我想要BottomNavigationBar以及没有appBar的Flutter中的TabBar

Question

我想要在不具有appBar的情况下使BottomNavigationBar以及TabBar处于混乱状态，单独地这两个小部件都可以工作，但是当组合在一起时，它说的是在performLayout（）期间引发了以下断言：在布局期间，RenderCustomMultiChildLayoutBox对象被赋予了无限大小。

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Haate Khori',
      theme: ThemeData.light().copyWith(
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage>
    with SingleTickerProviderStateMixin {
  int _selectedIndex = 0;
  static const TextStyle optionStyle =
      TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
  static List<Widget> _widgetOptions = <Widget>[
    Donation(),
    Text(
      'EXPENSES',
      style: optionStyle,
    ),
    Text(
      'ACTIVITIES',
      style: optionStyle,
    ),
    Text(
      'GALLERY',
      style: optionStyle,
    ),
    Text(
      'DONATE US',
      style: optionStyle,
    ),
  ];

  void _onItemTapped(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        body: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            Container(
              child: Padding(
                padding: const EdgeInsets.all(40.0),
                child: SizedBox(
                  height: 70.0,
                ),
              ),
              decoration: BoxDecoration(
                gradient: LinearGradient(
                    begin: Alignment.topLeft,
                    end: Alignment.bottomRight,
                    colors: [Colors.white, Colors.teal], // whitish to gray
                    stops: [0.0, 0.8]),
              ),
            ),
            Container(
              padding: EdgeInsets.all(10.0),
              child: Text(
                'Title goes here',
                style: TextStyle(color: Colors.white, fontSize: 25.0),
              ),
              color: Colors.teal,
            ),
            _widgetOptions.elementAt(_selectedIndex),
          ],
        ),
        bottomNavigationBar: BottomNavigationBar(
          items: const <BottomNavigationBarItem>[
            BottomNavigationBarItem(
              icon: Icon(Icons.home),
              title: Text('Home'),
              backgroundColor: Colors.teal,
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.receipt),
              title: Text('Expenses'),
              backgroundColor: Colors.teal,
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.fiber_smart_record),
              title: Text('Activities'),
              backgroundColor: Colors.teal,
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.collections),
              title: Text('Gallery'),
              backgroundColor: Colors.teal,
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.favorite),
              title: Text('Donate us'),
              backgroundColor: Colors.teal,
            ),
          ],
          currentIndex: _selectedIndex,
          selectedItemColor: Colors.white,
          unselectedItemColor: Colors.white,
          onTap: _onItemTapped,
        ),
      ),
    );
  }
}

class Donation extends StatefulWidget {
  @override
  _DonationState createState() => _DonationState();
}

class _DonationState extends State<Donation>
    with SingleTickerProviderStateMixin {
  TabController tabController;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    tabController = TabController(length: 2, vsync: this);
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        backgroundColor: Colors.white,
        body: Column(
          children: <Widget>[
            SizedBox(
              height: 10.0,
            ),
            TabBar(
              labelColor: Colors.teal,
              controller: tabController,
              tabs: <Widget>[
                Tab(
                  child: Text('Tab1'),
                ),
                Tab(
                  child: Text('Tab2'),
                )
              ],
            ),
            Expanded(
              child: Container(
                child: TabBarView(
                  controller: tabController,
                  children: <Widget>[
                    Text(
                      'Hello',
                      style: TextStyle(fontSize: 20.0),
                      textAlign: TextAlign.center,
                    ),
                    Text(
                      'World',
                      style: TextStyle(
                        fontSize: 20.0,
                      ),
                      textAlign: TextAlign.center,
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

