弹窗与轮动图

Dialog弹窗，用于显示信息、提示用户或获取用户输入，PageView则是一个可滑动的页面视图，用于展示多页面切换效果。

1 Dialog弹出窗口

• AlertDialog(弹窗提示信息)、SimpleDialog(弹窗选择信息)、showModalBottomSheet(底部弹出窗口)。
• 下载包：到pubspec.yaml的dependencies中加入fluttertoast: ^8.2.4，保存后点Pub get下载。
• 如果报错，参看：uses-sdk:minSdkVersion 16 cannot be smaller than version 19 declared in library。

1-1 内置的Dialog

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - dialog.dart
  - routes/
    - routes.dart
- main.dart

(1) user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

(2) tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("内置的Dialog")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

(3) main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

(4) home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/dialog");
            },
            child: const Text("Dialog演示"),
          ),
        ],
      ),
    );
  }
}

(5) dialog.dart

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

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

  @override
  State<DialogPage> createState() => _DialogPageState();
}

class _DialogPageState extends State<DialogPage> {
  void _alertDialog() async {
    // print("_alertDialog");
    var result = await showDialog(context: context, builder: (context) {
      return AlertDialog(
        title: const Text("提示信息！"),
        content: const Text("您确定要删除吗？"),
        actions: [
          TextButton(onPressed: () {
            print("OK");
            // 点击按钮关闭窗口
            Navigator.of(context).pop("OK");
          }, child: const Text("确定")),
          TextButton(onPressed: () {
            print("Cancel");
            // 外层result打印信息
            Navigator.of(context).pop("Cancel");
          }, child: const Text("取消")),
        ],
      );
    }); print(result);
  }

  void _simpleDialog() async {
    // barrierDismissible
    // print("_simpleDialog");
    // 点灰色背景，弹窗不消失
    var result = await showDialog(
      barrierDismissible: false, context: context, builder: (context) {
        return SimpleDialog(
          title: const Text("请选择语言："),
          children: [
            SimpleDialogOption(
              // Navigator.of().pop()方法一
              onPressed: () {
                print("汉语");
                Navigator.of(context).pop("汉语");
              }, child: const Text("汉语"),
            ), const Divider(),
            SimpleDialogOption(
              // Navigator.pop()方法二
              onPressed: () {
                print("英语");
                Navigator.pop(context, "英语");
              }, child: const Text("英语"),
            ), const Divider(),
            SimpleDialogOption(
              // pop不传第二个参数值返回null
              onPressed: () {
                print("日语");
                Navigator.pop(context, "日语");
              }, child: const Text("日语"),
            ), const Divider(),
          ],
        );
      },
    ); print("----"); print(result);
  }

  void _modelBottomSheet() async {
    // print("_modelBottomSheet");
    var result = await showModalBottomSheet(context: context, builder: (context) {
      return SizedBox(
        height: 200,
        child: Column(
          children: [
            ListTile(
              title: const Text("分享"),
              onTap: () {print("分享"); Navigator.pop(context, "分享");},
            ), const Divider(),
            ListTile(
              title: const Text("收藏"),
              onTap: () {print("收藏"); Navigator.pop(context, "收藏");},
            ), const Divider(),
            ListTile(
              title: const Text("取消"),
              onTap: () {print("取消"); Navigator.pop(context, "取消");},
            ),
          ],
        ),
      );
    }); print("****"); print(result);
  }

  void _toast() {
    // print("_toast");
    // 使用该功能，需要重新flutter run
    Fluttertoast.showToast(
      msg: "提示信息",
      // 值针对Android平台，1秒消失
      toastLength: Toast.LENGTH_SHORT,
      // 5秒消失
      // toastLength: Toast.LENGTH_LONG,
      // 调整方位
      gravity: ToastGravity.TOP,
      // 提示时间，针对iOS和Web
      timeInSecForIosWeb: 1,
      // 背景颜色
      backgroundColor: Colors.black,
      // 文本颜色
      textColor: Colors.white,
      // 文本字体大小
      fontSize: 16.0,
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Dialog")),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              onPressed: _alertDialog,
              child: const Text("弹窗提示信息：AlertDialog"),
            ), const SizedBox(height: 20),
            ElevatedButton(
              onPressed: _simpleDialog,
              child: const Text("弹窗选择信息：SimpleDialog"),
            ), const SizedBox(height: 20),
            ElevatedButton(
              onPressed: _modelBottomSheet,
              child: const Text("底部弹窗：showModalBottomSheet"),
            ), const SizedBox(height: 20),
            ElevatedButton(
              onPressed: _toast, child: const Text("Toast"),
            ),
          ],
        ),
      ),
    );
  }
}

