customtab.dart

import 'package:flutter/material.dart';

class CustomBottom extends StatefulWidget {
  @override
  AppState createState() => AppState();
}

class AppState extends State<CustomBottom> with SingleTickerProviderStateMixin {
  TabController _controller;

  @override
  void initState() {
    super.initState();
    _controller = new TabController(length: 2, vsync: this);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Budget'),),
      body: TabBarView(
        controller: _controller,
        children: <Widget>[new NewPage('First'), new NewPage('Second')],
      ),
      bottomNavigationBar: new Material(
        child: TabBar(
          labelColor: Colors.red,
          indicatorColor: Colors.red,
          unselectedLabelColor: Colors.grey,
          controller: _controller,
          tabs: <Widget>[
            new MyTab(
              Icon(
                Icons.info,
              ),
              'Details',
            ),
            new MyTab(Icon(Icons.access_time), 'Timeline', false)
          ],
        ),
      ),
    );
  }
}

class MyTab extends StatelessWidget implements Tab {
  final Icon _icon;
  final String _text;
  final bool _dividerRequired;

  MyTab(this._icon, this._text, [this._dividerRequired = true]);

  @override
  Widget build(BuildContext context) {
    return _dividerRequired
        ? Row(
            children: <Widget>[
              new Expanded(
                child: Tab(
                  icon: _icon,
                  text: _text,
                ),
                flex: 1,
              ),
              new Container(
                width: 1.0,
                height: 30.0,
                color: Colors.grey,
              )
            ],
          )
        : Tab(
            icon: _icon,
            text: _text,
          );
  }

  // TODO: implement child
  @override
  Widget get child => null;

  // TODO: implement icon
  @override
  Widget get icon => _icon;

  // TODO: implement text
  @override
  String get text => _text;
}

class NewPage extends StatelessWidget {
  final String title;

  NewPage(this.title);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text(title),
      ),
    );
  }
}