Document Based Apps: Defining Custom File Extensions | Ray Wenderlich

When writing a document based app, Xcode allows you to define your own file extension. This screencast will walk you through the process.

This is a companion discussion topic for the original entry at

In this series, will you teach how to have a individual core data db PER document?

I already know how to code a global core data db. But i have a need for 1 document = 1 core database saved in the doc bundle?

Hi hows it going. Yes I bought a book and am coding with it its a very good swift 3.0 book but I am programming it using 4.0 swift. Now I’m having a problem. The problem that I’m having. it wants be to turn the assets.xcassets folder into a images.xcassetrs folder. I do that and then.

when I try to compile the program it gives me an error saying this, "None of the input catalogs contained a matching stickers icon set or app icon set named, “Applcon”

please tell me and show me the corrections I need when I say I need help finishing this programming technicality.

Hi Maverick, You posted this in a screencast topic. Can you please specify which book that you bought and which chapter is causing the issue? Thanks

Yes thanks bd. The book that I bought is called Beginning swift games development for iOS. its made by James goodwill wesley Matlock. I appreciate this BD. I can’t go forward in the book, because I don’t understand what this part is saying. Take care. I look forward to your reply.


Oh yeah I’m on page 15. I’m only on chapter 1.

On second thought never mind. I figured out how to do it by myself. Thanks anyways Bd.


scene = gameScene(size: skView.bounds.size) I have a question what does GameScene in this line mean or refer to.

var GameScene = SKScene(size: CGSizeMake(320.0, 568.0)) why isn’t CGSizeMake used in Swift because it was available in Swift 3 but not available in Swift 4.


Hi Maverick, you’re posting this in the wrong topic. Check out this forum instead:

Please check out this SpriteKit tutorial when you get a chance:

I hope it helps. Thank you! :]