How to use NSManaged object class using NSObject class

Question

I have NSObject class name TrackInfo which contains tracks info like name , artist name,thumb image etc.

I use this class as downloading data and save information to that class after parsing data. Now I have another tab in which, I have to show some data. This is same kind of data like trackInfo. But when app is in OFFLINE, I have to make NSManagedObject. It is same as trackinfo.

Can I use NSObject class instead of NSManagedObject or Vice-Versa ?

What I basically wants to do is, I have to display track info from one class either Trackinfo (NSObject class) or NSManagedObjectClass which is used to save data when app is in offline.

Answer 1

Short answer is yes, you can. How? You can find a useful discussion Organising Core Data for iOS.

The long answer can be grabbed within the documentation.

NSManagedObject is a generic class that implements all the basic behavior required of a Core Data model object. It is not possible to use instances of direct subclasses of NSObject (or any other class not inheriting from NSManagedObject) with a managed object context. You may create custom subclasses of NSManagedObject, although this is not always required. If no custom logic is needed, a complete object graph can be formed with NSManagedObject instances.

A managed object is associated with an entity description (an instance of NSEntityDescription) that provides metadata about the object (including the name of the entity that the object represents and the names of its attributes and relationships) and with a managed object context that tracks changes to the object graph. It is important that a managed object is properly configured for use with Core Data. If you instantiate a managed object directly, you must call the designated initializer (initWithEntity:insertIntoManagedObjectContext:).

About your question, it depends on what you need to achieve. If your goal is to perform a sync mechanism between your device and the server, you should set up 1) a model with a TrackInfo entity 2) a Core Data stack that relies on a persistent store like SQLite. Then you should modify TrackInfo to take into account modifications to that entity. For example, a dirty flag property (0 or 1) or a timestamp. When you do a modification on your TrackInfo you update that property. When the connection is restored you need to query against that property and sync with the server. If you choose the timestamp, the server should say what is the latest timestamp to query against.