Swift: how to show a tab bar controller after a login view

Question

I have seen many posts similar to this here but they are all about Objective-C while I am developing my app in Swift. As you can see from the image I have a login screen view an

Answer 1

func setTabBarVisible(visible:Bool, animated:Bool) {

//* This cannot be called before viewDidLayoutSubviews(), because the frame is not set before this time

    // bail if the current state matches the desired state
    if (tabBarIsVisible() == visible) { return }

    // get a frame calculation ready
    let frame = self.tabBarController?.tabBar.frame
    let height = frame?.size.height
    let offsetY = (visible ? -height! : height)

    // zero duration means no animation
    let duration:NSTimeInterval = (animated ? 0.3 : 0.0)

    //  animate the tabBar
    if frame != nil {
        UIView.animateWithDuration(duration) {
            self.tabBarController?.tabBar.frame = CGRectOffset(frame!, 0, offsetY!)
            return
        }
    }
}

func tabBarIsVisible() ->Bool {
    return self.tabBarController?.tabBar.frame.origin.y < CGRectGetMaxY(self.view.frame)
}

// Call the function from tap gesture recognizer added to your view (or button)

@IBAction func tapped(sender: AnyObject) {
    setTabBarVisible(!tabBarIsVisible(), animated: true)
}