自定义appbarTitle + pageview 实现类似安卓tabHost+Fragment

import 'package:flutter/material.dart';

class Index extends StatefulWidget {
    
    
  const Index({
    
    Key? key}) : super(key: key);

  @override
  State<Index> createState() => _IndexState();
}

var currentTab = 0;

List<Widget> list = [];
PageController? myController;

class _IndexState extends State<Index> {
    
    
  leftTab() {
    
    
    return InkWell(
      onTap: () {
    
    
        setState(() {
    
    
          currentTab = 0;
          myController?.animateTo(0, duration: const Duration(microseconds: 200), curve: Curves.linear);
        });
      },
      child: Container(
          margin: const EdgeInsets.all(5),
          decoration: BoxDecoration(
              color: currentTab == 0 ? Colors.yellow : Colors.red,
              borderRadius: currentTab == 0
                  ? BorderRadius.circular(10)
                  : BorderRadius.zero),
          child: Text("首页",
              style: TextStyle(
                  color: currentTab == 0 ? Colors.green : Colors.black))),
    );
  }

  rightTab() {
    
    
    return InkWell(
      onTap: () {
    
    
        setState(() {
    
    
          currentTab = 1;
          myController?.animateTo(MediaQuery.of(context).size.width, duration: const Duration(microseconds: 200), curve: Curves.linear);
        });
      },
      child: Container(
          decoration: BoxDecoration(
              color: currentTab == 1 ? Colors.yellow : Colors.red,
              borderRadius: currentTab == 1
                  ? BorderRadius.circular(10)
                  : BorderRadius.zero),
          child: Text("我的",
              style: TextStyle(
                  color: currentTab == 1 ? Colors.green : Colors.black))),
    );
  }

  Widget buildTitleView() {
    
    
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [leftTab(), rightTab()],
    );
  }

  @override
  Widget build(BuildContext context) {
    
    
    return Scaffold(
      appBar: AppBar(
        title: buildTitleView(),
        titleTextStyle: const TextStyle(fontSize: 36, color: Colors.green),
        toolbarHeight: 100.0,
        centerTitle: true,
        leading: const Icon(Icons.add),
      ),
      body: PageView(
        children: list,
        onPageChanged: (index) {
    
    
          setState(() {
    
    
            currentTab = index;
          });
        },
        controller: myController,
      ),
      // body: Column(
      //   crossAxisAlignment: CrossAxisAlignment.center,
      //   mainAxisAlignment: MainAxisAlignment.center,
      //   children: [
      //     Container(
      //       color: Colors.lightBlueAccent,
      //       alignment: Alignment.center,
      //       child: Text("day03学习"),
      //     )
      //   ],
      // ),
    );
  }

  @override
  void initState() {
    
    
    super.initState();
    list = [const Text("首页内容"), const Text("我的内容")];
    myController = PageController(initialPage: 0, keepPage: true);
  }
}

```c