flutter-samples/packages/stream_chat_v1/lib/channel_list.dart

import 'dart:async';

import 'package:example/localizations.dart';
import 'package:example/routes/routes.dart';
import 'package:example/search_text_field.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:stream_chat_flutter/stream_chat_flutter.dart';

import 'channel_page.dart';
import 'chat_info_screen.dart';
import 'group_info_screen.dart';

class ChannelList extends StatefulWidget {
  @override
  _ChannelList createState() => _ChannelList();
}

class _ChannelList extends State<ChannelList> {
  ScrollController _scrollController = ScrollController();

  TextEditingController? _controller;

  String _channelQuery = '';

  bool _isSearchActive = false;

  Timer? _debounce;

  void _channelQueryListener() {
    if (_debounce?.isActive ?? false) _debounce!.cancel();
    _debounce = Timer(const Duration(milliseconds: 350), () {
      if (mounted) {
        setState(() {
          _channelQuery = _controller!.text;
          _isSearchActive = _channelQuery.isNotEmpty;
        });
      }
    });
  }

  @override
  void initState() {
    super.initState();
    _controller = TextEditingController()..addListener(_channelQueryListener);
  }

  @override
  void dispose() {
    _controller?.removeListener(_channelQueryListener);
    _controller?.dispose();
    _scrollController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final user = StreamChat.of(context).currentUser;
    return WillPopScope(
      onWillPop: () async {
        if (_isSearchActive) {
          _controller!.clear();
          setState(() => _isSearchActive = false);
          return false;
        }
        return true;
      },
      child: NotificationListener<ScrollUpdateNotification>(
        onNotification: (ScrollNotification scrollInfo) {
          if (_scrollController.position.userScrollDirection ==
              ScrollDirection.reverse) {
            FocusScope.of(context).unfocus();
          }
          return true;
        },
        child: NestedScrollView(
          controller: _scrollController,
          floatHeaderSlivers: false,
          headerSliverBuilder: (_, __) => [
            SliverToBoxAdapter(
              child: SearchTextField(
                controller: _controller,
                showCloseButton: _isSearchActive,
                hintText: AppLocalizations.of(context).search,
              ),
            ),
          ],
          body: MessageSearchBloc(
            child: _isSearchActive
                ? MessageSearchListView(
                    showErrorTile: true,
                    messageQuery: _channelQuery,
                    filters: Filter.in_('members', [user!.id]),
                    sortOptions: [
                      SortOption(
                        'created_at',
                        direction: SortOption.ASC,
                      ),
                    ],
                    pullToRefresh: false,
                    limit: 30,
                    emptyBuilder: (_) {
                      return LayoutBuilder(
                        builder: (context, viewportConstraints) {
                          return SingleChildScrollView(
                            physics: AlwaysScrollableScrollPhysics(),
                            child: ConstrainedBox(
                              constraints: BoxConstraints(
                                minHeight: viewportConstraints.maxHeight,
                              ),
                              child: Center(
                                child: Column(
                                  children: [
                                    Padding(
                                      padding: const EdgeInsets.all(24),
                                      child: StreamSvgIcon.search(
                                        size: 96,
                                        color: Colors.grey,
                                      ),
                                    ),
                                    Text(
                                      AppLocalizations.of(context).noResults,
                                    ),
                                  ],
                                ),
                              ),
                            ),
                          );
                        },
                      );
                    },
                    onItemTap: (messageResponse) async {
                      FocusScope.of(context).requestFocus(FocusNode());
                      final client = StreamChat.of(context).client;
                      final message = messageResponse.message;
                      final channel = client.channel(
                        messageResponse.channel!.type,
                        id: messageResponse.channel!.id,
                      );
                      if (channel.state == null) {
                        await channel.watch();
                      }
                      Navigator.pushNamed(
                        context,
                        Routes.CHANNEL_PAGE,
                        arguments: ChannelPageArgs(
                          channel: channel,
                          initialMessage: message,
                        ),
                      );
                    },
                  )
                : ChannelListView(
                    onChannelTap: (channel, _) {
                      Navigator.pushNamed(
                        context,
                        Routes.CHANNEL_PAGE,
                        arguments: ChannelPageArgs(
                          channel: channel,
                        ),
                      );
                    },
                    onStartChatPressed: () {
                      Navigator.pushNamed(context, Routes.NEW_CHAT);
                    },
                    swipeToAction: true,
                    filter: Filter.in_('members', [user!.id]),
                    presence: true,
                    limit: 30,
                    onViewInfoTap: (channel) {
                      Navigator.pop(context);
                      if (channel.memberCount == 2 && channel.isDistinct) {
                        Navigator.push(
                          context,
                          MaterialPageRoute(
                            builder: (context) => StreamChannel(
                              channel: channel,
                              child: ChatInfoScreen(
                                messageTheme:
                                    StreamChatTheme.of(context).ownMessageTheme,
                                user: channel.state!.members
                                    .where((m) =>
                                        m.userId !=
                                        channel.client.state.currentUser!.id)
                                    .first
                                    .user,
                              ),
                            ),
                          ),
                        );
                      } else {
                        Navigator.push(
                          context,
                          MaterialPageRoute(
                            builder: (context) => StreamChannel(
                              channel: channel,
                              child: GroupInfoScreen(
                                messageTheme:
                                    StreamChatTheme.of(context).ownMessageTheme,
                              ),
                            ),
                          ),
                        );
                      }
                    },
                  ),
          ),
        ),
      ),
    );
  }
}