Chat in a group channel

In a group channel, you can have both 1-to-1 chat and 1-to-N chats through the SBUGroupChannelViewController class. There are two types of group channel based on whether a user needs an invitation to join: private and public. UIKit also provides a Supergroup channel to facilitate a more stable chat environment for a larger number of users.

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UIKit supports plain text messages, file messages, and media content such as photos and videos to be sent in group channels. Once delivered, those messages are grouped by time in minutes and date in the channel. If the permission to access photo library is limited when sending a file message containing photos and videos, the SBUSelectablePhotoViewController class is used.

To learn more about the channels, go to the Channel types page in Chat SDK.

Refer to the table below to see what features there are in SBUGroupChannelViewController.

You can start building a channel-based chat service by calling the SBUGroupChannelViewController class. It uses SBUAdminMessageCell, SBUUserMessageCell, and SBUFileMessageCell classes to display the messages in the channel. It's also in charge of auto connecting to Sendbird server and internal functions to handle core features of UIKit such as pagination and real-time updates.

Note: You can initialize SBUGroupChannelViewController by setting the value of ChannelURL or GroupChannel. If you've already created MessageListParams, we recommend you to set all of the objects together. Otherwise, the default values are used for these classes.

You can start building a chat in group channel view through the SBUGroupChannelViewController class. Use either the init(channelURL:messageListParams:) or init(channel:messageListParams:)) initializer to create the instance and display the view.

let channelVC = SBUGroupChannelViewController(
    channelURL: {CHANNEL_URL},
    messageListParams: messageListParams
)
let navigationController = UINavigationController(rootViewController: channelVC)
present(navigationController, animated: true)

The following items are key elements of SBUGroupChannelViewController that are used to create a functional chat in group channel view.

In the SBUGroupChannelViewController class, SBUGroupChannelModule and its components are used to create and display the group channel view. The module is composed of three components: HeaderComponent,ListComponent, and InputComponent.

When the loadView() method of the view controller is called, the module components get added to the view in the setupView() method of the Sendbird UIKit's view life cycle. Then, the configure method of each module component is called to set the property values and display the view.

The HeaderComponent includes a channel title, a back button that takes the user to the previous view, and a button that takes the user to the channel settings view. Each property corresponds to the elements in the navigation bar of the view controller.

The following table shows the parameters of the configure method of the HeaderComponent.

Note: To learn more about the delegate and the properties of the HeaderComponent for group channels, go to the API reference page.

The ListComponent shows a list of all the messages in the group channel. The following table shows the parameters of the configure method of the ListComponent.

Note: To learn more about the delegate, data source, and the properties of the ListComponent for group channels, go to the API reference page.

The InputComponent shows the input field of a channel where users can type and send their messages. The following table shows the parameters of the configure method of the InputComponent.

Note: To learn more about the delegate, data source, and the properties of the InputComponent for group channels, go to the API reference page.

The SBUGroupChannelViewController class uses a view model that is a type of the SBUGroupChannelViewModel class. The view model is created in the initializer of the view controller through the createViewModel(channel:channelURL:messageListParams:startingPoint:showIndicator:) method. When the view model object is created, it retrieves message list data from Chat SDK to the view controller and updates the view through the baseChannelViewModel(_:didReceiveNewMessage:forChannel:) event.

Note: If the value of channel or channelURL is invalid, the view model cannot retrieve the message list.

The following table shows the parameters of the createViewModel method.

In the SBUGroupChannelViewModel message list, known as fullMessageList, messages are organized based on their sending status and their arrival time.

In this layout, older messages are positioned at the top of the list, while the most recent messages appear at the bottom. As new messages are successfully sent and received, they are displayed at the lower end of the list, just above any messages that are pending or have failed. Below these, you'll find any messages that are still pending or have failed to send. These are ordered based on their original sending time. Furthermore, if the bubble typing indicator feature is enabled for your channel, this indicator will be consistently shown at the very bottom of the message list, regardless of the statuses of other messages. This layout prioritizes the visibility of new, successful messages while maintaining awareness of pending and failed messages, as well as ongoing typing activity.

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Note: To learn more about the methods and the event delegates of the view model, go to this API reference page.

The SBUBaseChannelViewController class provides properties and methods that are used in both group channels and open channels. To learn more about these properties, go to the API reference page.

You can customize the chat UI of a group channel by making changes to the following parts:

• Message cell
• View controller
• Module component
• View model

You can customize the message cells by inheriting different message cells as shown in the list below. Each of the following message cell inherits SBUContentBaseMessageCell.

