ChannelListView

A Widget For Displaying A List Of Channels

Find the pub.dev documentation here

Background

Channels are fundamental elements of Stream Chat and constitute shared spaces which allow users to message each other.

1:1 conversations and groups are both examples of channels, albeit with some (distinct/non-distinct) differences. Displaying the list of channels that a user is a part of is a pattern present in most messaging apps.

The ChannelListView widget allows displaying a list of channels to a user. By default, this is NOT ONLY the channels that the user is a part of. This section goes into setting up and using a ChannelListView widget.

Basic Example

Here is a basic example of the ChannelListView widget. It consists of the main widget itself, a Filter to filter only the channels that the user is a part of, sorting by last message time, pagination parameters, and the widget to use when a particular channel is clicked.

class ChannelListPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ChannelsBloc(
        child: ChannelListView(
          filter: Filter.in_('members', [StreamChat.of(context).user.id]),
          sort: [SortOption('last_message_at')],
          pagination: PaginationParams(
            limit: 20,
          ),
          channelWidget: ChannelPage(),
        ),
      ),
    );
  }
}

This example by default displays the channels that a user is a part of. Now let's look at customizing the widget.

Customizing the Channel Preview

A common aspect of the widget needed to be tweaked according to each app is the Channel Preview (the Channel tile in the list). To do this, we use the channelPreviewBuilder parameter like this:

ChannelListView(
  ...
  channelPreviewBuilder: (context, channel) {
    return ListTile(
      tileColor: Colors.amberAccent,
      title: Center(
        child: ChannelName(),
      ),
    );
  },
),

Which gives you a new Channel preview in the list:

Adding Swipe Actions

To add actions (such as delete, more info, etc) when Channel preview is swiped left, set the swipeToAction parameter to true.

ChannelListView(
  ...
  swipeToAction: true,
),

This adds two basic actions - info and delete:

To add custom actions of your own, use the swipeActions parameter:

ChannelListView(
  ...
  swipeToAction: true,
  swipeActions: [
    SwipeAction(
        color: Colors.blue,
        iconWidget: Icon(Icons.add),
        onTap: (channel) {
            // Things to do on icon tap
        },
    ),
    // Other actions here
  ]
),