以编程方式在选项卡栏中嵌入视图控制器

Question

我想在点击标签栏项目时动态加载不同的视图控制器。但屏幕显示黑色无法看到视图控制器 :(

感谢任何帮助。这是我正在使用的逻辑：

class TabBarController : UITabBarController,ENSideMenuDelegate{


    override func viewDidLoad() {
        print("Inside Tab bar controller")


        tabBar.items?[0].tag = 0
        tabBar.items?[1].tag = 1
        tabBar.items?[2].tag = 2
        tabBar.items?[3].tag = 3
    }

    override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
        //print("Selected Index :\(self.selectedViewController) \(self.selectedIndex)");
        print("Selected Item is \(item.title)  --> \(item.tag)")

        if(  item.tag == 2 ) {
            print("Navigate to ratings view for service provider ")

            let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main",bundle: nil)
            let destViewController = mainStoryboard.instantiateViewController(withIdentifier: "ViewX")

            //tabBarController?.viewControllers = [destViewController]
            tabBarController?.setViewControllers([destViewController], animated: true) 
        }

    }

}