ReloadData in UICollectionView

Question

I use CoreData and want to reload the UICollectionView when I save a new entry in CoreData but the only self.collectionview.reloaddata()don´t run it reload nothing.

Thanks for your Help.

My CoreData and UICollectionView I have try it to reload the UICollectionView when clockblogalarm become a new entry:

var clockblogalarm = [ClockBlogAlarm] () {
    didSet {              //self.ClockCollectionView.reloadData()
    }
}


var mgdContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext


func loadClockAlarms () {
    let LoadRequestBlogAlarm: NSFetchRequest<ClockBlogAlarm> = ClockBlogAlarm.fetchRequest()
    clockblogalarm = try! mgdContext.fetch(LoadRequestBlogAlarm as! NSFetchRequest<NSFetchRequestResult>) as! [ClockBlogAlarm]
}



@IBOutlet var ClockCollectionView: UICollectionView!


override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)    
    self.loadClockAlarms()  
}

Here I save the Entry in CoreData. When I click the Button Done view.bottomButtonHandler{} then I want to reload the data and show it in the UICollectionView with loadClockAlarms() .

else if index == 1 {

        let view = AddClockView.instantiateFromNib()
        let window = UIApplication.shared.delegate?.window!
        view.closeButtonHandler = {[weak modal] in
            modal?.closeWithLeansRandom()
            return
        }
        view.bottomButtonHandler = {[weak modal] in
            modal?.closeWithLeansRandom()

            self.loadClockAlarms()


            return
        }

        modal.show(modalView: view, inView: window!)

    }






// MARK: UICollectionViewDataSource



override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return clockblogalarm.count
}



override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "AlarmBlogCell", for: indexPath) as! AlarmBlogCell

    cell.layer.cornerRadius = 8



    let clockblogalarms = clockblogalarm[indexPath.row]


    if clockblogalarms.lock == "ClockblogAlarm" {

        cell.Title.text = clockblogalarms.title
        cell.Time.text = "SSSSS"

    }




    return cell
}

Answer 1

Ensure the reloadData() is called in the main thread, as it is the UI-responsible action:

dispatch_async(dispatch_get_main_queue()) {
    self.ClockCollectionView.reloadData()
}