[SOLVED] Converting and storing JSON data into iOS Core Data

Converting and storing JSON data into iOS Core Data

Basically I'm working on an app to allow users to track their tv shows. A user can click their tv show to get a season and episode breakdown.

To achieve this, I am trying to gather JSON data from this API, and then store the data into core data. The API call is this: http://api.trakt.tv/show/summary.json/36590b30dc7d0db9ebd3153b1a989e5d/arrow/1

I can successfully store the values of: title, year, url, first_aired etc. But I can't work out how to store the season and episode information into my core data (located about half way down the JSON API call)

I have included a link to a screenshot of how I've set out my core data model: !http://i546.photobucket.com/albums/hh427/camcham/ScreenShot2013-10-17at34449AM.png

The code below is how I'm currently trying to store the JSON data into my core data (using MagicalRecords)

NSManagedObjectContext *localContext = [NSManagedObjectContext MR_contextForCurrentThread];


        Show *showp = [Show MR_findFirstByAttribute:@"sID" withValue:showID inContext:localContext];
        if (![showp.sID isEqualToString:showID])
        {
            //Create New Show in current thread
            Show *showContext = [Show MR_createInContext:localContext];
            showContext.title = showTitle;
            showContext.poster = showPoster;
            showContext.year = showYear;
            showContext.sID = showID;
            //code above this comment correctly adds right JSON info to core data and i can access and display it properly

The next part of my code I have tried to convert an NSArray to NSSet, as my 'seasons' relationship is of type NSSet, however I believe the JSON data is NSArray. I am getting the following error: * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber managedObjectContext]: unrecognized selector sent to instance 0xa22a680'

                NSArray *show = [(NSSet *)[JSONEvents objectForKey:@"seasons"] valueForKey:@"season"];
            showContext.seasons = [NSSet setWithArray:show];

The code below does not work as intended. episode.title for example, stores every single episode's title, instead of just the single title for a particular episode.

            Season *season = [Season MR_createInContext:localContext];
            season.seasonNumber = [(NSDictionary *)[JSONEvents objectForKey:@"seasons"] valueForKey:@"season"];
            season.episodes = [(NSDictionary *)[JSONEvents objectForKey:@"seasons"] valueForKey:@"episodes"];


            Episode *episode = [Episode MR_createInContext:localContext];
            episode.title = [[(NSDictionary *)[season.episodes objectForKey:@"seasons"] valueForKey:@"episodes"] valueForKey:@"title"];
            episode.overview = [[(NSDictionary *)[JSONEvents objectForKey:@"seasons"] valueForKey:@"episodes"] valueForKey:@"overview"];

So to sum it all up, I would love for someone to demonstrate the correct way to store the tv seasons and episodes from my JSON API, so I can then utilise this data in my app!

Solution

Removing the cast to (NSSet *) should fix the error.

NSArray *show = [[JSONEvents objectForKey:@"seasons"] valueForKey:@"season"];
showContext.seasons = [NSSet setWithArray:show];

instead of

NSArray *show = [(NSSet *)[JSONEvents objectForKey:@"seasons"] valueForKey:@"season"];
showContext.seasons = [NSSet setWithArray:show];