ChannelListCore

A Widget For Building A List Of Channels

Background

The UI SDK of Stream Chat supplies a ChannelListView class that builds a list of channels fetching according to the filters and sort order given. However, in some cases, implementing novel UI is necessary that cannot be done using the customization approaches given in the widget.

To do this, we extracted the logic required for fetching channels into a 'Core' widget - a widget that fetches channels in the expected way via the usual parameters but does not supply any UI and instead exposes builders to build the UI in situations such as loading, empty data, errors, and on data received.

Basic Example

ChannelListCore is a simplified class that allows fetching a list of channels while exposing UI builders.

This allows you to construct your own UI while not having to worry about the specific logic of fetching channels in your app.

A ChannelListController is used to reload and paginate data.

class ChannelListPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ChannelListCore(
        filter: Filter.in_(
            'members',
            [StreamChat.of(context).user!.id],
        ),
        sort: [SortOption('last_message_at')],
        pagination: PaginationParams(
          limit: 20,
        ),
        errorBuilder: (context, err) {
          return Center(
            child: Text('An error has occured'),
          );
        },
        emptyBuilder: (context) {
          return Center(
            child: Text('Nothing here...'),
          );
        },
        loadingBuilder: (context) {
          return Center(
            child: CircularProgressIndicator(),
          );
        },
        listBuilder: (context, list) {
          return ChannelPage(list);
        }
      ),
    );
  }
}

Make sure to have a StreamChatCore ancestor in order to provide the information about the channels.