NavigationBar、TabBar Problem

//
//  ViewController.swift
//  Practice2：Navigation、TabBar
//
//  Created by Jhen Mu on 2021/7/19.
//

import UIKit

class ViewController: UIViewController {
    //MARK:- Properties




    //MARK:- Methods
    @objc func check(){
        print("check button action")
    }

    @objc func article(){
        self.navigationController?.pushViewController(
              ArticleViewController(), animated: true)
    }

    @objc func setting(){
        self.navigationController?.pushViewController(
              SettingViewController(), animated: true)
    }


    //MARK:- Life Cycle
    override func loadView() {
        super.loadView()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        theNavigation()
        theTabBar()

    }
    //MARK:-setNavigationBar
    func theNavigation(){
        self.view.backgroundColor = UIColor.white
        self.title = "HomePage"
        self.navigationController?.navigationBar.barTintColor = UIColor.white //設置導覽列的顏色
        self.navigationController?.navigationBar.isTranslucent = false //

        let rightButton = UIBarButtonItem(title: "Setting",
                                          style: .plain,
                                          target: self,
                                          action: #selector(ViewController.setting))
        let leftButton = UIBarButtonItem(title: "Article",
                                         style: .plain,
                                         target: self,
                                         action: #selector(ViewController.article))
        self.navigationItem.rightBarButtonItem = rightButton
        self.navigationItem.leftBarButtonItem = leftButton

    }

    //MARK:-setTabBar
    func theTabBar(){
        self.tabBarController?.tabBar.barTintColor = UIColor.white
        self.tabBarController?.tabBar.isTranslucent = false
        let theTabBar = UITabBarController()
        theTabBar.tabBar.backgroundColor = UIColor.white

        let mainpage = ViewController()
        let article = ArticleViewController()
        let settings = SettingViewController()
        let intro = IntroViewController()

        article.tabBarItem = UITabBarItem(title: "Article",
                                          image:UIImage(named:"paid-articles"),
                                          tag: 200)
        settings.tabBarItem = UITabBarItem(title: "Setting",
                                           image:UIImage(named:"settings"),
                                           tag: 200)
        intro.tabBarItem = UITabBarItem(title: "Introdce",
                                        image:UIImage(named:"light-bulb"),
                                        tag: 200)
        theTabBar.viewControllers = [
            mainpage,article,settings,intro
        ]
        theTabBar.selectedIndex = 2

    }

    //在viewDidLoad之後被執行，時間點在view被呈現之前，每次切換頁面時都會被執行
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        print("viewWillAppear")
    }


    //時間點在viewWillAppear呈現之後被執行，時間在View呈現後，每次切換到這個頁面都會被執行
    override func viewDidAppear(_ animated: Bool) {
        print("viewDidAppear")
    }

    //執行的時間點在 View 要結束前，每次要切換到別頁或是退出這個頁面時都會執行。
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        print("viewWillDisappear")
    }

    //執行的時間點在 View 完全結束後，每次要切換到別頁或是退出這個頁面時都會執行。
    override func viewDidDisappear(_ animated: Bool) {
        print("viewDidDisappear")
    }





}