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Asked: 2026-05-28T05:12:40+00:00

What’s the best design to use in an iPhone app that uses core data

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What’s the best design to use in an iPhone app that uses core data when you have several view controllers that make similar core data calls?

Currently I have an app which has several view controllers which all perform similar functions like adding objects to an entity, deleting an entity, etc. I figure there are a few ways to handle this:

  1. Each view controller has it’s own addItem:blah class. Downside is this results in some copy-pasta between the classes

  2. Create a superclass which has the core data methods, and inherit from that class. Override where necessary

  3. Create a category so all instances of view controllers have those methods without needing to subclass

  4. Create a data manager singleton which can be called. Might be useful to have this so I can queue requests and do data management outside of each view controller. Downside is this feels like a bad idea in general

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1 Answer

  1. Editorial Team

    CoreData and ViewControllers don’t need to know about each other.

    UIViewControllers are not traditional Controllers in the MVC world. They are more closely couple to Views – and I prefer to create them with this in mind,(most Apple example code has a lot of ModelController code – probably for simplicity of the examples).

    I like to create ModelControllers and leave my ViewController managing my Views, and I give my ViewControllers an instance of my ModelController.

    My ModelController will manage my Model, loading, editing, deleting etc… I still expose my Model classes to my ViewControllers, but Views NEVER leave the ViewController. You would never see a View in the ModelController.

    The advantage of this is that if you later create an iPad app – your model and how it behaves is completely independent from your ViewControllers, so when you create some new UIViewControllers for your iPad app – you can plug in your ModelControllers.

    Your ModelController could have a parent class that has your duplicate CRUD methods.

    Alternatively….

    A library called MagicalRecord https://github.com/magicalpanda/MagicalRecord adds the Active Record pattern to NSManagedObjects.

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