flutter_chat_ui 1.3.4

Actively maintained, community-driven chat UI implementation with an optional Firebase BaaS.

example/lib/main.dart

import 'dart:convert';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show rootBundle;
import 'package:flutter_chat_types/flutter_chat_types.dart' as types;
import 'package:flutter_chat_ui/flutter_chat_ui.dart';
import 'package:image_picker/image_picker.dart';
import 'package:intl/date_symbol_data_local.dart';
import 'package:mime/mime.dart';
import 'package:open_file/open_file.dart';
import 'package:uuid/uuid.dart';

void main() {
  initializeDateFormatting().then((_) => runApp(const MyApp()));
}

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: ChatPage(),
    );
  }
}

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

  @override
  _ChatPageState createState() => _ChatPageState();
}

class _ChatPageState extends State<ChatPage> {
  List<types.Message> _messages = [];
  final _user = const types.User(id: '06c33e8b-e835-4736-80f4-63f44b66666c');

  @override
  void initState() {
    super.initState();
    _loadMessages();
  }

  void _addMessage(types.Message message) {
    setState(() {
      _messages.insert(0, message);
    });
  }

  void _handleAtachmentPressed() {
    showModalBottomSheet<void>(
      context: context,
      builder: (BuildContext context) {
        return SafeArea(
          child: SizedBox(
            height: 144,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: <Widget>[
                TextButton(
                  onPressed: () {
                    Navigator.pop(context);
                    _handleImageSelection();
                  },
                  child: const Align(
                    alignment: Alignment.centerLeft,
                    child: Text('Photo'),
                  ),
                ),
                TextButton(
                  onPressed: () {
                    Navigator.pop(context);
                    _handleFileSelection();
                  },
                  child: const Align(
                    alignment: Alignment.centerLeft,
                    child: Text('File'),
                  ),
                ),
                TextButton(
                  onPressed: () => Navigator.pop(context),
                  child: const Align(
                    alignment: Alignment.centerLeft,
                    child: Text('Cancel'),
                  ),
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  void _handleFileSelection() async {
    final result = await FilePicker.platform.pickFiles(
      type: FileType.any,
    );

    if (result != null) {
      final message = types.FileMessage(
        author: _user,
        createdAt: DateTime.now().millisecondsSinceEpoch,
        id: const Uuid().v4(),
        mimeType: lookupMimeType(result.files.single.path),
        name: result.files.single.name,
        size: result.files.single.size,
        uri: result.files.single.path,
      );

      _addMessage(message);
    }
  }

  void _handleImageSelection() async {
    final result = await ImagePicker().pickImage(
      imageQuality: 70,
      maxWidth: 1440,
      source: ImageSource.gallery,
    );

    if (result != null) {
      final bytes = await result.readAsBytes();
      final image = await decodeImageFromList(bytes);

      final message = types.ImageMessage(
        author: _user,
        createdAt: DateTime.now().millisecondsSinceEpoch,
        height: image.height.toDouble(),
        id: const Uuid().v4(),
        name: result.name,
        size: bytes.length,
        uri: result.path,
        width: image.width.toDouble(),
      );

      _addMessage(message);
    }
  }

  void _handleMessageTap(types.Message message) async {
    if (message is types.FileMessage) {
      await OpenFile.open(message.uri);
    }
  }

  void _handlePreviewDataFetched(
    types.TextMessage message,
    types.PreviewData previewData,
  ) {
    final index = _messages.indexWhere((element) => element.id == message.id);
    final updatedMessage = _messages[index].copyWith(previewData: previewData);

    WidgetsBinding.instance?.addPostFrameCallback((_) {
      setState(() {
        _messages[index] = updatedMessage;
      });
    });
  }

  void _handleSendPressed(types.PartialText message) {
    final textMessage = types.TextMessage(
      author: _user,
      createdAt: DateTime.now().millisecondsSinceEpoch,
      id: const Uuid().v4(),
      text: message.text,
    );

    _addMessage(textMessage);
  }

  void _loadMessages() async {
    final response = await rootBundle.loadString('assets/messages.json');
    final messages = (jsonDecode(response) as List)
        .map((e) => types.Message.fromJson(e as Map<String, dynamic>))
        .toList();

    setState(() {
      _messages = messages;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        bottom: false,
        child: Chat(
          messages: _messages,
          onAttachmentPressed: _handleAtachmentPressed,
          onMessageTap: _handleMessageTap,
          onPreviewDataFetched: _handlePreviewDataFetched,
          onSendPressed: _handleSendPressed,
          user: _user,
        ),
      ),
    );
  }
}