首先创建根tabbarController作为window的根视图，在tabbarController中进行添加子视图控制器，这样就方便管理和层次感更好一些

 func addChildViewController() {
    //主页
    addChileVC(childVC: FindViewController(),title:"发现",image:"tab0",selectedImage:"tab0on")
    //关注
    addChileVC(childVC: FollowViewController(), title: "关注", image: "tab1", selectedImage: "tab1on")
    //我
    addChileVC(childVC: MeViewController(), title: "我的", image: "tab2", selectedImage: "tab2on")
}

这样对于子控制器的管理就会更加简单

/**
添加子试图控制器
:param: childVC NavigationViewController的根视图类型
 :param title tabbar item的文字
 :param image tabbar item的默认图片的名称
 :param selectedImage tabbar item 的选中状态下图片的名称
 */

func addChileVC(childVC:UIViewController,title:String,image:String,selectedImage:String)  {
    childVC.title = title;
    childVC.tabBarItem.image = UIImage.init(named:image)
    childVC.tabBarItem.selectedImage = UIImage.init(named:selectedImage)?.withRenderingMode(UIImageRenderingMode.alwaysOriginal)
    //设置点击之后的颜色
    childVC.tabBarItem.setTitleTextAttributes([NSForegroundColorAttributeName:UIColor.orange], for: UIControlState.selected)
    //设置导航控制器
    let  childNavigation = UINavigationController.init(rootViewController:childVC)
    
    addChildViewController(childNavigation)
    
}

在子视图控制器Find中进行做跳转和传值操作

 //设置背景颜色
    self.view.backgroundColor = UIColor.cyan
     NotificationCenter.default.addObserver(self, selector: #selector(notification(obj:)), name:NSNotification.Name(rawValue: "NotificationName") , object: nil)
    //初始化
    textField = UITextField.init(frame: CGRect(x:0,y:0,width:200,height:30))
    textField.center = CGPoint.init(x:self.view.center.x, y:200)
  //textField.textColor = UIColor.blue
  // textField.backgroundColor = UIColor.green
    textField.placeholder = "请输入内容！！！"
    textField.font = UIFont.systemFont(ofSize: 14)
    textField.layer.borderColor = UIColor.black.cgColor
    textField.layer.borderWidth = 0.5
    view.addSubview(textField)
    
    let sendBtn = UIButton.init(frame:CGRect(x:0,y:0,width:100,height:30))
    sendBtn.backgroundColor = UIColor.orange
    sendBtn.setTitle("点我跳转", for: UIControlState.normal)
    sendBtn.titleLabel?.font = UIFont.systemFont(ofSize: 14)
    sendBtn.setTitleColor(UIColor.black, for: UIControlState.normal)
    sendBtn.center = CGPoint.init(x: self.view.center.x, y: 280);
    sendBtn.addTarget(self, action: #selector(sendBtnClick), for: UIControlEvents.touchUpInside)
    view.addSubview(sendBtn)
    
//方法
func notification(obj: NSNotification)  {
}
func sendBtnClick() {
    let vc = DetailViewController()
    vc.hidesBottomBarWhenPushed = true
    vc.text = self.textField.text!
    self.navigationController?.pushViewController(vc, animated: true)
}