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

does not longer work on iOS14, see updated 2nde answer below

Swift 3.0 version, using an extension:

extension UITabBarController {
    
    private struct AssociatedKeys {
        // Declare a global var to produce a unique address as the assoc object handle
        static var orgFrameView:     UInt8 = 0
        static var movedFrameView:   UInt8 = 1
    }
    
    var orgFrameView:CGRect? {
        get { return objc_getAssociatedObject(self, &AssociatedKeys.orgFrameView) as? CGRect }
        set { objc_setAssociatedObject(self, &AssociatedKeys.orgFrameView, newValue, .OBJC_ASSOCIATION_COPY) }
    }
    
    var movedFrameView:CGRect? {
        get { return objc_getAssociatedObject(self, &AssociatedKeys.movedFrameView) as? CGRect }
        set { objc_setAssociatedObject(self, &AssociatedKeys.movedFrameView, newValue, .OBJC_ASSOCIATION_COPY) }
    }
    
    override open func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        if let movedFrameView = movedFrameView {
            view.frame = movedFrameView
        }
    }
    
    func setTabBarVisible(visible:Bool, animated:Bool) {
        //since iOS11 we have to set the background colour to the bar color it seams the navbar seams to get smaller during animation; this visually hides the top empty space...
        view.backgroundColor =  self.tabBar.barTintColor 
        // bail if the current state matches the desired state
        if (tabBarIsVisible() == visible) { return }
        
        //we should show it
        if visible {
            tabBar.isHidden = false
            UIView.animate(withDuration: animated ? 0.3 : 0.0) {
                //restore form or frames
                self.view.frame = self.orgFrameView!
                //errase the stored locations so that...
                self.orgFrameView = nil
                self.movedFrameView = nil
                //...the layoutIfNeeded() does not move them again!
                self.view.layoutIfNeeded()
            }
        }
            //we should hide it
        else {
            //safe org positions
            orgFrameView   = view.frame
            // get a frame calculation ready
            let offsetY = self.tabBar.frame.size.height
            movedFrameView = CGRect(x: 0, y: 0, width: self.view.frame.width, height: self.view.frame.height + offsetY)
            //animate
            UIView.animate(withDuration: animated ? 0.3 : 0.0, animations: {
                self.view.frame = self.movedFrameView!
                self.view.layoutIfNeeded()
            }) {
                (_) in
                self.tabBar.isHidden = true
            }
        }
    }
    
    func tabBarIsVisible() ->Bool {
        return orgFrameView == nil
    }
}

• This is based on the input from Sherwin Zadeh after a few hours of playing around.
• Instead of moving the tabbar itself it moves the frame of the view, this effectively slides the tabbar nicely out of the bottom of the screen but...
• ... has the advantage that the content displayed inside the UITabbarcontroller is then also taking the full screen!
• note its also using the AssociatedObject functionality to attached data to the UIView without subclassing and thus an extension is possible (extensions do not allow stored properties)