Model structure for different categories - objective-c

Question

I'm creating an app where I have different categories, and these categories has got different items that I want to display in a table view. Each item has got a title, description, url, and a image. The category has got a title and all the items that belongs to that category.
Which is the best way to create models for this structure?
I was thinking about a NSObject called Category, with a NSString for the title and a NSMutableArray for the items. And then another NSObject called Item with NSStrings.
I'm going to parse a JSON with all the data. But how can I parse the JSON objects into the right category model array?

Answer 1

Your model looks good enough. But why only NSStrings for Item. According to your description item model class should look like below:
#interface Item: NSObject{
NSString *title;
NSString *description;
NSURL *itemURL;
UIImage *image;
}
You can use NSJSONSerialization for parsing the json. For eg:
If you have a json string like following you can parse it like below:
NSString *jsonString= #"{ \"category1\": [ { \"iTitle\" : \"item1\", \"iDescription\":\"desc1\"},{ \"iTitle\" : \"item2\", \"iDescription\":\"desc2\"}]}";
NSData *data = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *jsonObj = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
If you want to parse and put it in classes you can do the following :
for (NSString *category in jsonObj) {
Category *categoryObj = [[Category alloc] init];
categoryObj.title = category;
NSArray *itemArray = [jsonObj valueForKey:category];
for (NSDictionary *item in itemArray) {
Item *itemObj = [[Item alloc] init];
itemObj.title = [item valueForKey:#"title"];
itemObj.description= [item valueForKey:#"description"];
[categoryObj.items addObject:itemObj];
}
}
To loop through a dictionary (or to access 'category1' in the string
#"{ \"tab1\": [{ \"category1\": [ { \"iTitle\" : \"item1\", \"iDescription\":\"desc1\"},{ \"iTitle\" : \"item2\", \"iDescription\":\"desc2\"}]}}"
you can use a for in loop.
NSDictionary *categoryDict = [[jsonObj valueForKey:"tab1"] objectAtIndex:0];
for (id key in categoryDict){
NSLog(#"Key : %#",key);
NSLog(#"Value: %#",[categorDict valueForKey:key];
}