewController, fromIndex: Int, toIndex: Int)
}

public protocol PagerTabStripIsProgressiveDelegate : PagerTabStripDelegate {

    func updateIndicator(for viewController: PagerTabStripViewController, fromIndex: Int, toIndex: Int, withProgressPercentage progressPercentage: CGFloat, indexWasChanged: Bool)
}
```

--------------------------------

### Add upstream remote

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Configures the original repository as an upstream remote to keep the fork synchronized.

```bash
git remote add upstream git@github.com:xmartlabs/XLPagerTabStrip.git
```

--------------------------------

### Twitter Type Customization

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Configuration settings for the Twitter-style bar.

```swift
settings.style.dotColor = UIColor(white: 1, alpha: 0.4)
settings.style.selectedDotColor = UIColor.white
settings.style.portraitTitleFont = UIFont.systemFont(ofSize: 18)
settings.style.landscapeTitleFont = UIFont.systemFont(ofSize: 15)
settings.style.titleColor = UIColor.white
```

--------------------------------

### Implement SegmentedPagerTabStripViewController

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Uses a native UISegmentedControl for navigation. Child view controllers must conform to IndicatorInfoProvider to provide tab information.

```swift
import XLPagerTabStrip

class SettingsViewController: SegmentedPagerTabStripViewController {

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        // Configure segmented control color before view loads
        settings.style.segmentedControlColor = .systemBlue
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // The segmentedControl is automatically set as navigationItem.titleView
        // Or connect via IBOutlet for custom placement
    }

    // MARK: - PagerTabStripDataSource

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        let generalVC = GeneralSettingsViewController(itemInfo: "General")
        let privacyVC = PrivacySettingsViewController(itemInfo: "Privacy")
        let accountVC = AccountSettingsViewController(itemInfo: "Account")

        return [generalVC, privacyVC, accountVC]
    }
}

// Child view controller example
class GeneralSettingsViewController: UITableViewController, IndicatorInfoProvider {

    let itemInfo: IndicatorInfo

    init(itemInfo: IndicatorInfo) {
        self.itemInfo = itemInfo
        super.init(style: .grouped)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
        return itemInfo
    }
}
```

--------------------------------

### Update and rebase branch

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Ensures the feature branch is up to date with upstream changes using a rebase.

```bash
git pull --rebase upstream master
```

--------------------------------

### Programmatic Navigation API

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Methods provided by PagerTabStripViewController to programmatically change the visible child view controller.

```APIDOC
## Programmatic Navigation Methods

### Description
These methods allow developers to programmatically switch the active child view controller within a PagerTabStripViewController.

### Methods
- **moveToViewController(at index: Int)**: Moves to the child view controller at the specified index.
- **moveToViewController(at index: Int, animated: Bool)**: Moves to the child view controller at the specified index with an optional animation.
- **moveTo(viewController: UIViewController)**: Moves to the specified child view controller instance.
- **moveTo(viewController: UIViewController, animated: Bool)**: Moves to the specified child view controller instance with an optional animation.
```

--------------------------------

### Configure BarPagerTabStripViewController Appearance

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Customize the appearance of the sliding bar indicator for BarPagerTabStripViewController. Configure bar background color, selected bar color, and bar height before calling super.viewDidLoad().

```swift
settings.style.barBackgroundColor = UIColor.lightGray.withAlphaComponent(0.3)
settings.style.selectedBarBackgroundColor = .white
settings.style.barHeight = 4
```

--------------------------------

### Default PagerTabStripBehaviour Values

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Shows the default pager behaviour configurations for different PagerTabStripViewController types.

```swift
// Twitter Type
PagerTabStripBehaviour.common(skipIntermediateViewControllers: true)
// Segmented Type
PagerTabStripBehaviour.common(skipIntermediateViewControllers: true)
// Bar Type
PagerTabStripBehaviour.progressive(skipIntermediateViewControllers: true, elasticIndicatorLimit: true)
// ButtonBar Type
PagerTabStripBehaviour.progressive(skipIntermediateViewControllers: true, elasticIndicatorLimit: true)
```

--------------------------------

### Segmented Type Customization

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Configuration settings for the Segmented control style.

```swift
settings.style.segmentedControlColor: UIColor?
```

--------------------------------

### Programmatically change child view controllers

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Use these methods within PagerTabStripViewController to navigate between child view controllers.

```swift
func moveToViewController(at index: Int)
func moveToViewController(at index: Int, animated: Bool)
func moveTo(viewController: UIViewController)
func moveTo(viewController: UIViewController, animated: Bool)
```

--------------------------------

### Configure TwitterPagerTabStripViewController Appearance

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Customize the appearance for TwitterPagerTabStripViewController, including dot color, selected dot color, and title fonts for portrait and landscape orientations. Also configure the navigation bar appearance.

