头部搜索导航布局, 修改主题样式

import ‘package:flutter/material.dart‘;import ‘package:flutter_jdshop/services/ScreenAdapter.dart‘;

import ‘Home.dart‘;import ‘Category.dart‘;import ‘Cart.dart‘;import ‘User.dart‘;

class Tabs extends StatefulWidget {  Tabs({Key key}) : super(key: key);

  _TabsState createState() => _TabsState();}

class _TabsState extends State<Tabs> {  int _currentIndex = 0;  PageController _pageController;  @override  void initState() {    super.initState();    this._pageController = new PageController(initialPage: this._currentIndex);  }

  List<Widget> _pageList = [HomePage(), CategoryPage(), CartPage(), UserPage()];

  @override  Widget build(BuildContext context) {

    ScreenAdapter.init(context);

    return Scaffold(      appBar: _currentIndex!=3?AppBar(        leading: IconButton(          icon: Icon(Icons.center_focus_weak, size: 28, color: Colors.black87),          onPressed: null,        ),        title: InkWell(          child: Container(            height: ScreenAdapter.height(68),            decoration: BoxDecoration(              color: Color.fromRGBO(233, 233, 233, 0.8),              borderRadius: BorderRadius.circular(30)            ),            padding: EdgeInsets.only(left: 10),            child: Row(              crossAxisAlignment: CrossAxisAlignment.center,              children: <Widget>[                Icon(Icons.search),                Text("笔记本",style: TextStyle(                  fontSize: ScreenAdapter.size(28)                ))              ],            ),          ),          onTap: (){              Navigator.pushNamed(context, ‘/search‘);

          },        ),        actions: <Widget>[          IconButton(            icon: Icon(Icons.message, size: 28, color: Colors.black87),            onPressed: null,          )        ],      ):AppBar(        title: Text("用户中心"),      ),      body: PageView(        controller: this._pageController,        children: this._pageList,        onPageChanged: (index) {          setState(() {            this._currentIndex = index;          });        },        physics: NeverScrollableScrollPhysics(), //禁止pageView滑动      ),      bottomNavigationBar: BottomNavigationBar(        currentIndex: this._currentIndex,        onTap: (index) {          setState(() {            this._currentIndex = index;            this._pageController.jumpToPage(index);          });        },        type: BottomNavigationBarType.fixed,        fixedColor: Colors.red,        items: [          BottomNavigationBarItem(icon: Icon(Icons.home), title: Text("首页")),          BottomNavigationBarItem(              icon: Icon(Icons.category), title: Text("分类")),          BottomNavigationBarItem(              icon: Icon(Icons.shopping_cart), title: Text("购物车")),          BottomNavigationBarItem(icon: Icon(Icons.people), title: Text("我的"))        ],      ),    );  }}

原文地址：https://www.cnblogs.com/zhaofeis/p/12384936.html