How to update UI when app is in foreground?

Question

When my app is active and I receive a silent notif from the server to update my tableview with the new data, I'm calling the following function in which I'm making a request to the server to bring latest data and then reload that specific row.

func updateCell(path: Int, messageId: String) {
    let indexPath = IndexPath(item: path, section: 0)
    if let visibleIndexPaths = mainTableView.indexPathsForVisibleRows?.index(of: indexPath as IndexPath) {
        if visibleIndexPaths != NSNotFound {
            if let id = self.userData?.id {
                let conversationID = String(describing: id)
                ServerConnection.getSpecificMessage(conversationId: conversationID, messageId: messageId) { (dataMessage) in
                    if let message = dataMessage {
                        self.chat[path] = message
                        self.mainTableView.beginUpdates()
                        self.mainTableView.reloadRows(at: [indexPath], with: .fade)
                        self.mainTableView.endUpdates()
                    }
                }
            }
        }
    }
}

My problem is when my app is in the foreground the flow doesn't work anymore because of the API request which can't be done in the foreground / background .

Console log shows :

load failed with error Error Domain=NSPOSIXErrorDomain Code=53 "Software caused connection abort"

I've tried to modify my function with

let state = UIApplication.shared.applicationState
    if state == .background || state == .inactive {
        NotificationCenter.default.addObserver(self, selector: #selector(self.reloadData(_:)), name: NSNotification.Name("BackgroundReload"), object: nil)
    }

and posted this "BackgroundRelod" notification in AppDelegate

func applicationWillEnterForeground(_ application: UIApplication)

but this will always trigger my function even though I didn't receive any silent notification to update the UI.

Answer 1

You should not depend on background mode in updates , you need to only modify a var say needsUpdate whenever a silent notification comes in background here

func application(_ application: UIApplication,
                 didReceiveRemoteNotification userInfo: [AnyHashable : Any],
                 fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {

Then

NotificationCenter.default.addObserver(self, selector: #selector(update), name: UIApplication.willEnterForegroundNotification, object: nil)

@objc func ppp(_ no:NSNotification) {

    if needsUpdate {

        // pull here
    }

}