How to display a custom loading indicator in a Group Channel ViewController?

[lookdeceline]

This post walks you through how to display a custom loading indicator in a Group Channel ViewController.

Steps

1. Create a subclass of SBUGroupChannelViewController.
2. Define your loading indicator
3. Set up your loading indicator
4. Override shouldUpdateLoadingState(_:) method, which is a delegate method of SBUCommonViewModelDelegate. This is where you can add your custom actions related to the loading indicator.

// 1. 
class GroupChannelViewController: SBUGroupChannelViewController {
    // 2.
    let loadingIndicator = UIActivityIndicatorView(style: .large)

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 3.
        loadingIndicator.color = .gray
        loadingIndicator.hidesWhenStopped = true
        loadingIndicator.center = view.center
        view.addSubview(loadingIndicator)
    }
    
    // 4.
    override func shouldUpdateLoadingState(_ isLoading: Bool) {
        if isLoading {
            loadingIndicator.startAnimating()
        } else {
            loadingIndicator.stopAnimating()
        }
    }
}

5. Before your custom SBUGroupChannelViewController is presented, set it in the SBUViewControllerSet.
6. Also, set SBUGlobals.loadingIndicator.groupChannel.cachedMessages to true. This is because by default, a loading indicator is not shown while loading the cached channels.

// Somewhere like AppDelegate.swift
 
// 5.
SBUViewControllerSet.GroupChannelViewController = GroupChannelViewController.self
// 6.
SBUGlobals.loadingIndicator.groupChannel.cachedMessages = true

Result