Target : What I want和This is what I am getting

Answer 1

import 'package:flutter/material.dart';
import 'package:transportWeb/provider/dimensions.dart';
import 'package:transportWeb/screens/mainScreenViews/aboutUs.dart';
import 'package:transportWeb/screens/mainScreenViews/contactUs.dart';
import 'package:transportWeb/screens/mainScreenViews/home.dart';
import 'package:url_launcher/url_launcher.dart';
import '../constants.dart';

class MainScreen extends StatefulWidget {
  @override
  _MainScreenState createState() => _MainScreenState();
}

class _MainScreenState extends State<MainScreen>
    with SingleTickerProviderStateMixin {
  TabController _tabController;
  var _currentDateTime = DateTime.now();
  var _currentHours;

  @override
  void initState() {
    super.initState();
    _currentHours = _currentDateTime.hour;
    print(_currentHours);
    _tabController = TabController(length: 3, vsync: this, initialIndex: 1);
  }

  @override
  void dispose() {
    // TODO: implement dispose
    super.dispose();
    _tabController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    Dimensions(context);
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        tooltip: "Request Call",
        backgroundColor: Colors.deepPurpleAccent,
        onPressed: () {
          showDialog(
            context: context,
            builder: (BuildContext context) {
              return AlertDialog(
                title: Text(
                  "Enter your Phone no",
                  style: kh3,
                ),
              );
            },
          );
        },
        child: Icon(
          Icons.phone,
          color: Colors.white,
          size: 30,
        ),
      ),
      body: ListView(
        children: [
          Container(
            padding: EdgeInsets.symmetric(horizontal: 20, vertical: 0),
            height: 70,
            decoration: BoxDecoration(
              color: Colors.transparent,
              border: Border(
                bottom: BorderSide(
                  color: Colors.grey.shade200,
                  width: 3,
                ),
              ),
            ),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.end,
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                Padding(
                  padding: const EdgeInsets.only(bottom: 15),
                  child: RichText(
                    text: TextSpan(
                      style: kh2.copyWith(letterSpacing: 10),
                      children: <TextSpan>[
                        TextSpan(text: "JSSR "),
                        TextSpan(text: "Road"),
                        TextSpan(
                          text: "L",
                          style: kh2.copyWith(color: Colors.red),
                        ),
                        TextSpan(text: "ines"),
                      ],
                    ),
                  ),
                ),
                Expanded(
                  child: SizedBox(
                    width: 0,
                    height: 0,
                  ),
                ),
                TabBar(
                  isScrollable: true,
                  indicatorColor: Colors.black,
                  indicatorSize: TabBarIndicatorSize.label,
                  labelColor: Colors.black,
                  unselectedLabelColor: Colors.grey.withOpacity(0.6),
                  controller: _tabController,
                  tabs: [
                    Tab(
                      child: Padding(
                        padding: const EdgeInsets.only(bottom: 10),
                        child: Text(
                          "HOME",
                          style: kh5,
                        ),
                      ),
                    ),
                    Tab(
                      child: Padding(
                        padding: const EdgeInsets.only(bottom: 10),
                        child: Text(
                          "ABOUT US",
                          style: kh5,
                        ),
                      ),
                    ),
                    Tab(
                      child: Padding(
                        padding: const EdgeInsets.only(bottom: 10),
                        child: Text(
                          "CONTACT US",
                          style: kh5,
                        ),
                      ),
                    ),
                  ],
                ),
                GestureDetector(
                  onTap: () {
                    launch(
                        "https://pub.dev/packages/url_launcher#-installing-tab-");
                  },
                  child: Container(
                    margin: EdgeInsets.only(left: 15, bottom: 12),
                    padding: EdgeInsets.symmetric(vertical: 10, horizontal: 10),
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(5),
                      color: Colors.deepPurpleAccent,
                    ),
                    child: Text(
                      "DOWNLOAD APP",
                      style: kh5.copyWith(color: Colors.white),
                    ),
                  ),
                ),
              ],
            ),
          ),
          Container(
            width: double.maxFinite,
            height: double.maxFinite,
            child: TabBarView(
              controller: _tabController,
              children: [
                Home(),
                AboutUs(),
                ContactUs(),
              ],
            ),
          )
        ],
      ),
    );
  }
}