LeftSideMenu without Storyboard swift 2 - ios

Question

I need your help.
I'm developing a app without Storyboard (using xib), in my project I have two views controllers.
In the main view (after a login) I need to put a button on top of the view to open a left side menu.
This is how I call the MainView on LoginViewController
#IBAction func logar(){
let vc = MainViewController(nibName: "MainViewController", bundle: nil)
self.navigationController!.pushViewController(vc, animated: true)
}
I imported SWRevealViewController, and this is my MainViewController:
import UIKit
class MainViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
//hide BackButton
self.navigationItem.hidesBackButton = true
//image
var image = UIImage(named: "menuBtn")
image = image?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
//lefBarButonItem
let newBackButton = UIBarButtonItem(image: image, style: .Plain, target: self, action: #selector(MainViewController.openMenu))
self.navigationItem.leftBarButtonItem = newBackButton;
}
func openMenu(){
let frontViewController = LeftMenuTableViewController()
let rearViewController = MainViewController()
//create instance of swRevealVC based on front and rear VC
let swRevealVC = SWRevealViewController(rearViewController: rearViewController, frontViewController: frontViewController);
swRevealVC.toggleAnimationType = SWRevealToggleAnimationType.EaseOut;
swRevealVC.toggleAnimationDuration = 0.30;
//set swRevealVC as rootVC of windows
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
appDelegate.window!.rootViewController = swRevealVC
}
}
When I press the button the LeftMenu occupy all the view, not like a partial view.
Any help would be appreciated. Thank you!