flutter3-dart-chat：基于flutter3+material-ui仿微信App聊天应用

距离2024新春佳节还有3天时间，趁着佳节来临之际，使用全新跨多平台技术flutter3+dart3开发了一款仿微信App聊天界面实例项目Flutter3Chat。

flutter3-wchat 实现发送图文emoj表情消息+gif动图、长按仿微信语音操作面板、图片预览、红包及朋友圈等功能。

技术栈

• 开发工具：VScode
• 框架技术：Flutter3.16.5+Dart3.2.3
• UI组件库：Material-Design3
• 弹窗组件：showDialog/showModalBottomSheet/AlertDialog
• 图片预览：photo_view^0.14.0
• 缓存技术：shared_preferences^2.2.2
• 下拉刷新：easy_refresh^3.3.4
• toast提示：toast^0.3.0
• 网址拉起：url_launcher^6.2.4

目前使用flutter开发的项目支持编译到全平台android/ios/macos/linux/windows/web，可以说是前景非常广大的。

项目目录结构

通过flutter create app_proj命令即可快速创建一个多平台项目。

不过在开发之前，需要先配置好flutter开发环境。大家去官网根据步骤一步一步配置即可。

https://flutter.dev/
https://flutter.cn/
https://pub.flutter-io.cn/
https://www.dartcn.com/

如果使用vscode开发项目，可安装扩展插件。

flutter入口配置

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:toast/toast.dart';

// 引入公共样式
import 'styles/index.dart';

// 引入底部tabbar
import 'components/tabbar.dart';

// 引入路由管理
import 'router/index.dart';

// 错误模块
import '../views/error/index.dart';

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

DateTime? lastPopTime;

class MyApp extends StatelessWidget {
    const MyApp({ super.key });

  // 退出app提示
  Future appOnPopInvoked(didPop) async {
    if(lastPopTime == null || DateTime.now().difference(lastPopTime!) > const Duration(seconds: 2)) {
      lastPopTime = DateTime.now();
      Toast.show('再按一次退出应用');
      return false;
    }
    SystemNavigator.pop();
    return true;
  }
  
    @override
    Widget build(BuildContext context){
    ToastContext().init(context);

        return MaterialApp(
            title: 'Flutter Chat',
            debugShowCheckedModeBanner: false,
            theme: ThemeData(
                primaryColor: FStyle.primaryColor,
                useMaterial3: true,
        // windows桌面端字体粗细不一样
        fontFamily: Platform.isWindows ? 'Microsoft YaHei' : null,
            ),
            // home: const FTabBar(),
      home: PopScope(
        // canPop: false,
        onPopInvoked: appOnPopInvoked,
        child: const FTabBar(),
      ),
      // 初始路由
      // initialRoute: '/',
      // 自定义路由
            onGenerateRoute: onGenerateRoute,
      // 错误路由
      onUnknownRoute: (settings) {
        return MaterialPageRoute(builder: (context) => const Error());
      },
        );
    }
}

flutter表单验证60s倒计时/圆角/渐变按钮

Timer? timer;
String vcodeText = '获取验证码';
bool disabled = false;
int time = 60;

// 60s倒计时
void handleVcode() {
  if(authObj['tel'] == '') {
    snackbar('手机号不能为空');
  }else if(!Utils.checkTel(authObj['tel'])) {
    snackbar('手机号格式不正确');
  }else {
    setState(() {
      disabled = true;
    });
    startTimer();
  }
}
startTimer() {
  timer = Timer.periodic(const Duration(seconds: 1), (timer) {
    setState(() {
      if(time > 0) {
        vcodeText = '获取验证码(${time--})';
      }else {
        vcodeText = '获取验证码';
        time = 60;
        disabled = false;
        timer.cancel();
      }
    });
  });
  snackbar('短信验证码已发送，请注意查收', color: Colors.green);
}

