swift 練習小demo 自定義UITabBarController navBar VC 簡單架構

AppDelegate.swift
import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        let  tabBarController = MianTabBarController()
        
        window?.rootViewController = tabBarController
        return true
    }
MianTabBarController.swift
import UIKit

class MianTabBarController: UITabBarController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.selectedIndex = 0
        setupItem()
        
    }
    
    private func setupItem (){
        let firstVC = ViewController( )
        firstVC.title = "1"
        setupChildVC(vc: firstVC, title: "首頁", image: "tab-bar_icon_empty-main24", selectedImage: "tab bar_icon_main24")
        
        let secondVC = UIViewController()
        secondVC.title = "2"

        secondVC.view.backgroundColor = .green
        setupChildVC(vc: secondVC, title: "消息", image: "tab-bar_icon_empty-message24", selectedImage: "tab-bar_icon_message24")

        let forthVC = UIViewController()
        forthVC.title = "3"

        forthVC.view.backgroundColor = .brown
        setupChildVC(vc: forthVC, title: "我的", image: "tab-bar_icon_mine24", selectedImage: "tab-bar_icon_main24")

        
    }
    private func setupChildVC(vc:UIViewController,title:String,image:String,selectedImage:String){
        
        let nav = UINavigationController(rootViewController: vc)
        
        addChildViewController(nav)
        
        nav .tabBarItem.title = title;
        
        nav.tabBarItem.image = UIImage(named: image)
        
        nav.tabBarItem.selectedImage = UIImage(named: selectedImage)
        
    }
   

    
}