Create the ChannelViewController, for displaying the broadcasting members of the channel

Agora-Broadcasting-ChannelViewController.swift

import UIKit
import AgoraRtcKit

class ChannelViewController: UIViewController {

    static let channelName: String = <#Static Channel Name#>
    static let appId: String = <#Agora App ID#>

    /// Using an app without a token requirement in this example.
    static var channelToken: String? = nil

    /// Setting to zero will tell Agora to assign one for you
    lazy var userID: UInt = 0

    /// Role of the local user, `.audience` by default here.
    var userRole: AgoraClientRole = .audience

    /// Creates the AgoraRtcEngineKit, with default role as `.audience` above.
    lazy var agkit: AgoraRtcEngineKit = {
        let engine = AgoraRtcEngineKit.sharedEngine(
            withAppId: ChannelViewController.appId,
            delegate: self
        )
        engine.setChannelProfile(.liveBroadcasting)
        engine.setClientRole(self.userRole)
        return engine
    }()

    var hostButton: UIButton?
    var closeButton: UIButton?

    /// UIView for holding all the camera feeds from broadcasters.
    var agoraVideoHolder = UIView()

    /// IDs of the broadcaster(s)
    var remoteUserIDs: Set<UInt> = []
  
    /// Dictionary to find the Video Canvas for a user by ID.
    var userVideoLookup: [UInt: AgoraRtcVideoCanvas] = [:] {
        didSet {
            reorganiseVideos()
        }
    }

    /// Local video UIView, used only when broadcasting
    lazy var localVideoView: UIView = {
        let vview = UIView()
        return vview
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.addSubview(self.agoraVideoHolder)

        self.joinChannel()
    }
    
    /// Join the pre-configured Agora channel
    func joinChannel() {
        self.agkit.enableVideo()
        self.agkit.joinChannel(
            byToken: ChannelViewController.channelToken,
            channelId: ChannelViewController.channelName,
            info: nil, uid: self.userID
        ) { [weak self] _, uid, _ in
            self?.userID = uid
            // Add button to toggle broadcaster/audience
            self?.getHostButton().isHidden = false
            // Add button to close the view
            self?.getCloseButton().isHidden = false
        }
    }


    required init() {
        super.init(nibName: nil, bundle: nil)
        self.modalPresentationStyle = .fullScreen
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // Add Close and Host buttons to the scene
    
    @discardableResult
    func getCloseButton() -> UIButton {
        if let closeButton = self.closeButton {
            return closeButton
        }
        guard let chevronSymbol = UIImage(systemName: "chevron.left") else {
            fatalError("Could not create chevron.left symbol")
        }
        let button = UIButton.systemButton(with: chevronSymbol, target: self, action: #selector(leaveChannel))
        self.view.addSubview(button)

        button.translatesAutoresizingMaskIntoConstraints = false
        [
            button.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: 20),
            button.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 20)
        ].forEach { $0.isActive = true}
        self.closeButton = button
        return button
    }

    @discardableResult
    func getHostButton() -> UIButton {
        if let hostButton = self.hostButton {
            return hostButton
        }
        let button = UIButton(type: .custom)
        button.setTitle("Host", for: .normal)
        button.setTitleColor(.label, for: .normal)
        button.setTitleColor(.secondaryLabel, for: .focused)
        button.addTarget(self, action: #selector(toggleBroadcast), for: .touchUpInside)
        self.view.addSubview(button)

        button.frame = CGRect(
            origin: CGPoint(x: self.view.bounds.midX - 75, y: 50),
            size: CGSize(width: 150, height: 50)
        )
        button.autoresizingMask = [.flexibleLeftMargin, .flexibleRightMargin, .flexibleBottomMargin]

        button.backgroundColor = .systemRed
        button.layer.cornerRadius = 25
        self.hostButton = button
        return button
    }

    /// Toggle between being a host or a member of the audience.
    /// On changing to being a broadcaster, the app first checks
    /// that it has access to both the microphone and camera on the device.
    @objc func toggleBroadcast() {
        // Swap the userRole
        self.userRole = self.userRole == .audience ? .broadcaster : .audience
        
        self.agkit.setClientRole(self.userRole)
    }
}