iOS provisioning and signing overview

I am relatively new to iOS development and seem to struggle with the provisioning a开发者_开发百科nd code signing process. I always seem to have warnings of some sort and usually resort to a shotgun type approach to my provisioning settings.

Is there a good overview of the whole provisioning and code signing process? The type of questions I would like to see in said overview would be like:

• what is code signing?
• what is a provisioing profile?
• why are these necessary?
• what are some common errors and their solution
• what is the bundle id for?
• what is the app id for?
• and is a certificate?

and most importantly ...

• what happens with these components when I click "build" in Xcode?

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I also faced these problems more than a couple of times with code signing. So I tried to understand these with some experimentation and reading. Here is my documentation for the same:

Understanding iOS Code Signing.

I will be following it up with common troubleshooting points soon. These will mostly include checking your Keychain app for valid certificates.

As for your most important question, when you "build and run", by default, the "Debug" build configuration is used. These are set in the "scheme". In xcode 4, select "Edit Sceme" in the drop down where you select the device/simulator version for testing, and check various schemes.

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Many of your questions are answered in the iOS developer portal, or in the Standard Program User Guide. Wikipedia is a good resource for general concepts like code signing and certificates.

The short answer to the question about why apps have to be signed is: because Apple says so. A slightly more helpful answer: it protects the user, the developer, Apple, and the network provider by ensuring that the apps installed by the user are identical to those distributed by their respective developers; the device will refuse to run modified apps.