Invite users

In UIKit for iOS, you can invite users to a group channel through the SBUInviteUserViewController class. The view controller uses the SBUUserCell class to display a list of users who aren't in the channel and invite them. Unless you have a specific list of users you selected, all users who are using your chat service is displayed in the user list by default.

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Note: If you set the starting point of your chat service to be the channel list, group or open channel, channel settings or member list, you can seamlessly guide your users to the invite users view.

You can start building an invite users view through the SBUInviteUserViewController class. Use either the init(channelURL:users:) or init(channel:users:) initializer to create the instance and display the view as shown below.

// Case 1: Use `channelURL`.
let inviteVC = SBUInviteUserViewController(
    channelURL: {CHANNEL_URL},
    users: [{MEMBER}]
)
let navigationController = UINavigationController(rootViewController: inviteVC)
present(navigationController, animated: true)

// Case 2: Use `channel` object.
let inviteVC = SBUInviteUserViewController(
    channel: {CHANNEL},
    users: [{MEMBER}]
)
let navigationController = UINavigationController(rootViewController: inviteVC)
present(navigationController, animated: true)

Note: If you don't set a value to the user parameter, the default value of nil is used instead.

The following items are key elements of SBUInviteUserViewController that are used to create a functional view.

In the SBUInviteUserViewController class, SBUInviteUserModule and its components are used to create and display the invite users view. The module is composed of two components: HeaderComponent and ListComponent.

Each module component is assigned a value from the SBUModuleSet class and gets 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 text button that invites the selected users to the channel.

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

Note: To learn more about the delegate, data source, and the properties of the HeaderComponent, go to this API reference page.

The ListComponent shows a list of all users that can be invited. If the user is already a channel member, they will not be shown on the list.

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, go to this API reference page.

The SBUInviteUserViewController class uses a view model that is a type of the SBUInviteUserViewModel class. The view model is created in the initializer of the view controller through the createViewModel(channel:channelURL:channelType:users:) method. When the view model object is created, it retrieves channel list data from Chat SDK to the view controller and updates the view through the baseSelectedUserViewModel(_:didChangeUserList:needsToReload:) event.

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

The following table shows the parameters of the createViewModel method.

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

For detailed information about the properties of SBUInviteUserViewController, go to this API reference page.

You can customize the invite users view by changing the view controller, module component, and view model that correspond to this key function.

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 CustomInviteUserViewController: SBUInviteUserViewController {
    // Implement custom code here.

1. Change the value of SBUViewControllerSet.InviteUserViewController.

SBUViewControllerSet.InviteUserViewController = CustomInviteUserViewController.self

// All ViewController in invite users view will now use `CustomInviteUserViewController` as the default value.

2. Use a one-time custom view controller in the invite users view.

let inviteVC = CustomInviteUserViewController(
    channel: {CHANNEL},
    users: [{MEMBER}]
)
let navigationController = UINavigationController(rootViewController: inviteVC)
present(navigationController, animated: true)

There are two ways to customize a module component: change the default module component type in the global SBUModuleSet.InviteUserModule class or set a single-use custom module component in the view controller.

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

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

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

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

SBUModuleSet.InviteUserModule.HeaderComponent = CustomHeader.self

let inviteVC = SBUViewControllerSet.InviteUserViewController(
    channel: {CHANNEL},
    users: [{MEMBER}]
)

2. Change the module component in SBUInviteUserViewController.

let inviteVC = SBUViewControllerSet.InviteUserViewController(
    channel: {CHANNEL},
    users: [{MEMBER}]
)
channelSettingsVC.headerComponent = CustomHeader()

Note: To learn more about the methods of SBUInviteUserModule, go to this 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 CustomViewController: SBUInviteUserViewController {
    override func createViewModel(channel: BaseChannel? = nil,
                                  channelURL: String? = nil,
                                  channelType: ChannelType = .group,
                                  users: [SBUUser]? = nil) {
        // Set `viewModel` to the `CustomViewModel` object.
        self.viewModel = CustomViewModel()

        // Implement your code here.
    }
}

2. Customize the view model's event delegate.

extension CustomViewController: SBUInviteUserViewModelDelegate {
    override func inviteUserViewModel(
        _ viewModel: SBUInviteUserViewModel,
        didInviteUserIds userIds: [String]
    ) {
        // Implement your code here.
    }
}

Note: You can also customize the data source using the same codes as above.