• Container和TextField组件配合实现圆角文本框

Container(
  height: 40.0,
  margin: const EdgeInsets.symmetric(vertical: 5.0, horizontal: 30.0),
  decoration: BoxDecoration(
    color: Colors.white,
    border: Border.all(color: const Color(0xffdddddd)),
    borderRadius: BorderRadius.circular(15.0),
  ),
  child: Row(
    children: [
      Expanded(
        child: TextField(
          keyboardType: TextInputType.phone,
          controller: fieldController,
          decoration: InputDecoration(
            hintText: '输入手机号',
            suffixIcon: Visibility(
              visible: authObj['tel'].isNotEmpty,
              child: InkWell(
                hoverColor: Colors.transparent,
                highlightColor: Colors.transparent,
                splashColor: Colors.transparent,
                onTap: handleClear,
                child: const Icon(Icons.clear, size: 16.0,),
              )
            ),
            contentPadding: const EdgeInsets.symmetric(vertical: 0, horizontal: 12.0),
            border: const OutlineInputBorder(borderSide: BorderSide.none),
          ),
          onChanged: (value) {
            setState(() {
              authObj['tel'] = value;
            });
          },
        ),
      )
    ],
  ),
),

• Container提供的gradient实现渐变色

Container(
  margin: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 30.0),
  decoration: BoxDecoration(
    borderRadius: BorderRadius.circular(15.0),
    // 自定义按钮渐变色
    gradient: const LinearGradient(
      begin: Alignment.topLeft,
      end: Alignment.bottomRight,
      colors: [
        Color(0xFF0091EA), Color(0xFF07C160)
      ],
    )
  ),
  child: SizedBox(
    width: double.infinity,
    height: 45.0,
    child: FilledButton(
      style: ButtonStyle(
        backgroundColor: MaterialStateProperty.all(Colors.transparent),
        shadowColor: MaterialStateProperty.all(Colors.transparent),
        shape: MaterialStatePropertyAll(
          RoundedRectangleBorder(borderRadius: BorderRadius.circular(15.0))
        )
      ),
      onPressed: handleSubmit,
      child: const Text('登录', style: TextStyle(fontSize: 18.0),),
    ),
  )
),

flutter3渐变色导航条

如何在flutter中导航条实现渐变背景呢，由于AppBar提供的background属性只能设置颜色，不能设置渐变。只能通过flexibleSpace可伸缩灵活属性实现功能。

AppBar(
  title: Text('Flutter3-Chat'),
  flexibleSpace: Container(
    decoration: const BoxDecoration(
      gradient: LinearGradient(
        begin: Alignment.topLeft,
        end: Alignment.bottomRight,
        colors: [
          Color(0xFF0091EA), Color(0xFF07C160)
        ],
      )
    ),
  )
),

flutter实现微信下拉菜单/长按菜单

PopupMenuButton(
  icon: FStyle.iconfont(0xe62d, size: 17.0),
  offset: const Offset(0, 50.0),
  tooltip: '',
  color: const Color(0xFF353535),
  itemBuilder: (BuildContext context) {
    return [
      popupMenuItem(0xe666, '发起群聊', 0),
      popupMenuItem(0xe75c, '添加朋友', 1),
      popupMenuItem(0xe603, '扫一扫', 2),
      popupMenuItem(0xe6ab, '收付款', 3),
    ];
  },
  onSelected: (value) {
    switch(value) {
      case 0:
        print('发起群聊');
        break;
      case 1:
        Navigator.pushNamed(context, '/addfriends');
        break;
      case 2:
        print('扫一扫');
        break;
      case 3:
        print('收付款');
        break;
    }
  },
)

// 下拉菜单项
static popupMenuItem(int codePoint, String title, value) {
  return PopupMenuItem(
    value: value,
    child: Row(
      mainAxisAlignment: MainAxisAlignment.start,
      children: [
        const SizedBox(width: 10.0,),
        FStyle.iconfont(codePoint, size: 21.0, color: Colors.white),
        const SizedBox(width: 10.0,),
        Text(title, style: const TextStyle(fontSize: 16.0, color: Colors.white),),
      ],
    ),
  );
}

// 长按坐标点
double posDX = 0.0;
double posDY = 0.0;