(6) routes.dart

import '../pages/tabs.dart';
import '../pages/dialog.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/dialog": (context) => const DialogPage(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

(7) setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

(8) category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

1-2 自定义Dialog

• 自定义Dialog需继承Dialog类，它所提供的child用于编写视图界面，可能达不到想要的效果。
• 因为默认的Dialog背景框是满屏展示的，如果想要完全自定义界面，就必须得重写build函数。

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - dialog.dart
  - routes/
    - routes.dart
  - widget/
    - myDialog.dart
- main.dart

(1) user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

(2) tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("自定义Dialog")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

(3) main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

(4) home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/dialog");
            },
            child: const Text("Dialog演示"),
          ),
        ],
      ),
    );
  }
}

(5) dialog.dart

import '../widget/myDialog.dart';
import 'package:flutter/material.dart';

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

  @override
  State<DialogPage> createState() => _DialogPageState();
}

class _DialogPageState extends State<DialogPage> {
  void _myDialog() async {
    // print("_myDialog");
    var result = await showDialog(
      // 点灰色背景，弹窗不消失
      barrierDismissible: false,
      context: context, builder: (context) {
        return MyDialog(
          title: "提示！",
          content:
            "采采流水，蓬蓬远春。窈窕深谷，时见美人。\n"
            "碧桃满树，风日水滨。柳阴路曲，流莺比邻。\n"
            "乘之愈往，识之愈真。如将不尽，与古为新。",
          opTap: () {
            print("关闭");
            Navigator.of(context).pop("关闭按钮事件");
          },
        );
    });
    print(result);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Dialog")),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              // 不加括号表示注册方法
              onPressed: _myDialog,
              // 加括号表示调用方法
              // onPressed: _myDialog(),
              child: const Text("自定义Dialog"),
            ),
          ],
        ),
      ),
    );
  }
}

(6) routes.dart

import '../pages/tabs.dart';
import '../pages/dialog.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/dialog": (context) => const DialogPage(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

(7) setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

(8) category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

(9) myDialog.dart

import 'package:flutter/material.dart';

// 继承Dialog类
class MyDialog extends Dialog {
  // 外部传值设置
  final String title;
  final String content;
  final Function()? opTap;

  const MyDialog({
    Key? key, required this.title, required this.content, required this.opTap
  }) : super(key: key);

  @override
  // 实现build方法
  Widget build(BuildContext context) {
    return Material(
      // 设置背景透明
      type: MaterialType.transparency,
      // 用于包裹组件，否则全屏展示
      child: Center(
        child: Container(
          height: 200, width: 300, color: Colors.white,
          child: Column(
            children: [
              Padding(
                padding: const EdgeInsets.all(10),
                child: Stack(
                  children: [
                    Align(
                      alignment: Alignment.centerLeft,
                      child: Text(title, style: const TextStyle(fontSize: 18)),
                    ),
                    Align(
                      alignment: Alignment.centerRight,
                      // child: Icon(Icons.close),
                      child: InkWell(
                        child: const Icon(Icons.close),
                        // onTap: () {print("close"); Navigator.pop(context);},
                        onTap: opTap,
                      ),
                    ),
                  ],
                ),
              ), const Divider(),
              Container(
                padding: const EdgeInsets.all(20),
                width: double.infinity,
                child: Text(content, style: const TextStyle(fontSize: 13)),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

2 PageView的使用

• Flutter中的轮动图以及上下滑页切换视频功能等，都可以通过PageView实现。
• 常见属性
  • children(配置子元素)、scrollDirection(Axis.horizonta水平方向，Axis.vertical垂直方向)。
  • onPageChanged(page改变的时候触发)、allowImpLicitScrolling(缓存当前页面的前后两页)。

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - pageView.dart
  - routes/
    - routes.dart
- main.dart

2-1 user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

2-2 tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("PageView的使用")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

2-3 main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

2-4 home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/pageView");
            },
            child: const Text("PageView演示"),
          ),
        ],
      ),
    );
  }
}

2-5 routes.dart

import '../pages/tabs.dart';
import '../pages/pageView.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/pageView": (context) => const PageViewPage(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

2-6 setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

2-7 category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

2-8 pageView.dart

import 'package:flutter/material.dart';

