如何在AppDelegate.swift中使用Tab Bar Controller

Question

如何在我的AppDelegate.swift中使用Tab Bar Controller

import UIKit

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

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        let rootViewController = self.window!.rootViewController

        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)

    // Centre View Controller
            let centerViewController = mainStoryboard.instantiateViewControllerWithIdentifier("ViewController") as! ViewController

    // left view Controller along with centre view controller 
            let leftViewController = mainStoryboard.instantiateViewControllerWithIdentifier("LeftSideViewController") as! LeftSideViewController

    // Right view Controller along with centre view controller         
            let rightViewController = mainStoryboard.instantiateViewControllerWithIdentifier("RightSideViewController") as! RightSideViewController


        let leftSideNav = UINavigationController(rootViewController: leftViewController)
        let centerNav = UINavigationController(rootViewController: centerViewController)
        let rightNav = UINavigationController(rootViewController: rightViewController)

        centerContainer = MMDrawerController(centerViewController: centerNav, leftDrawerViewController: leftSideNav,rightDrawerViewController:rightNav)

        centerContainer!.openDrawerGestureModeMask = MMOpenDrawerGestureMode.PanningCenterView;
        centerContainer!.closeDrawerGestureModeMask = MMCloseDrawerGestureMode.PanningCenterView;

        window!.rootViewController = centerContainer
        window!.makeKeyAndVisible()

        return true
    }
}