GroupedChannels Sample (Android)

Setup

Snapshot version: 6.37.3-202604241416-SNAPSHOT

To register the snapshot repository in your project, add the following line to the repositories block of your settings.gradle.kts:

maven { url = uri("https://central.sonatype.com/repository/maven-snapshots/") }

Then, to include the Stream Chat in you project, add the following lines to you app build.gradle dependencies block (or via the libs.versions.toml catalog):

implementation("io.getstream:stream-chat-android-compose:6.37.3-202604241416-SNAPSHOT")
implementation("io.getstream:stream-chat-android-offline:6.37.3-202604241416-SNAPSHOT")

QueryGroupedChannels operation

The QueryGroupedChannels operation is defined on the ChatClient :

@CheckResult
public fun queryGroupedChannels(
    limit: Int? = null,
    watch: Boolean = false,
    presence: Boolean = false,
): Call<GroupedChannels>

ChannelViewModelFactory setup

After a successful connection to the Stream service, calling the queryGroupedChannels method will return a result holding the first page of each group (all, new, current, expired). You can then use these groups to prefill the ChannelListViewModel with the initial data, skipping the 4 separate QueryChannels invokations. To do that, you need the following setup:

// Create the ChannelViewModelFactory (one per group)
private val allFactory by lazy {
    ChannelViewModelFactory(
        chatClient = ChatClient.instance(),
        querySort = QuerySortByField.descByName("last_message_at"),
        filters = allFilter(),
        channelLimit = 20,
        chatEventHandlerFactory = GroupedChatEventHandlerFactory("all") { channel ->
            // accept all channels the user is member of
            true
        },
        // Prevent initial data fetch
        skipInitialQuery = true,
    )
}

// Fetch the initial data
ChatClient.instance().queryGroupedChannels(watch = true).enqueue(
  onSuccess = { result ->
    // retrieve data for "all" group
    val allData = result.groups["all"]
    // pre-fill the VM with "all" data
    allViewModel.prefill(allData)

    // pre-fill other groups ("current", "new", ""expired)
    // ...
  }
)

The important steps are:

• ChannelViewModelFactory(skipInitialQuery = true) - skips the initial load for the VM data
• ChannelListViewModel.prefill(group) - populates the VM with the data fetched from the GroupedChannels

Unread counts per group

To observe the live updates to the unread counts per group, you can observe the following flow:

ChatClient.instance()
    .globalStateFlow
    .flatMapLatest { it.groupedUnreadChannels }

The groupedUnreadChannels is a Map keyed by the group name (all, new...), with values equal to the current unread count of the group.

Event matching

To ensure channels switch to their appropriate group after receiving/sending a message, you would also need to implement custom ChatEventHandler -> which will cross-check each channel against the expected filters - telling the ChannelList whether the channel should be added/removed from its current state. The ChatEventHandler is then passed to the ChannelViewModelFactory constructor.

An example of such ChatEventHandler can be found here.