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

  @override
  State<PageViewPage> createState() => _PageViewPageState();
}

class _PageViewPageState extends State<PageViewPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("屏幕标题")),
      body: PageView(
        // 配置PageView垂直滑动，默认滑动方向是水平滑动
        scrollDirection: Axis.vertical,
        children: [
          Center(
            child: Text("第1屏", style: Theme.of(context).textTheme.headline1),
          ),
          Center(
            child: Text("第2屏", style: Theme.of(context).textTheme.headline1),
          ),
          Center(
            child: Text("第3屏", style: Theme.of(context).textTheme.headline1),
          ),
          Center(
            child: Text("第4屏", style: Theme.of(context).textTheme.headline1),
          ),
          Center(
            child: Text("第5屏", style: Theme.of(context).textTheme.headline1),
          ),
          Center(
            child: Text("第6屏", style: Theme.of(context).textTheme.headline1),
          ),
          Center(
            child: Text("第7屏", style: Theme.of(context).textTheme.headline1),
          ),
        ],
      ),
    );
  }
}

3 PageView.builder

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - pageViewBuilder.dart
  - routes/
    - routes.dart
- main.dart

3-1 user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

3-2 tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("PageView.builder")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

3-3 main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

3-4 home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/pageViewBuilder");
            },
            child: const Text("PageViewBuilder演示"),
          ),
        ],
      ),
    );
  }
}

3-5 routes.dart

import '../pages/tabs.dart';
import '../pages/pageViewBuilder.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/pageViewBuilder": (context) => const PageViewBuilderPage(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

3-6 setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

3-7 category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

3-8 pageViewBuilder.dart

import 'package:flutter/material.dart';

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

  @override
  State<PageViewBuilderPage> createState() => _PageViewBuilderPageState();
}

class _PageViewBuilderPageState extends State<PageViewBuilderPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("屏幕标题")),
      body: PageView.builder(
        // 垂直
        scrollDirection: Axis.vertical,
        itemCount: 10,
        itemBuilder: (context, index) {
          return Center(
            child: Text("第${index+1}层", style: Theme.of(context).textTheme.headline1),
          );
        },
      ),
    );
  }
}

4 实现上拉无限加载

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - pageViewFullPage.dart
  - routes/
    - routes.dart
- main.dart

4-1 user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

4-2 tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("实现上拉无限加载")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

4-3 main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

4-4 home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/pageViewFullPage");
            },
            child: const Text("PageView上拉无限加载演示"),
          ),
        ],
      ),
    );
  }
}

4-5 routes.dart

import '../pages/tabs.dart';
import '../pages/pageViewFullPage.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/pageViewFullPage": (context) => const PageViewFullPage(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

4-6 setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

4-7 category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

4-8 pageViewFullPage.dart

import 'package:flutter/material.dart';

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

  @override
  State<PageViewFullPage> createState() => _PageViewFullPageState();
}

class _PageViewFullPageState extends State<PageViewFullPage> {
  List<Widget> list=[];

  @override
  void initState() {
    super.initState();
    for(var i=0; i<10; i++) {
      list.add(
        Center(
          child: Text("第${i+1}屏", style: const TextStyle(fontSize: 60)),
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("屏幕标题")),
      body: PageView(
        scrollDirection: Axis.vertical,
        onPageChanged: (index) {
          print(index);
          if(index+2==list.length) {
            setState(() {
              for(var i=0; i<10; i++) {
                list.add(
                  Center(
                    child: Text("第${i+1}屏", style: const TextStyle(fontSize: 60)),
                  ),
                );
              }
            });
          }
        },
        children: list,
      ),
    );
  }
}

5 实现图片无限轮播

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - pageViewSwiper.dart
- routes/
  - routes.dart
- widget/
  - image.dart
- main.dart

5-1 user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

5-2 tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("实现图片无限轮播")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

5-3 main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

5-4 home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/pageViewSwiper");
            },
            child: const Text("PageViewSwiper"),
          ),
        ],
      ),
    );
  }
}

5-5 image.dart

import 'package:flutter/material.dart';

class ImagePage extends StatelessWidget {
  final double width; final double height; final String src;

  const ImagePage({
    Key? key, this.width=double.infinity, this.height=200, required this.src
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: width,
      height: height,
      child: Image.network(src, fit: BoxFit.cover),
    );
  }
}

5-6 routes.dart

import '../pages/tabs.dart';
import '../pages/pageViewSwiper.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/pageViewSwiper": (context) => const PageViewSwiper(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

5-7 setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

5-8 category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

5-9 pageViewSwiper.dart

import '../widget/image.dart';
import 'package:flutter/material.dart';

