I am using NSFetchedResultsController to track and load UITableView with two sections(based on available true or false) using data from coredata entity. Coredata entity is populated by azure syncTable pull method. I call fetchedDataController?.performFetch() from ViewDidLoad() method in VC. Data is divided into two sections - section 1 available is false, section2- avaliable is true in the entity data.
Here is code snippet of NSFRC initialization:
lazy var fetchedDataController: NSFetchedResultsController<Product>? = {
let req = NSFetchRequest<NSFetchRequestResult>(entityName: "Product")
req.sortDescriptors = [NSSortDescriptor(key: "available", ascending: true), NSSortDescriptor(key: "createdAt", ascending: false)]
guard let dbContext = self.appDelegate?.managedObjectContext else { return nil }
let controller = NSFetchedResultsController(fetchRequest: req, managedObjectContext: dbContext, sectionNameKeyPath: "available", cacheName: nil) as? NSFetchedResultsController<Product>
controller?.delegate = self
return controller
}()
Issues: 1. Even there is update in entity row data FRC delegate methods are not fired automatically. Like I changed available from true to false in the backend and did a SyncTable.pull, I can see that coredata table is updated with latest data( I opened the .sql file and able to see the data)
- To overcome workaround I called perform fetch every time I do a pull, in this case when I scroll down to section 2 app is crashing with index error, that means it is not updating the table section and rows properly.
Delegate methods implementation:
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
self.tableView.beginUpdates()
}
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
self.tableView.endUpdates()
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange sectionInfo: NSFetchedResultsSectionInfo, atSectionIndex sectionIndex: Int, for type: NSFetchedResultsChangeType) {
let sectionIndexSet = IndexSet(integer: sectionIndex)
switch type {
case .insert:
self.tableView.insertSections(sectionIndexSet, with: .fade)
case .update:
self.tableView.reloadSections(sectionIndexSet, with: .fade)
case .delete:
self.tableView.deleteSections(sectionIndexSet, with: .fade)
default: break
}
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
switch type {
case .insert:
if let newIndex = newIndexPath {
self.tableView.insertRows(at: [newIndex], with: .fade)
}
case .update:
if let index = indexPath {
self.tableView.reloadRows(at: [index], with: .fade)
}
case .move:
if let index = indexPath {
self.tableView.deleteRows(at: [index], with: .fade)
if let newIndex = newIndexPath {
self.tableView.insertRows(at: [newIndex], with: .fade)
}
}
case .delete:
if let index = indexPath {
self.tableView.deleteRows(at: [index], with: .fade)
}
default: break
}
}
I am stuck into this any help is appreciated.
