App for iOS and MacOS X

I'll be creating an app that will start it's life as an iPhone app. Then a OS X application with very similar functionality will be developed. Both apps will share a lot of code base and rely heavily on content stored in Core Data, so it seems logical to me to store everything in one Xcode project.

Q1. Is this a good idea and can it be done ? What is the best way to set this up?

Q2. I'm开发者_C百科 looking to sync the Core Data content via iCloud (between the iPhone app and OS X application), can someone point me to a good source on how this works (I'm a registered Apple developer but can't seem to find it)

Q3. An iPad version may come out later, should I start with a Universal app or convert it later ?

This should be created in a single workspace in Xcode 4. I would look to create separate projects for the OS X and iOS applications, but store the shared code in another project which would have multiple targets - one for the static library for iOS and one for OS X. Each project would need to be configured to include the correct library from the shared project.

For Core Data, watch the 'What's new in Core Data for iOS' session video from WWDC 2011 (obviously requires an Apple developer account):

http://developer.apple.com/videos/wwdc/2011/includes/whats-new-in-core-data-on-ios.html#whats-new-in-core-data-on-ios

I would take a look at the Chameleon project which may help you out for your OS X port.

http://chameleonproject.org/

Also the iCloud stuff should not be talked about here as it is under NDA.

As for the universal it is up to you, you can convert to Universal at a later stage if you don't want to do the work now.