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

  @override
  State<PageViewSwiper> createState() => _PageViewSwiperState();
}

class _PageViewSwiperState extends State<PageViewSwiper> {
  List<Widget> list=[]; int _currentIndex=0;

  @override
  void initState() {
    super.initState();
    list = const [
      ImagePage(src: "https://t.hk.uy/b8Rq"),
      ImagePage(src: "https://t.hk.uy/b8Rr"),
      ImagePage(src: "https://t.hk.uy/b8Rs"),
      ImagePage(src: "https://t.hk.uy/b8Rt"),
      ImagePage(src: "https://t.hk.uy/b8Ru"),
      ImagePage(src: "https://t.hk.uy/b8Rv"),
    ];
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("PageViewSwiper")),
      body: Stack(
        children: [
          SizedBox(
            height: 630,
            child: PageView.builder(
              onPageChanged: (index) {
                // 刚开始   _currentIndex=0
                setState(() {
                  // index=1---1 ... index=6---0
                  _currentIndex=index % list.length;    
                });
              },
              itemCount: 1000,
              // index值为0-1000
              itemBuilder: (context, index) {
                return list[index%list.length];
              },
            ),
          ),
          Positioned(
            // left和right为0，占满整行
            left: 0, right: 0, bottom: 2,
            child: Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: List.generate(list.length, (index) {
                return Container(
                  margin: const EdgeInsets.all(5),
                  width: 10, height: 10,
                  decoration: BoxDecoration(
                    color: _currentIndex==index?Colors.white:Colors.grey,
                    // 同borderRadius
                    shape: BoxShape.circle,
                    // borderRadius: BorderRadius.circular(5),
                  ),
                );
              }).toList(),
            ),
          ),
        ],
      ),
    );
  }
}

6 Flutter实现定时器

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - pageViewSwiper.dart
  - routes/
    - routes.dart
  - widget/
    - swiper.dart
- main.dart

6-1 user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

6-2 tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Flutter实现定时器")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

6-3 main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

6-4 home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/pageViewSwiper");
            },
            child: const Text("PageViewSwiper"),
          ),
        ],
      ),
    );
  }
}

6-5 routes.dart

import '../pages/tabs.dart';
import '../pages/pageViewSwiper.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/pageViewSwiper": (context) => const PageViewSwiper(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

6-6 swiper.dart

import 'package:flutter/material.dart';

class Swiper extends StatefulWidget {
  final double width; final double height; final List<String> list;
  const Swiper({
    Key? key, this.width=double.infinity, this.height=200, required this.list
  }) : super(key: key);

  @override
  State<Swiper> createState() => _SwiperState();
}

class _SwiperState extends State<Swiper> {
  int _currentIndex=0;
  List<Widget> pageList=[];

  @override
  void initState() {
    super.initState();
    for(var i=0; i<widget.list.length; i++) {
      pageList.add(
        ImagePage(
          width: widget.width, height: widget.height, src: widget.list[i],
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        SizedBox(
          height: 605,
          child: PageView.builder(
            onPageChanged: (index) {
              // 刚开始   _currentIndex=0
              setState(() {
                // index=1---1 ... index=6---0
                _currentIndex=index % pageList.length;  
              });
            },
            itemCount: 1000,
            // index值为0-1000
            itemBuilder: (context, index) {
              return pageList[index % pageList.length];
            },
          ),
        ),
        Positioned(
          // left和right为0，占满整行
          left: 0, right: 0, bottom: 2,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: List.generate(pageList.length, (index) {
              return Container(
                margin: const EdgeInsets.all(5),
                width: 10, height: 10,
                decoration: BoxDecoration(
                  color: _currentIndex==index?Colors.white:Colors.grey,
                  // 同borderRadius
                  shape: BoxShape.circle,
                  // borderRadius: BorderRadius.circular(5),
                ),
              );
            }).toList(),
          ),
        ),
      ],
    );
  }
}

class ImagePage extends StatelessWidget {
  final double width; final double height; final String src;
  const ImagePage({
    Key? key, this.width=double.infinity, this.height=200, required this.src
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: width,
      height: height,
      child: Image.network(src, fit: BoxFit.cover),
    );
  }
}

6-7 setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

6-8 category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

6-9 pageViewSwiper.dart

import 'dart:async';
import '../widget/swiper.dart';
import 'package:flutter/material.dart';

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

  @override
  State<PageViewSwiper> createState() => _PageViewSwiperState();
}

class _PageViewSwiperState extends State<PageViewSwiper> {
  // List<Widget> list=[];
  List<String> list=[];

