Develop an iOS App for Cydia

Question

How can I start developing simple iOS tweaks for Cydia?

What's the difference in compiling an app for the official App Store and Cydia?

Bruner

Well, the biggest difference is App Store distribution. Is there a particular reason you want to work outside of Apple's sandbox? (Just curious.) – Storied

Do you have experience doing App Store development? Any Objective-C experience at all? – Storied

... Well, first off, modifying the Springboard is not a simple task at all. But more importantly, Objective-C is nothing like Java or C#. You really should read up on it. – Storied

Answer 1

Developing a tweak is quite different from developing a self contained app. If you want to do it all yourself, read up on Objective C runtime programming. However, this is not how the vast majority of tweak developers do it, as there are several easier options.

If you have experience with Objective C (enough to be able to develop an app), there isn't a whole lot more you need to know to make a tweak. Dustin Howett, a developer who has made several tweaks for Cydia, made a tool called theos which vastly simplifies the process. You can read up on it here. There is also a very active IRC channel at irc.saurik.com #theos. Finally, you may want to check out the github pages of some popular tweak developers that use theos, so you can better understand the syntax (chpwn, DHowett, rpetrich).

Those three methods are how I learned to write tweaks, and once you understand theos it is really quite simple. theos also has systems for creating self contained apps as well as other plugins, so download it and see what is best for what you want. A quick google search will also turn up several useful theos tutorials (1, 2). Good luck!

One final thing to note is that you may want to hold off on developing for a couple weeks, the reason being that Apple may be releasing iOS 5 soon and things could change, as well as the fact that everyone on the #theos IRC will refuse to help with problems pertaining to iOS 5.

Kneeland

Theos is definitely the most common method, and is by far the easiest to use. There are varying levels of complexity if you want a more involved approach (read up on CaptainHook and Obj-C runtime programming) but since you have little/no experience with Objective C theos is the way to go. Everyone on that IRC channel is extremely newbie friendly, so you can go on there and ask them what the best way to get started is. – Kneeland

iOS 5 framework headers aren't really available anywhere, you'll have to dump those yourself. As for the iOS 4 headers, ask on the IRC for help. I forget where they are but someone has a link on there to them. Also ask there for instructions on how to dump the headers yourself. – Kneeland