A custom UINavigationController that enables the scrolling of the navigation bar alongside the scrolling of an observed content view

Versioning notes

Version 2.x is written as a subclass of UINavigationController, in Swift.
Version 2.0.0 introduced Swift 2.0 syntax.
Version 3.0.0 introduced Swift 3.0 syntax.
Version 4.0.0 introduced Swift 4.0 syntax.
Version 5.1.0 introduced Swift 4.2 syntax.

If you are looking for the category implementation in Objective-C, make sure to checkout version 1.x and prior, although the 2.x is recomended.

Screenshot

Setup with CocoaPods

pod 'AMScrollingNavbar'

use_frameworks!

Setup with Carthage

github "andreamazz/AMScrollingNavbar"

Usage

Make sure to use ScrollingNavigationController instead of the standard UINavigationController. Either set the class of your UINavigationController in your storyboard, or create programmatically a ScrollingNavigationController instance in your code.

Use followScrollView(_: delay:) to start following the scrolling of a scrollable view (e.g.: a UIScrollView or UITableView).

Swift

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

    if let navigationController = navigationController as? ScrollingNavigationController {
        navigationController.followScrollView(tableView, delay: 50.0)
    }
}

Objective-C

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [(ScrollingNavigationController *)self.navigationController followScrollView:self.tableView delay:0 scrollSpeedFactor:1 collapseDirection:NavigationBarCollapseDirectionScrollDown followers:nil];
}

Use stopFollowingScrollview() to stop the behaviour. Remember to call this function on disappear:

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

    if let navigationController = navigationController as? ScrollingNavigationController {
        navigationController.stopFollowingScrollView()
    }
}

ScrollingNavigationViewController

To DRY things up you can let your view controller subclass ScrollingNavigationViewController, which provides the base setup implementation. You will just need to call followScrollView(_: delay:):

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

    if let navigationController = navigationController as? ScrollingNavigationController {
        navigationController.followScrollView(tableView, delay: 50.0)
    }
}

Followers

To move another view, like a toolbar, alongside the navigation bar you can provide the view or multiple views as the followers parameter. Since you might want to have the follower up or down, you’ll have to specify the scroll direction of the view once it starts to follow the navigation bar:

if let navigationController = navigationController as? ScrollingNavigationController {
    navigationController.followScrollView(tableView, delay: 50.0, followers: [NavigationBarFollower(view: customFooter, direction: .scrollDown)])
}

Note that when navigating away from the controller the followers might keep the scroll offset. Refer to Handling navigation for proper setup.

Additional scroll

If you want to furhter scroll the navigation bar out of the way, you can use the optional parameter additionalOffset in the followScrollView call.

Scrolling the TabBar

You can also pass a UITabBar in the followers array:

if let navigationController = navigationController as? ScrollingNavigationController {
    navigationController.followScrollView(tableView, delay: 50.0, followers: [tabBarController.tabBar])
}

ScrollingNavigationControllerDelegate

You can set a delegate to receive a call when the state of the navigation bar changes:

if let navigationController = navigationController as? ScrollingNavigationController {
    navigationController.scrollingNavbarDelegate = self
}

Delegate function:

func scrollingNavigationController(_ controller: ScrollingNavigationController, didChangeState state: NavigationBarState) {
    switch state {
    case .collapsed:
        print("navbar collapsed")
    case .expanded:
        print("navbar expanded")
    case .scrolling:
        print("navbar is moving")
    }
}

Handling navigation

If the view controller with the scroll view pushes new controllers, you should call showNavbar(animated:) in your viewWillDisappear(animated:):

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    if let navigationController = navigationController as? ScrollingNavigationController {
      navigationController.showNavbar(animated: true)
    }
}

Scrolling to top

When the user taps the status bar, by default a scrollable view scrolls to the top of its content. If you want to also show the navigation bar, make sure to include this in your controller:

func scrollViewShouldScrollToTop(_ scrollView: UIScrollView) -> Bool {
    if let navigationController = navigationController as? ScrollingNavigationController {
        navigationController.showNavbar(animated: true, scrollToTop: true)
    }
    return true
}

Scroll speed

You can control the speed of the scrolling using the scrollSpeedFactor optional parameter:

controller.followScrollView(view, delay: 0, scrollSpeedFactor: 2)

Check out the sample project for more details.

Changing UINavigationBar.tintColor

AMScrollingNavBar maintains its own copy of the UINavigationBar’s tintColor property. You need to notify the AMScrollingNavBar of a tint change by calling navBarTintUpdated():

navigationBar.tintColor = UIColor.red
controller.navBarTintUpdated()