  @override
  void initState() {
    super.initState();
    list = const [
      "https://t.hk.uy/b8Rq", "https://t.hk.uy/b8Rr",
      "https://t.hk.uy/b8Rs", "https://t.hk.uy/b8Rt",
      "https://t.hk.uy/b8Ru", "https://t.hk.uy/b8Rv",
      // ImagePage(src: "https://t.hk.uy/b8Rq"),
      // ImagePage(src: "https://t.hk.uy/b8Rr"),
      // ImagePage(src: "https://t.hk.uy/b8Rs"),
      // ImagePage(src: "https://t.hk.uy/b8Rt"),
      // ImagePage(src: "https://t.hk.uy/b8Ru"),
      // ImagePage(src: "https://t.hk.uy/b8Rv"),
    ];
    // 创建定时器，每隔3秒钟打印一句“执行”
    Timer t=Timer.periodic(const Duration(seconds: 3), (timer) {
      print("执行");
      // timer.cancel();
    });
    // t.cancel();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("PageViewSwiper")),
      body: ListView(
        children: [
          Swiper(list: list)
        ],
      ),
    );
  }
}

7 实现图片动态轮播

# myflutter(项目名)目录结构如下
- pages/
  - tabs/
    - user.dart
    - home.dart
    - setting.dart
    - category.dart
  - tabs.dart
  - pageViewSwiper.dart
  - routes/
    - routes.dart
  - widget/
    - swiper.dart
- main.dart

7-1 user.dart

import 'package:flutter/material.dart';

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

  @override
  State<UserPage> createState() => _UserPageState();
}

class _UserPageState extends State<UserPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("用户信息"),
    );
  }
}

7-2 tabs.dart

import './tabs/user.dart';
import './tabs/home.dart';
import './tabs/setting.dart';
import './tabs/category.dart';
import 'package:flutter/material.dart';

class Tabs extends StatefulWidget {
  final int index;
  const Tabs({Key? key, this.index=0}) : super(key: key);

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  late int _currentIndex;
  @override
  void initState() {
    super.initState();
    _currentIndex=widget.index;
  }
  final List<Widget> _pages = const [
    HomePage(), CategoryPage(), SettingPage(), UserPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("实现图片动态轮播")),
      body: _pages[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        // 选中的颜色
        fixedColor: Colors.red,
        // 配置底部菜单大小
        iconSize: 40,
        // 4个以上菜单需配置此项
        type: BottomNavigationBarType.fixed,
        // 默认选中分类(第二个)
        // currentIndex: 1,
        currentIndex: _currentIndex,
        onTap: (index){
          // 获取点击的索引值
          // print(index);
          // 注意调用setState
          setState(() {
            _currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon:Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon:Icon(Icons.settings),
            label: "设置",
          ),
          // 没有type菜单图标会被挤掉
          BottomNavigationBarItem(
            icon:Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}

7-3 main.dart

import './routes/routes.dart';
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // 去掉右上角debug图标
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        // 全局配置主题
        appBarTheme: const AppBarTheme(
          // 主题标题全部居中显示
          centerTitle: true
        ),
      ),
      // home: const Tabs(),
      // 初始化路由
      initialRoute: "/",
      // 固定写法，配置onGenerateRoute
      onGenerateRoute: onGenerateRoute,
    );
  }
}

7-4 home.dart

import 'package:flutter/material.dart';

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          ElevatedButton(
            onPressed: () {
              Navigator.pushNamed(context, "/pageViewSwiper");
            },
            child: const Text("PageViewSwiper"),
          ),
        ],
      ),
    );
  }
}

7-5 routes.dart

import '../pages/tabs.dart';
import '../pages/pageViewSwiper.dart';
// 配置iOS风格的路由，引入库
import 'package:flutter/cupertino.dart';
// import 'package:flutter/material.dart';

// 定义一个Map类型的路由
Map routes = {
  "/": (context) => const Tabs(),
  "/pageViewSwiper": (context) => const PageViewSwiper(),
};

// 配置onGenerateRoute，固定写法，该方法相当于一个中间件，可以做权限判断
// ignore: prefer_function_declarations_over_variables
var onGenerateRoute = (RouteSettings settings) {
  // 统一处理
  final String? name = settings.name;
  final Function? pageContentBuilder = routes[name];
  if (pageContentBuilder != null) {
    if (settings.arguments != null) {
      // final Route route = MaterialPageRoute(
      // 替换MaterialPageRoute
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(
          context, arguments: settings.arguments
        )
      );
      return route;
    } else {
      // final Route route = MaterialPageRoute(
      final Route route = CupertinoPageRoute(
        builder: (context) => pageContentBuilder(context)
      );
      return route;
    }
  }
  return null;
};

