ChannelsScreen

The easiest way to set up a screen that shows the active user’s channels and gives them the ability to search for a specific channel is to use the ChannelsScreen.

ChannelsScreen sets up the following functionality internally:

• Header with the information of the current user and customizable title and action.
• Search input that can be shown or hidden that allows users to search for channels by name.
• List of user’s channels with pagination, based on defined filters and sorting.
• Menu with detailed channel information, shown when long clicking on a Channel in the list.

It also sets up all the business logic and styles the UI according to our default design system.

Let’s see how to integrate the component.

Usage

To use ChannelsScreen, you just need to call it within setContent() in your Activity or Fragment:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    setContent {
        ChatTheme {
            ChannelsScreen()
        }
    }
}

This small snippet will produce a fully working solution, as shown in the image below.

To get a better feel of the component, you’ll want to customize its actions.

Handling Actions

When it comes to action handlers exposed in the ChannelsScreen signature you have access to the following:

fun ChannelsScreen(
    ..., // Filters and UI customization
    onHeaderActionClick: () -> Unit = {},
    onHeaderAvatarClick: () -> Unit = {},
    onItemClick: (Channel) -> Unit = {},
    onViewChannelInfoAction: (Channel) -> Unit = {},
    onBackPressed: () -> Unit = {},
)

There are four main action handlers you can use with the ChannelsScreen:

• onHeaderActionClick: Handler for the default header trailing icon click action.
• onHeaderAvatarClick: Handler for the clicks on the user avatar in the header.
• onItemClick: Handler for a Channel being clicked.
• onViewChannelInfoAction: Handler for the View info action selected in SelectedChannelMenu.
• onBackPressed: Handler for the system back button being clicked.

All of these actions are empty by default, but if you want to customize them, you can do the following:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    setContent {
        ChatTheme {
            ChannelsScreen(
                onItemClick = {
                    // Open messages screen
                },
                onHeaderActionClick = {
                    // Handle the header click action
                },
                onHeaderAvatarClick = {
                    // Handle the header avatar clicks
                },
                onViewChannelInfoAction = {
                    // Show UI to view more channel info
                },
                onBackPressed = { finish() },
            )
        }
    }
}

Customization

ChannelsScreen is one of our screen components and as such it doesn’t offer much customization. As with any component, you can customize the content theme and styling by wrapping it the ChatTheme.

When it comes to UI and behavior customization in the ChannelsScreen signature you have access to the following:

fun ChannelsScreen(
    filters: FilterObject? = null,
    querySort: QuerySort<Channel> = QuerySort.desc("last_updated"),
    title: String = "Stream Chat",
    isShowingHeader: Boolean = true,
    isShowingSearch: Boolean = true,
    channelLimit: Int = ChannelListViewModel.DEFAULT_CHANNEL_LIMIT,
    memberLimit: Int = ChannelListViewModel.DEFAULT_MEMBER_LIMIT,
    messageLimit: Int = ChannelListViewModel.DEFAULT_MESSAGE_LIMIT,
    ... // Action handlers
)

• filters: These filters are applied to the channel query, meaning you can customize what data to show in the list. By default they are null which signals us to use default messaging channel filters.
• querySort: Like with filters, these are applied to the list data and affect its sorting order.
• title: The title of the ChannelListHeader.
• isShowingHeader: Flag that affects if we show the ChannelListHeader. true by default.
• isShowingSearch: Flag that affects if we show the SearchInput. false by default.
• channelLimit The limit of channels queried per page.
• memberLimit The limit of members requested per channel.
• messageLimit The limit of messages requested per channel item.