How to hide tab bar with animation in iOS?

Question

So I have a button that is connected to a IBAction. When I press the button I want to hide the tab bar in my iOS app with a animation. This [self setTabBarHidden:hidde

Answer 1

I went through the previous posts, so I came out with the solution below as subclass of UITabBarController

Main points are:

• Written in Swift 5.1
• Xcode 11.3.1
• Tested on iOS 13.3
• Simulated on iPhone 11 and iPhone 8 (so with and without notch)
• Handles the cases where the user taps on the different tabs
• Handles the cases where we programmatically change the value of selectedIndex
• Handles the view controller orientation changes
• Handles the corner casere where the app moved to background and back to foreground

Below the subclass TabBarController:

class TabBarController: UITabBarController {

    //MARK: Properties
    
    private(set) var isTabVisible:Bool = true
    private var visibleTabBarFrame:CGRect = .zero
    private var hiddenTabBarFrame:CGRect = .zero
    
    override var selectedIndex: Int {
        didSet { self.updateTabBarFrames() }
    }
    
    //MARK: View lifecycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.delegate = self
        NotificationCenter.default.addObserver(self, selector: #selector(appWillEnterForeground(_:)), name: UIApplication.willEnterForegroundNotification, object: nil)
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        self.calculateTabBarFrames()
    }
    
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)
        coordinator.animate(alongsideTransition: { (_) in }) { (_) in
            // when orientation changes, the tab bar frame changes, so we need to update it to the expected state
            self.calculateTabBarFrames()
            self.updateTabBarFrames()
        }
    }
    
    @objc private func appWillEnterForeground(_ notification:Notification){
        self.updateTabBarFrames()
    }
    
    //MARK: Private
    
    /// Calculates the frames of the tab bar and the expected bounds of the shown view controllers
    private func calculateTabBarFrames() {
        self.visibleTabBarFrame = self.tabBar.frame
        self.hiddenTabBarFrame = CGRect(x: self.visibleTabBarFrame.origin.x, y: self.visibleTabBarFrame.origin.y + self.visibleTabBarFrame.height, width: self.visibleTabBarFrame.width, height: self.visibleTabBarFrame.height)
    }
    
    /// Updates the tab bar and shown view controller frames based on the current expected tab bar visibility
    /// - Parameter tabIndex: if provided, it will update the view frame of the view controller for this tab bar index
    private func updateTabBarFrames(tabIndex:Int? = nil) {
        self.tabBar.frame = self.isTabVisible ? self.visibleTabBarFrame : self.hiddenTabBarFrame
        if let vc = self.viewControllers?[tabIndex ?? self.selectedIndex] {
            vc.additionalSafeAreaInsets.bottom = self.isTabVisible ? 0.0 : -(self.visibleTabBarFrame.height - self.view.safeAreaInsets.bottom)

        }
        self.view.layoutIfNeeded()
    }
    
    //MARK: Public
    
    /// Show/Hide the tab bar
    /// - Parameters:
    ///   - show: whether to show or hide the tab bar
    ///   - animated: whether the show/hide should be animated or not
    func showTabBar(_ show:Bool, animated:Bool = true) {
        guard show != self.isTabVisible else { return }
        self.isTabVisible = show
        guard animated else {
            self.tabBar.alpha = show ? 1.0 : 0.0
            self.updateTabBarFrames()
            return
        }
        UIView.animate(withDuration: 0.25, delay: 0.0, options: [.beginFromCurrentState,.curveEaseInOut], animations: {
            self.tabBar.alpha = show ? 1.0 : 0.0
            self.updateTabBarFrames()
        }) { (_) in }
    }
  
}

extension TabBarController: UITabBarControllerDelegate {
    override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
        if let tabIndex = self.tabBar.items?.firstIndex(of: item) {
            self.updateTabBarFrames(tabIndex: tabIndex)
        }
    }
}

Sample usage from within a shown view controller:

// hide the tab bar animated (default)
(self.tabBarController as? TabBarController)?.showTabBar(false)
// hide the tab bar without animation
(self.tabBarController as? TabBarController)?.showTabBar(false, animated:false)

Sample output iPhone 11

Sample output iPhone 8

EDIT :

• Updated the code to respect the safe area bottom inset
• If you're experiencing issues with this solution and your tab bar contains a navigation controller as direct child in the viewControllers array, you may want to make sure that the navigation controller topViewController has the property extendedLayoutIncludesOpaqueBars set to true (you can set this directly from the Storyboard). This should resolve the problem

Hope it helps someone :)