图.png

AppDelegate里的代码

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        //1. 创建window
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.backgroundColor = UIColor.white
        window?.rootViewController = MainViewController()
        //2. 显示window
        window?.makeKeyAndVisible()
        return true
    }

MainViewController.swift

import UIKit

class MainViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        addChildViewControllers()
    }

    /**
     添加所有子控制
     */
    func addChildViewControllers() {
        addChildViewController(childController: HomeTableViewController(), title: "首页", imageName: "tabbar_home")
        addChildViewController(childController: MessageTableViewController(), title: "消息", imageName: "tabbar_message_center")
        addChildViewController(childController: DiscoverTableViewController(), title: "发现", imageName: "tabbar_discover")
        addChildViewController(childController: ProfileTableViewController(), title: "我", imageName: "tabbar_profile")
    }
    
    /**
     初始化子控制器
     
     :param: childController 需要初始化的子控制器
     :param: title           初始化的标题
     :param: imageName       初始化的图片
     */
    func addChildViewController(childController: UIViewController, title:String, imageName:String) {
        // 从内像外设置, nav和tabbar都有
        childController.title = title
        childController.tabBarItem.image = UIImage(named: imageName)
        childController.tabBarItem.selectedImage = UIImage(named: imageName + "_highlighted")
        
        // 注意: Xocde7之前只有文字有效果, 还需要设置图片渲染模式
        tabBar.tintColor = UIColor.orange
        
        // 2.创建导航控制器
        let nav = UINavigationController()
        nav.addChildViewController(childController)
        
        // 3.添加控制器到tabbarVC
        addChildViewController(nav)
    }
}