ViewModel & Data - CometChat Docs

Each component’s ViewModel manages data fetching, state transitions, and business logic via LiveData. You can access it to configure request parameters, observe state changes, or manipulate the data list directly.

Accessing the ViewModel

Kotlin
Java

val conversations = CometChatConversations(context)
val viewModel: ConversationsViewModel = conversations.getViewModel()

CometChatConversations conversations = new CometChatConversations(context);
ConversationsViewModel viewModel = conversations.getViewModel();

Configuring Data Fetching with RequestBuilders

Use setConversationsRequestBuilder to control what data the component fetches. The builder accepts SDK parameters like limits, tags, and filters.

Kotlin
Java

// Filter conversations by tags and limit to 20 results
val builder = ConversationsRequest.ConversationsRequestBuilder()
    .setLimit(20)
    .setTags(listOf("important", "pinned"))
    .withTags(true)

conversations.setConversationsRequestBuilder(builder)

// Filter conversations by tags and limit to 20 results
ConversationsRequest.ConversationsRequestBuilder builder =
    new ConversationsRequest.ConversationsRequestBuilder()
        .setLimit(20)
        .setTags(Arrays.asList("important", "pinned"))
        .withTags(true);

conversations.setConversationsRequestBuilder(builder);

Pass the builder object, not the result of .build(). The component calls .build() internally.

LiveData Observables

The ViewModel exposes LiveData observables you can observe for custom logic:

Observable	Type	Description
`getMutableConversationList()`	`MutableLiveData<List<Conversation>>`	The current list of conversations
`getStates()`	`MutableLiveData<UIKitConstants.States>`	Component state (LOADING, LOADED, EMPTY, ERROR)
`insertAtTop()`	`MutableLiveData<Integer>`	Emits the index when a new conversation is inserted at the top
`moveToTop()`	`MutableLiveData<Integer>`	Emits the index when a conversation moves to the top
`updateConversation()`	`MutableLiveData<Integer>`	Emits the index when a conversation is updated
`remove()`	`MutableLiveData<Integer>`	Emits the index when a conversation is removed
`progressState()`	`MutableLiveData<UIKitConstants.DeleteState>`	Tracks delete operation progress
`playSound()`	`MutableLiveData<Boolean>`	Triggers when a new message sound should play
`getCometChatException()`	`MutableLiveData<CometChatException>`	Emits errors from the SDK

Kotlin
Java

val viewModel = conversations.getViewModel()

// Observe state changes
viewModel.getStates().observe(lifecycleOwner) { state ->
    when (state) {
        UIKitConstants.States.LOADING -> { /* show custom loading */ }
        UIKitConstants.States.LOADED -> { /* data ready */ }
        UIKitConstants.States.EMPTY -> { /* no conversations */ }
        UIKitConstants.States.ERROR -> { /* handle error */ }
    }
}

// Observe the conversation list
viewModel.getMutableConversationList().observe(lifecycleOwner) { list ->
    // React to list changes
}

ConversationsViewModel viewModel = conversations.getViewModel();

// Observe state changes
viewModel.getStates().observe(lifecycleOwner, state -> {
    if (state == UIKitConstants.States.LOADING) {
        // show custom loading
    } else if (state == UIKitConstants.States.LOADED) {
        // data ready
    }
});

// Observe the conversation list
viewModel.getMutableConversationList().observe(lifecycleOwner, list -> {
    // React to list changes
});

Mutation Methods

The ViewModel provides methods to programmatically manipulate the data list:

Method	Description
`addList(List<Conversation>)`	Append a list of conversations
`remove(Conversation)`	Remove a specific conversation
`remove(int index)`	Remove a conversation by index
`update(Conversation, boolean)`	Update a conversation in the list
`refreshList()`	Clear and re-fetch from the server
`clear()`	Clear all conversations from the list
`fetchConversation()`	Fetch the next page of conversations
`deleteConversation(Conversation)`	Delete a conversation via the SDK

Kotlin
Java

val viewModel = conversations.getViewModel()

// Refresh the entire list
viewModel.refreshList()

// Remove a specific conversation
viewModel.remove(conversation)

// Clear all data
viewModel.clear()

ConversationsViewModel viewModel = conversations.getViewModel();

// Refresh the entire list
viewModel.refreshList();

// Remove a specific conversation
viewModel.remove(conversation);

// Clear all data
viewModel.clear();

Lifecycle Callbacks

Intercept data loading lifecycle events with these callbacks on the View:

Callback	Triggered When
`setOnLoad(OnLoad<Conversation>)`	Data has been successfully loaded
`setOnEmpty(OnEmpty)`	The data list is empty after loading

Kotlin
Java

conversations.setOnLoad { list ->
    // Called when conversations are loaded
    Log.d("Conversations", "Loaded ${list.size} conversations")
}

conversations.setOnEmpty {
    // Called when no conversations exist
    Log.d("Conversations", "No conversations found")
}

conversations.setOnLoad(list -> {
    // Called when conversations are loaded
    Log.d("Conversations", "Loaded " + list.size() + " conversations");
});

conversations.setOnEmpty(() -> {
    // Called when no conversations exist
    Log.d("Conversations", "No conversations found");
});

Adapter Customization — Manipulate list data at the adapter level.
Customization Overview — See all customization categories.

​Accessing the ViewModel

​Configuring Data Fetching with RequestBuilders

​LiveData Observables

​Mutation Methods

​Lifecycle Callbacks

​Related

Accessing the ViewModel

Configuring Data Fetching with RequestBuilders

LiveData Observables

Mutation Methods

Lifecycle Callbacks

Related