UITableView with asynchronous loaded images and stored locally using Core data

I am working on an application that displays a list of venues containing a name, address and an image fetched from a REST Webservice i built. The image is specified as a URL string pointing to an actual file on the server. The images are 180x180 px JPEG compressed.

I am trying to display this list in a UITableView with a custom cell, loading everything asynchronously and storing them using core data. I defined a core data entity with various properties and an “image” property of type “Binary Data” with external storage to hold the downloaded image for each venue.

I tried various approaches but most of them led to a sluggish scroll and a not so good experience.

The best results i got by doing the following:

1. create 2 properties in UITableViewController
   • NSArray localVenues (holds instances of core data entities without the “image” property)
   • NSMutableDictionary localVenuesImages (holds pairs of VenueID - NSData image)
2. in viewDidLoad:
   • check local storage for any saved entities, if found i load them in localVenues and localVenuesImages
   • if no local saved entities are found, the list of venues is downloaded asynchronously and stored in localVenues and in local core data database
3. in cellForRowAtIndexPath i pass to the cell (via a function called configureCellForEntry) both localVenues and localVenuesImages
4. in configureCellForEntry i do the following
   • set all the text labels on the main thread
   • dispatch a secondary thread that:
     • checks if an image exists in localVenuesImages for the given VenueID, if true it creates a UIImage with it, and switches to the main thread to display it
     • if no image is present in localVenuesImages it downloads it, then switches to the main thread and:
     • adds it in localVenuesImages
     • saves it to it’s corresponding core data entity
     • displays it

I am wondering if there’s a better way to do this.

Thank you.