Making a UITabBarController and UINavigationController Programmatically Swift 4 - ios

Question

I am trying to make a UITabBarController and a UINavigationController programmatically. I've tried many tutorials but most use Swift 3 which is too outdated and doesn't work.
AppDelegate.swift Snippet:
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
window = UIWindow(frame: UIScreen.main.bounds)
let journalVC = JournalTableViewController()
let navController = UINavigationController(rootViewController: journalVC)
window?.rootViewController = navController
window?.makeKeyAndVisible()
return true
}
JournalTableViewController.swift Snippet:
var tabBarCnt = UITabBarController()
override func viewDidLoad() {
super.viewDidLoad()
tabBarCnt = UITabBarController()
tabBarCnt.tabBar.barStyle = .black
let journalVC = JournalTableViewController()
journalVC.tabBarItem = UITabBarItem(tabBarSystemItem: .favorites, tag: 0)
tabBarCnt.viewControllers = [journalVC]
self.view.addSubview(tabBarCnt.view)
}
What works:
The build loads onto the simulator
What doesn't work:
The build crashes once loading onto the simulator
After crashing, the error Thread 1: EXC_BAD_ACCESS (code=2, address=0x7ffee6c2ada8) apears over this line 12 of JournalTableViewController.swift Snippet

Answer 1

If you are going to combine a UITabBarController and a UINavigationController then you will want the tab bar controller to be the root view controller. Each tab can have its own navigation controller if required.
If you make the navigation controller the root, then as soon as you push a new view controller, the tab bar will disappear. By making the tab bar the root, you can have a series of navigation hierarchies and switch quickly between them using the tab buttons.
AppDelegate.swift
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
window = UIWindow(frame: UIScreen.main.bounds)
let journalVC = JournalViewController()
let navController = UINavigationController(rootViewController: journalVC)
let tabBarController = UITabBarController()
navController.tabBarItem = UITabBarItem(tabBarSystemItem: .favorites, tag: 0)
tabBarController.viewControllers = [navController]
window?.rootViewController = tabBarController
window?.makeKeyAndVisible()
return true
}
There is no need for any specific code in your view controller class.
JournalTableViewController.swift Snippet:
override func viewDidLoad() {
super.viewDidLoad()
}

Answer 2

I think there is a typo in your snippet. In the following code, we added an intermediate vc to solve recursive problems.
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
window = UIWindow(frame: UIScreen.main.bounds)
let journalVC = JournalViewController()
let navController = UINavigationController(rootViewController: journalVC)
window?.rootViewController = navController
window?.makeKeyAndVisible()
return true
}
Here is journal vc:
class JournalViewController: UIViewController{
var tabBarCnt = UITabBarController()
override func viewDidLoad() {
super.viewDidLoad()
tabBarCnt = UITabBarController()
tabBarCnt.tabBar.barStyle = .black
let journalVC = JournalTableViewController()
journalVC.tabBarItem = UITabBarItem(tabBarSystemItem: .favorites, tag: 0)
tabBarCnt.viewControllers = [journalVC]
self.view.addSubview(tabBarCnt.view)
}
}
while the tableviewcontroller should be like this:
class JournalTableViewController: UITableViewController{
}