// 长按菜单
void showContextMenu(BuildContext context) {
  bool isLeft = posDX > MediaQuery.of(context).size.width / 2 ? false : true;
  bool isTop = posDY > MediaQuery.of(context).size.height / 2 ? false : true;

  showDialog(
    context: context,
    barrierColor: Colors.transparent, // 遮罩透明
    builder: (context) {
      return Stack(
        children: [
          Positioned(
            top: isTop ? posDY : posDY - 135,
            left: isLeft ? posDX : posDX - 135,
            width: 135,
            child: Material(
              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(2.0)),
              color: Colors.white,
              elevation: 3.0,
              clipBehavior: Clip.hardEdge,
              child: Column(
                children: [
                  ListTile(
                    title: const Text('标为未读', style: TextStyle(color: Colors.black87,),),
                    dense: true,
                    onTap: () {},
                  ),
                  ListTile(
                    title: const Text('置顶该聊天', style: TextStyle(color: Colors.black87,),),
                    dense: true,
                    onTap: () {},
                  ),
                  ListTile(
                    title: const Text('不显示该聊天', style: TextStyle(color: Colors.black87,),),
                    dense: true,
                    onTap: () {},
                  ),
                  ListTile(
                    title: const Text('删除', style: TextStyle(color: Colors.black87,),),
                    dense: true,
                    onTap: () {},
                  )
                ],
              ),
            ),
          )
        ],
      );
    },
  );
}

flutter3微信朋友圈九宫格

GroupZone(images: item['images']),

GroupZone(
  images: uploadList,
  album: true,
  onChoose: () async {
    Toast.show('选择手机相册图片', duration: 2, gravity: 1);
  },
),

// 创建可点击预览图片
createImage(BuildContext context, String img, int key) {
  return GestureDetector(
    child: Hero(
      tag: img, // 放大缩小动画效果标识
      child: img == '+' ? 
      Container(color: Colors.transparent, child: const Icon(Icons.add, size: 30.0, color: Colors.black45),)
      :
      Image.asset(
        img,
        width: width,
        fit: BoxFit.contain,
      ),
    ),
    onTap: () {
      // 选择图片
      if(img == '+') {
        onChoose!();
      }else {
        Navigator.of(context).push(FadeRoute(route: ImageViewer(
          images: album ? imgList!.sublist(0, imgList!.length - 1) : imgList,
          index: key,
        )));
      }
    },
  );
}

flutter3聊天实现

文本框TextField设置maxLines: null即可实现多行文本输入。

// 输入框
Offstage(
  offstage: voiceBtnEnable,
  child: TextField(
    decoration: const InputDecoration(
      isDense: true,
      hoverColor: Colors.transparent,
      contentPadding: EdgeInsets.all(8.0),
      border: OutlineInputBorder(borderSide: BorderSide.none),
    ),
    style: const TextStyle(fontSize: 16.0,),
    maxLines: null,
    controller: editorController,
    focusNode: editorFocusNode,
    cursorColor: const Color(0xFF07C160),
    onChanged: (value) {},
  ),
),

// 语音
Offstage(
  offstage: !voiceBtnEnable,
  child: GestureDetector(
    child: Container(
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(5),
      ),
      alignment: Alignment.center,
      height: 40.0,
      width: double.infinity,
      child: Text(voiceTypeMap[voiceType], style: const TextStyle(fontSize: 15.0),),
    ),
    onPanStart: (details) {
      setState(() {
        voiceType = 1;
        voicePanelEnable = true;
      });
    },
    onPanUpdate: (details) {
      Offset pos = details.globalPosition;
      double swipeY = MediaQuery.of(context).size.height - 120;
      double swipeX = MediaQuery.of(context).size.width / 2 + 50;
      setState(() {
        if(pos.dy >= swipeY) {
          voiceType = 1; // 松开发送
        }else if (pos.dy < swipeY && pos.dx < swipeX) {
          voiceType = 2; // 左滑松开取消
        }else if (pos.dy < swipeY && pos.dx >= swipeX) {
          voiceType = 3; // 右滑语音转文字
        }
      });
    },
    onPanEnd: (details) {
      // print('停止录音');
      setState(() {
        switch(voiceType) {
          case 1:
            Toast.show('发送录音文件', duration: 1, gravity: 1);
            voicePanelEnable = false;
            break;
          case 2:
            Toast.show('取消发送', duration: 1, gravity: 1);
            voicePanelEnable = false;
            break;
          case 3:
            Toast.show('语音转文字', duration: 1, gravity: 1);
            voicePanelEnable = true;
            voiceToTransfer = true;
            break;
        }
        voiceType = 0;
      });
    },
  ),
),

好了，综上就是flutter3+dart3开发跨端聊天App实例的一些分享。

https://segmentfault.com/a/1190000044519351
https://segmentfault.com/a/1190000044418592