This guide walks you through creating a tab-based messaging interface in your iOS application using CometChat UI Kit for iOS. The UI includes tabs for Chats, Calls, Users, and Groups, offering an organized and fluid experience.

​
User Interface Preview

This layout contains:
  1. Conversations – Lists all recent chats.
  2. Calls – Displays call logs.
  3. Users – Lists available users.
  4. Groups – Lists available groups.

​
Step-by-Step Guide

​
Step 1: Initialize UIKit in SceneDelegate.swift

Ensure UIKit is initialized and the user is logged in before presenting the tabbed view.
SceneDelegate.swift
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    guard let windowScene = (scene as? UIWindowScene) else { return }

    let uikitSettings = UIKitSettings()
        .set(appID: "<#Enter Your App ID Here#>")
        .set(region: "<#Enter Your Region Code Here#>")
        .set(authKey: "<#Enter Your AuthKey Here#>")
        .subscribePresenceForAllUsers()
        .build()

    CometChatUIKit.init(uiKitSettings: uikitSettings) { result in
        switch result {
        case .success:
            CometChatUIKit.login(uid: "cometchat-uid-1") { loginResult in
                switch loginResult {
                case .success:
                    DispatchQueue.main.async {
                        self.setupTabbedView(windowScene: windowScene)
                    }
                default:
                    break
                }
            }
        default:
            break
        }
    }
}

​
Step 2: Setup Tab Bar

Create a method to display the tab layout.
SceneDelegate.swift
func setupTabbedView(windowScene: UIWindowScene) {

    // Create the main Tab Bar Controller
    let tabBarController = UITabBarController()
    tabBarController.tabBar.backgroundColor = .white
    
    // MARK: - Conversations Tab
    let conversationsVC = CometChatConversations()
    let conversationsNav = UINavigationController(rootViewController: conversationsVC)
    conversationsVC.tabBarItem = UITabBarItem(
        title: "CHATS",
        image: UIImage(systemName: "message.fill"),
        tag: 0
    )
    
    // Handle item click inside conversation list
    conversationsVC.set(onItemClick: { [weak conversationsNav] conversation, indexPath in
        let messagesVC = MessagesVC()
        messagesVC.group = conversation.conversationWith as? Group
        messagesVC.user = conversation.conversationWith as? CometChatSDK.User
        messagesVC.hidesBottomBarWhenPushed = true
        conversationsNav?.pushViewController(messagesVC, animated: true)
    })
    
    // MARK: - Call Logs Tab
    let callLogsVC = CometChatCallLogs()
    let callLogsNav = UINavigationController(rootViewController: callLogsVC)
    callLogsVC.tabBarItem = UITabBarItem(
        title: "CALLS",
        image: UIImage(systemName: "phone.fill"),
        tag: 1
    )
    
    // MARK: - Users Tab
    let usersVC = CometChatUsers()
    let usersNav = UINavigationController(rootViewController: usersVC)
    usersVC.tabBarItem = UITabBarItem(
        title: "USERS",
        image: UIImage(systemName: "person.2.fill"),
        tag: 2
    )
    
    // MARK: - Groups Tab
    let groupsVC = CometChatGroups()
    let groupsNav = UINavigationController(rootViewController: groupsVC)
    groupsVC.tabBarItem = UITabBarItem(
        title: "GROUPS",
        image: UIImage(systemName: "person.3.fill"),
        tag: 3
    )
    
    // Assign all navigation controllers to the Tab Bar
    tabBarController.viewControllers = [
        conversationsNav,
        callLogsNav,
        usersNav,
        groupsNav
    ]
    
    // Ensures layout includes space for opaque bars like the navigation bar
    tabBarController.extendedLayoutIncludesOpaqueBars = true
    
    // Setup and display main window with tabBarController as root
    window = UIWindow(windowScene: windowScene)
    window?.rootViewController = tabBarController
    window?.makeKeyAndVisible()

}

​
Step 3: Create MessagesVC.swift

This view controller handles chat between users or within groups.
MessagesVC.swift
import UIKit
import CometChatSDK
import CometChatUIKitSwift

/// A view controller that displays a chat interface using CometChat components
class MessagesVC: UIViewController {
    
    // MARK: - Properties
    
    /// The user entity for one-on-one chats
    var user: User?
    
    /// The group entity for group chats
    var group: Group?
    
    // MARK: - UI Components
    
    /// Header view displaying user/group information
    private lazy var headerView: CometChatMessageHeader = {
        let view = CometChatMessageHeader()
        view.translatesAutoresizingMaskIntoConstraints = false
        // Configure for the appropriate conversation type
        if let user = user {
            view.set(user: user)
        } else if let group = group {
            view.set(group: group)
        }
        view.set(controller: self)
        return view
    }()
    
    /// Message input composer view
    private lazy var composerView: CometChatMessageComposer = {
        let composer = CometChatMessageComposer()
        composer.translatesAutoresizingMaskIntoConstraints = false
        // Configure for the appropriate conversation type
        if let user = user {
            composer.set(user: user)
        } else if let group = group {
            composer.set(group: group)
        }
        composer.set(controller: self)
        return composer
    }()
    
    /// List view displaying chat messages
    private lazy var messageListView: CometChatMessageList = {
        let listView = CometChatMessageList()
        listView.translatesAutoresizingMaskIntoConstraints = false
        // Configure for the appropriate conversation type
        if let user = user {
            listView.set(user: user)
        } else if let group = group {
            listView.set(group: group)
        }
        listView.set(controller: self)
        return listView
    }()
    
    // MARK: - Lifecycle Methods
    
    override func viewDidLoad() {
        super.viewDidLoad()
        configureView()
        setupLayout()
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        navigationController?.setNavigationBarHidden(false, animated: true)
    }
    
    // MARK: - Private Methods
    
    /// Configure basic view properties
    private func configureView() {
        view.backgroundColor = .systemBackground
        navigationController?.setNavigationBarHidden(true, animated: false)
    }
    
    /// Set up view hierarchy and constraints
    private func setupLayout() {
        // Add subviews to the view hierarchy
        [headerView, messageListView, composerView].forEach { view.addSubview($0) }
        
        // Set up constraints
        NSLayoutConstraint.activate([
            // Header view constraints
            headerView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            headerView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            headerView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            headerView.heightAnchor.constraint(equalToConstant: 50),
            
            // Message list view constraints
            messageListView.topAnchor.constraint(equalTo: headerView.bottomAnchor),
            messageListView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            messageListView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            messageListView.bottomAnchor.constraint(equalTo: composerView.topAnchor),
            
            // Composer view constraints
            composerView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            composerView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            composerView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)
        ])
    }
}

​
Next Steps

​
Enhance the User Experience