7-6 swiper.dart

import 'dart:async';
import 'package:flutter/material.dart';

class Swiper extends StatefulWidget {
  final double width; final double height; final List<String> list;
  const Swiper({
    Key? key, this.width=double.infinity, this.height=200, required this.list
  }) : super(key: key);

  @override
  State<Swiper> createState() => _SwiperState();
}

class _SwiperState extends State<Swiper> {
  int _currentIndex=0;
  List<Widget> pageList=[];
  late PageController _pageController;
  late Timer timer;

  @override
  void initState() {
    super.initState();
    // 数据
    for(var i=0; i<widget.list.length; i++) {
      pageList.add(
        ImagePage(
          width: widget.width, height: widget.height, src: widget.list[i],
        ),
      );
    }
    // PageController
    _pageController=PageController(initialPage: 0);
    timer = Timer.periodic(const Duration(seconds: 5), (t) {
      // 实现图片5秒动态轮播
      _pageController.animateToPage(
        (_currentIndex+1)%pageList.length,
        duration: const Duration(milliseconds: 200),
        curve: Curves.linear,
      );
    });
  }
  @override
  void dispose() {
    super.dispose();
    timer.cancel();
    _pageController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        SizedBox(
          height: 605,
          child: PageView.builder(
            controller: _pageController,
            onPageChanged: (index) {
              // 刚开始   _currentIndex=0
              setState(() {
                // index=1---1 ... index=6---0
                _currentIndex=index % pageList.length;  
              });
            },
            itemCount: 1000,
            // index值为0-1000
            itemBuilder: (context, index) {
              return pageList[index % pageList.length];
            },
          ),
        ),
        Positioned(
          // left和right为0，占满整行
          left: 0, right: 0, bottom: 2,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: List.generate(pageList.length, (index) {
              return Container(
                margin: const EdgeInsets.all(5),
                width: 10, height: 10,
                decoration: BoxDecoration(
                  color: _currentIndex==index?Colors.white:Colors.grey,
                  // 同borderRadius
                  shape: BoxShape.circle,
                  // borderRadius: BorderRadius.circular(5),
                ),
              );
            }).toList(),
          ),
        ),
      ],
    );
  }
}

class ImagePage extends StatelessWidget {
  final double width; final double height; final String src;
  const ImagePage({
    Key? key, this.width=double.infinity, this.height=200, required this.src
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: width,
      height: height,
      child: Image.network(src, fit: BoxFit.cover),
    );
  }
}

7-7 setting.dart

import 'package:flutter/material.dart';

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

  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("系统设置"),
    );
  }
}

7-8 category.dart

import 'package:flutter/material.dart';

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

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Text("分类页面"),
    );
  }
}

7-9 pageViewSwiper.dart

import 'dart:async';
import '../widget/swiper.dart';
import 'package:flutter/material.dart';

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

  @override
  State<PageViewSwiper> createState() => _PageViewSwiperState();
}

class _PageViewSwiperState extends State<PageViewSwiper> {
  // List<Widget> list=[];
  List<String> list=[];

  @override
  void initState() {
    super.initState();
    list = const [
      "https://t.hk.uy/b8Rq", "https://t.hk.uy/b8Rr",
      "https://t.hk.uy/b8Rs", "https://t.hk.uy/b8Rt",
      "https://t.hk.uy/b8Ru", "https://t.hk.uy/b8Rv",
      // ImagePage(src: "https://t.hk.uy/b8Rq"),
      // ImagePage(src: "https://t.hk.uy/b8Rr"),
      // ImagePage(src: "https://t.hk.uy/b8Rs"),
      // ImagePage(src: "https://t.hk.uy/b8Rt"),
      // ImagePage(src: "https://t.hk.uy/b8Ru"),
      // ImagePage(src: "https://t.hk.uy/b8Rv"),
    ];
    // 创建定时器，每隔3秒钟打印一句“执行”
    Timer t=Timer.periodic(const Duration(seconds: 3), (timer) {
      print("执行");
      // timer.cancel();
    });
    // t.cancel();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("PageViewSwiper")),
      body: ListView(
        children: [
          Swiper(list: list)
        ],
      ),
    );
  }
}

8 缓存PageView页面