CometChat Flutter UIKit v5 — Customization

Four tiers of customization, from simple to deep.

Tier 1: Props

Pass props directly to components:

CometChatMessageList(
  user: user,
  hideEditMessageOption: true,
  hideReactionOption: true,
  receiptsVisibility: false,
)

Tier 2: Slot Views

Replace specific UI sections via callback props:

CometChatConversations(
  subtitleView: (context, conversation) {
    final lastMessage = conversation.lastMessage;
    if (lastMessage is TextMessage) {
      return Text(lastMessage.text, maxLines: 1, overflow: TextOverflow.ellipsis);
    }
    return null; // Falls back to default
  },
  trailingView: (conversation) {
    return Badge(count: conversation.unreadMessageCount);
  },
)

CometChatMessageHeader(
  listItemView: (group, user, context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text("Thread", style: TextStyle(fontWeight: FontWeight.bold)),
        Text(user?.name ?? group?.name ?? ""),
      ],
    );
  },
)

Available slot views per component:

• CometChatConversations: subtitleView, listItemView, trailingView, leadingView, titleView
• CometChatMessageHeader: subtitleView, listItemView, trailingView
• CometChatMessageList: headerView, footerView, loadingStateView, emptyStateView, errorStateView
• CometChatUsers: subtitleView, listItemView, leadingView, titleView, trailingView
• CometChatGroups: subtitleView, listItemView, leadingView, titleView, trailingView

Tier 3: Text Formatters

Custom text formatters transform how message text is displayed:

CometChatMessageList(
  textFormatters: [
    CometChatEmailFormatter(),
    CometChatPhoneNumberFormatter(),
    CometChatUrlFormatter(),
    CometChatMentionsFormatter(
      user: user,
      group: group,
      onMentionTap: (mention, mentionedUser, {message}) {
        // Navigate to user's chat
      },
    ),
  ],
)

Built-in formatters:

• CometChatEmailFormatter — makes emails tappable
• CometChatPhoneNumberFormatter — makes phone numbers tappable
• CometChatUrlFormatter — makes URLs tappable
• CometChatMentionsFormatter — handles @mentions with tap callbacks

Pass the same formatters to both CometChatMessageList and CometChatMessageComposer for consistency.

Tier 4: DataSource Decorator Pattern

The deepest customization level. ChatConfigurator uses a decorator pattern with MessagesDataSource as the base:

ChatConfigurator
  └── DataSource (interface)
      └── MessagesDataSource (default implementation)
          └── ExtensionDecorator (wraps and overrides)

How extensions use it

Each extension (polls, stickers, link preview, etc.) has a decorator:

// Example: PollsExtensionDecorator wraps the DataSource
class PollsExtensionDecorator extends DataSourceDecorator {
  PollsExtensionDecorator(DataSource dataSource) : super(dataSource);

  @override
  List<CometChatMessageTemplate> getAllMessageTemplates() {
    // Add poll template to existing templates
    return [...super.getAllMessageTemplates(), _getPollTemplate()];
  }
}

Extensions are registered via UIKitSettingsBuilder:

final settings = (UIKitSettingsBuilder()
  ..extensions = CometChatUIKitChatExtensions.getDefaultExtensions()
  ..aiFeature = CometChatUIKitChatAIFeatures.getDefaultAiFeatures()
).build();

Available extensions

Extension	Decorator	What it adds
Polls	PollsExtensionDecorator	Poll creation + voting bubble
Stickers	StickersExtensionDecorator	Sticker keyboard + bubble
Link Preview	LinkPreviewExtensionDecorator	URL preview cards
Message Translation	MessageTranslationExtensionDecorator	Translate option
Image Moderation	ImageModerationExtensionDecorator	NSFW filter
Collaborative Document	CollaborativeDocumentExtensionDecorator	Shared doc
Collaborative Whiteboard	CollaborativeWhiteboardExtensionDecorator	Shared whiteboard
Thumbnail Generation	ThumbnailGenerationExtensionDecorator	Image thumbnails

CometChatCallingExtension

The calling extension also uses this pattern:

class CometChatCallingExtension extends ExtensionsDataSource {
  @override
  void addExtension() {
    ChatConfigurator.enable((dataSource) =>
        CallingExtensionDecorator(dataSource, configuration: configuration));
  }
}

Message Templates

CometChatMessageTemplate defines how a message type is rendered:

CometChatMessageList(
  templates: [
    CometChatMessageTemplate(
      type: 'custom_type',
      category: 'custom',
      contentView: (message, context, alignment) {
        return Container(
          child: Text('Custom bubble: ${message.id}'),
        );
      },
    ),
  ],
)

Options Menu Customization

Add or replace long-press options on conversations, users, groups:

CometChatConversations(
  // Replace all options
  setOptions: (conversation, controller, context) {
    return [CometChatOption(id: 'pin', title: 'Pin', onClick: () { ... })];
  },
  // Add to existing options
  addOptions: (conversation, controller, context) {
    return [CometChatOption(id: 'archive', title: 'Archive', onClick: () { ... })];
  },
)

Header Options (Messages)

CometChatMessageHeader(
  options: (user, group, context) {
    return [
      CometChatOption(
        id: 'user-info',
        title: 'User Info',
        iconWidget: Icon(Icons.info_outline),
        onClick: () { ... },
      ),
      CometChatOption(
        id: 'search',
        title: 'Search',
        iconWidget: Icon(Icons.search),
        onClick: () { ... },
      ),
    ];
  },
)

Checklist — Customization

• Start with props (Tier 1) before going deeper
• Slot views return null to fall back to default rendering
• Text formatters consistent between MessageList and Composer
• Extensions registered via UIKitSettingsBuilder.extensions
• Custom templates specify type and category