network_tabs.dart

import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

void main() => runApp(MyApp());

Future<Post> fetchPost() async {
  final response = await http.get('https://jsonplaceholder.typicode.com/posts/1');
  if (response.statusCode == 200) {
    return Post.fromJson(json.decode(response.body));
  } else {
    throw Exception('Failed to load post');
  }
}

class Post {
  final int userId;
  final int id;
  final String title;
  final String body;

  Post({this.userId, this.id, this.title, this.body});

  factory Post.fromJson(Map<String, dynamic> json) {
    return Post(
      userId: json['userId'],
      id: json['id'],
      title: json['title'],
      body: json['body'],
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  TabController _controller;
  List<Post> menuCategoryList = [];

  @override
  void initState() {
    super.initState();
    _controller = TabController(vsync: this, length: menuCategoryList.length);
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        bottom: TabBar(
          controller: _controller,
          tabs: menuCategoryList.map((Post post) {
            return Tab(child: Text(post.title));
          }).toList(),
        ),
      ),
      body: TabBarView(
        controller: _controller,
        children: menuCategoryList.map((Post post) {
          final String label = post.title.toLowerCase();
          return Center(
            child: Text(
              'This is the $label tab',
              style: const TextStyle(fontSize: 36),
            ),
          );
        }).toList(),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          fetchPost()
            .then((Post post) {
              setState(() {
                menuCategoryList = new List<Post>.from(menuCategoryList)
                  ..add(post);
                _controller = TabController(vsync: this, length: menuCategoryList.length);
                });
            });
        },
        child: Icon(Icons.add),
      ),
    );
  }
}