SwiftでTabBarの仕組みを EmptyApplicationから作ってみた。

xibファイルと連携する方法。
Storyboardでの画面遷移管理がまだ苦手なので・・・。
ちなみに言語の仕様や文法を完全には理解していないので、記述方法等が間違っていたらご指摘願います。

AppDelegate.swift

import UIKit
import CoreData

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
                            
    var window: UIWindow?


    func application(application: UIApplication, 
                    didFinishLaunchingWithOptions 
                    launchOptions: NSDictionary?) -> Bool {
        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        // Override point for customization after application launch.
        self.window!.backgroundColor = UIColor.whiteColor()
        
        //Create main ViewControllers
        var firstViewController:FirstViewController = 
                FirstViewController(nibName: "FirstViewController", bundle: nil)
        var secondViewController:SecondViewController = 
                SecondViewController(nibName: "SecondViewController", bundle: nil)
        var thirdViewController:ThirdViewController = 
                ThirdViewController(nibName: "ThirdViewController", bundle: nil)
        
        //Create NavigationControllers
        var firstNavigationController:UINavigationController = 
                UINavigationController(rootViewController:firstViewController)
        var secondNavigationController:UINavigationController = 
                UINavigationController(rootViewController:secondViewController)
        var thirdNavigationController:UINavigationController = 
                UINavigationController(rootViewController:thirdViewController)
        var naviControllerList:Array<UINavigationController> = 
                [
                    firstNavigationController, 
                    secondNavigationController, 
                    thirdNavigationController
                ]
        
        //Create TabBarController
        var tabBarController:UITabBarController = UITabBarController()
        tabBarController.setViewControllers(naviControllerList, animated: true)
        
        self.window!.rootViewController = tabBarController
        self.window!.makeKeyAndVisible()
        return true
    }

各UIViewController init の部分が不安であるが…。

FirstViewController.swift

import Foundation
import UIKit

class FirstViewController : UIViewController
{
    init(nibName:String!, bundle: NSBundle!)
    {
        super.init(nibName: nibName, bundle: bundle)
        
        //Create Navigationbar
        self.navigationItem.title = "First VIEW CONTROLLER"
        
        //Create TabBar
        self.title = "First"

    }
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
    }

}

SecondViewController.swift

import Foundation
import UIKit

class SecondViewController : UIViewController
{
    init(nibName:String!, bundle: NSBundle!)
    {
        super.init(nibName: nibName, bundle: bundle)
            
        //Create Navigationbar
        self.navigationItem.title = "Second VIEW CONTROLLER"
        
        //Create TabBar
        self.title = "Second"

    }
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
    }
    
}

ThirdViewController.swift

import Foundation
import UIKit

class ThirdViewController :UIViewController
{
    init(nibName:String!, bundle: NSBundle!)
    {
        super.init(nibName: nibName, bundle: bundle)
        
        //Create Navigationbar
        self.navigationItem.title = "Third VIEW CONTROLLER"
        
        //Create TabBar
        self.title = "Third"

    }
    override func viewDidLoad()
    {
        super.viewDidLoad()
    }
    
}

この他、AppDelegate.swiftファイルでnibName設定しているxibファイルが必要となります。