• SBUUserMessageCell
• SBUFileMessageCell
• SBUMultipleFilesMessageCell
• SBUAdminMessageCell
• SBUTypingIndicatorMessageCell

To customize the message cells listed above, you can override each message class. You can selectively override the components, methods, or add custom views into the existing view hierarchy.

The below is an image of the view hierarchy of SBUContentBaseMessageCell.

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The code below shows an example of adding a UILabel view into SBUUserMessageCell.

class MyUserMessageCell: SBUUserMessageCell {
    // The custom view to be added to SBUUserMessageCell
    lazy var myLabel: UILabel = {
        let label = UILabel()
        label.textColor = .systemBlue
        label.font = .systemFont(ofSize: 14)
        label.numberOfLines = 0
        return label
    }()
    
    override func setupViews() {
        super.setupViews()
        
        // Insert myLabel view inside mainContainerView of SBUUserMessageCell.
        self.mainContainerView.addArrangedSubview(myLabel)
    }
    
    override func configure(with configuration: SBUBaseMessageCellParams) {
        super.configure(with: configuration)
        
        guard let configuration = configuration as? SBUUserMessageCellParams else { return }
        guard let userMessage = configuration.userMessage else { return }
        
        myLabel.text = {YOUR_DATA}
    }
}

// Set up your custom `GroupChannelViewController` in `SBUViewControllerSet` before using it. 
class CustomViewController: SBUGroupChannelViewController {
    override func setupViews() {
        // Register the custom message cell.
        self.listComponent?.register(userMessageCell: MyUserMessageCell())
        super.setupViews()
    }
}

SBUViewControllerSet.GroupChannelViewController = CustomViewController.self

There are two ways to customize the view controller: change the default view controller value in the global SBUViewControllerSet class or set a single-use custom view controller in the key function.

The custom view controller in the code below is used in the following customization examples.

class CustomGroupChannelViewController: SBUGroupChannelViewController {
    // Implement custom code here.
}

1. Change the value of SBUViewControllerSet.GroupChannelViewController.

SBUViewControllerSet.GroupChannelViewController = CustomGroupChannelViewController.self

// The view controller will now use `CustomGroupChannelViewController` as the default value.

2. Use a one-time custom view controller in the chat in group channel view.

let channelVC = CustomGroupChannelViewController(channelURL: {CHANNEL_URL})
let navigationController = UINavigationController(rootViewController: channelVC)
present(navigationController, animated: true)

There are two ways to customize a module component: change the default component value in the global SBUModuleSet.GroupChannelModule class or set a single-use custom module component in the view controller. If there is no set custom value in the loadView() method of SBUGroupChannelViewController, the module components will use the default values.

The custom header component in the code below is used in the following customization examples.

class CustomHeader: SBUGroupChannelModule.Header {
    // Implement custom code here.
}

1. Change the value of SBUModuleSet.GroupChannelModule.HeaderComponent.

SBUModuleSet.GroupChannelModule.HeaderComponent = CustomHeader.self

let channelVC = SBUViewControllerSet.GroupChannelViewController(channelURL: {CHANNEL_URL})

// The `headerComponent` in `SBUGroupChannelViewController` will now use `customHeader` as the default value.

2. Change the module component in SBUGroupChannelViewController.

let channelVC = SBUViewControllerSet.GroupChannelViewController(channelURL: {CHANNEL_URL})
channelVC.headerComponent = CustomHeader()

Note: To learn more about the methods of SBUGroupChannelModule, go to the API reference page.

In order to use a customized view model or customize the existing view model's event delegate, you must override the view controller.

1. Use a customized View model.

class CustomChannelViewController: SBUGroupChannelViewController {
    override func func createViewModel(
        channel: BaseChannel? = nil,
        channelURL: String? = nil,
        messageListParams: MessageListParams? = nil,
        startingPoint: Int64? = LLONG_MAX,
        showIndicator: Bool = true
    ) {
        // Set `viewModel` to the `CustomViewModel` object.
        self.viewModel = CustomViewModel()
        // Implement your code here.
    }
}

2. Customize the view model's event delegate.

extension CustomChannelViewController: SBUGroupChannelViewModelDelegate {
    override func baseChannelViewModel(
        _ viewModel: SBUBaseChannelViewModel,
        didChangeChannel channel: BaseChannel?,
        withContext context: MessageContext
    ) {
        // Implement your code here.
}