flutter的tabbar_flutter tab 获取text

import 'package:color_dart/color_dart.dart';
import 'package:flutter/material.dart';
 
class Order extends StatefulWidget {
  static _OrderState _orderState;
 
  getAppBar() {
    return _orderState.createAppBar();
  }
 
  Order() {
    _orderState = _OrderState();
  }
 
  @override
  _OrderState createState() => _OrderState();
}
 
class _OrderState extends State<Order> with TickerProviderStateMixin {
  static List<Tab> tabs = [
    Tab(text: '全部'),
    Tab(text: '未完成'),
    Tab(
      text: '已完成',
    )
  ];
  static TabController _tabController;
 
  AppBar createAppBar() {
    _tabController = TabController(vsync: this, length: tabs.length);
    return AppBar(
        backgroundColor: Colors.white,
        brightness: Brightness.dark,
        elevation: 0,
        centerTitle: true,
        title: Text(
          "订单列表",
          style: TextStyle(
              color: rgba(56, 56, 56, 1),
              fontSize: 18,
              fontWeight: FontWeight.bold),
        ),
        bottom: PreferredSize(  //常用在appbar的bottom 可以对子控制没有约束
            preferredSize: Size.fromHeight(44),
            child: Container(
              child: Column(
                children: [
                  SizedBox(
                    height: 1,
                    width: double.infinity,
                    child: Padding(
                        padding: EdgeInsets.symmetric(horizontal: 20),
                        child: Divider(
                          color: Colors.yellow,
                          height: 2,
                        )),
                  ),
                  TabBar(
                    tabs: tabs,
                    labelColor: rgba(136, 175, 213, 1),
                    labelStyle: TextStyle(fontWeight: FontWeight.bold),
                    unselectedLabelStyle: TextStyle(fontSize: 15),
                    unselectedLabelColor: rgba(80, 80, 80, 1),
                    controller: _tabController,
                  ),
                ],
              ),
            )));
  }
 
  @override
  Widget build(BuildContext context) {
    return Container(
      color: rgba(248, 248, 248, 1),
      child: TabBarView(
        children: [Text("xxxx"),
          Text("xxxx"),
          Text("xxxx")
        ],
        controller: _tabController,
      ),
    );
  }
}