```swift
settings.style.dotColor = UIColor(white: 1, alpha: 0.4)
settings.style.selectedDotColor = .white
settings.style.portraitTitleFont = UIFont.systemFont(ofSize: 18, weight: .semibold)
settings.style.landscapeTitleFont = UIFont.systemFont(ofSize: 15, weight: .semibold)
settings.style.titleColor = .white

navigationController?.navigationBar.barTintColor = UIColor(red: 29/255, green: 161/255, blue: 242/255, alpha: 1)
navigationController?.navigationBar.isTranslucent = false
```

--------------------------------

### Synchronize master branch

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/CONTRIBUTING.md

Commands to update the local master branch from the upstream repository.

```bash
git checkout master
git pull upstream master
git push origin master
```

--------------------------------

### Define PagerTabStrip Behaviour

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Choose how the pager indicator should update during transitions by setting the pagerBehaviour property.

```swift
public var pagerBehaviour: PagerTabStripBehaviour
```

--------------------------------

### ButtonBar Cell Update Callbacks

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Properties to define how cells update when the selected index changes. Use changeCurrentIndexProgressive for progressive updates.

```swift
public var changeCurrentIndex: ((oldCell: ButtonBarViewCell?, newCell: ButtonBarViewCell?, animated: Bool) -> Void)?
public var changeCurrentIndexProgressive: ((oldCell: ButtonBarViewCell?, newCell: ButtonBarViewCell?, progressPercentage: CGFloat, changeCurrentIndex: Bool, animated: Bool) -> Void)?
```

```swift
changeCurrentIndexProgressive = { (oldCell: ButtonBarViewCell?, newCell: ButtonBarViewCell?, progressPercentage: CGFloat, changeCurrentIndex: Bool, animated: Bool) -> Void in
    guard changeCurrentIndex == true else { return }

    oldCell?.label.textColor = UIColor(white: 1, alpha: 0.6)
    newCell?.label.textColor = UIColor.white

    if animated {
        UIView.animate(withDuration: 0.1, animations: { () -> Void in
            newCell?.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)
            oldCell?.transform = CGAffineTransform(scaleX: 0.8, y: 0.8)
        })
    }
    else {
        newCell?.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)
        oldCell?.transform = CGAffineTransform(scaleX: 0.8, y: 0.8)
    }
}
```

--------------------------------

### Customize ButtonBar Appearance

Source: https://context7.com/xmartlabs/xlpagertabstrip/llms.txt

Customize the appearance of the ButtonBarPagerTabStripViewController using the `settings` property. This includes colors, fonts, spacing, and the selected indicator bar. You can also define custom animations for cell state changes.

```swift
import XLPagerTabStrip

class StyledButtonBarViewController: ButtonBarPagerTabStripViewController {

    override func viewDidLoad() {
        // Background colors
        settings.style.buttonBarBackgroundColor = UIColor(red: 33/255, green: 33/255, blue: 33/255, alpha: 1)
        settings.style.buttonBarItemBackgroundColor = UIColor(red: 33/255, green: 33/255, blue: 33/255, alpha: 1)

        // Selected indicator bar
        settings.style.selectedBarBackgroundColor = .systemOrange
        settings.style.selectedBarHeight = 3.0
        settings.style.selectedBarVerticalAlignment = .bottom  // .top, .middle, or .bottom

        // Button bar item styling
        settings.style.buttonBarItemFont = UIFont.systemFont(ofSize: 14, weight: .medium)
        settings.style.buttonBarItemTitleColor = UIColor(white: 1, alpha: 0.6)
        settings.style.buttonBarItemLeftRightMargin = 12

        // Layout spacing
        settings.style.buttonBarMinimumInteritemSpacing = 0
        settings.style.buttonBarMinimumLineSpacing = 0
        settings.style.buttonBarLeftContentInset = 16
        settings.style.buttonBarRightContentInset = 16

        // Fill available width (tabs stretch to fill screen)
        settings.style.buttonBarItemsShouldFillAvailableWidth = true

        // Optional: Set button bar height when created programmatically
        settings.style.buttonBarHeight = 48

        // Cell color change callbacks for custom animations
        changeCurrentIndexProgressive = { (oldCell, newCell, progressPercentage, changeCurrentIndex, animated) in
            guard changeCurrentIndex else { return }

            UIView.animate(withDuration: 0.2) {
                oldCell?.label.textColor = UIColor(white: 1, alpha: 0.6)
                oldCell?.transform = CGAffineTransform(scaleX: 0.9, y: 0.9)

                newCell?.label.textColor = .white
                newCell?.transform = .identity
            }
        }

        super.viewDidLoad()
    }

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
        return [
            TabContentViewController(itemInfo: "VIDEOS"),
            TabContentViewController(itemInfo: "PLAYLISTS"),
            TabContentViewController(itemInfo: "COMMUNITY"),
            TabContentViewController(itemInfo: "ABOUT")
        ]
    }
}

```

--------------------------------

### PagerTabStripBehaviour Enum Cases

Source: https://github.com/xmartlabs/xlpagertabstrip/blob/master/README.md

Defines the possible behaviors for the pager indicator updates, including options to skip intermediate view controllers and enable elastic indicator limits.

```swift
public enum PagerTabStripBehaviour {
    case common(skipIntermediteViewControllers: Bool)
    case progressive(skipIntermediteViewControllers: Bool, elasticIndicatorLimit: Bool)
}
```
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