Since I have no prior knowledge of the programmes I’m going to use, I decided it would be best to ask around. There seemed to be many program me names involving the design of an application, so I specifically decided to ask what was adviced to me in class. here are the feedbacks;
The difficulty you’re going to have if you have only coded Java is pointers and memory management. Memory management isn’t conceptually hard as it’s simply (!) a question of keeping track of what you are allocating and releasing, plus XCode seems to come with good tools for detecting leaks (although I haven’t used these in anger yet) – and as iPhone programs are relatively small it’s not like coding a big system program where this can be extremely tough. The major conceptual difficulty you are likely to have is simply getting your head around pointers as they are used extensively (as in just about on every line of code) and you do need to grok these completely. One of Joel’s reoccuring themes on the podcast is the difficulty some coders get using pointers, so I’d recommend you take that carefully and possibly pick up a good book – perhaps the original K&R.
To answer your question the biggest hurdles are understanding the conventions (Delegate pattern, Categories, etc.), getting a grasp on memory management, and working with XCode (a good IDE but definitely steps behind Eclipse and IntelliJ).
I came out of college as Java developer. My first (real) job was Mac Development. Transitioning from a language I know (my starting point was Java) to something like Objective-C was fairly easy, code-wise. To maximize your time developing iPhone / Mac Applications, you have to make use of XCode and Interface Builder. Once you get the hang of attaching events and GUI outlets (the objects your UI want to communicate with), you’ll be set for normal iPhone app development.
Here are the steps I went through learning Objective-C (the programming language for iPhone development) having my Java background:
- Learn the basic OC object-oriented concepts. Subclassing (Inheritance), protocols (Java Interfaces), object properties (Bean properties), methods (you have to explicitly indicate the “parameter entry” labels, unlike in C / C++ / Java where you guess the parameter ordering).
- Understand the difference between Objective-C, Cocoa, Aqua, and C. Then learn about how to use frameworks. Frameworks are pretty much the same as Java Packages.
- Familiarize yourself with using these Foundation classes: NSString, NSArray, NSDictionary, NSSet, NSURL, NSAutoreleasePool.
- Study more about Interface Builder. I thought before that the Visual Basic way of programming limits the programmer. I was wrong. It is better you “visualize” the app first before you get the hang of how things go in it. Take note about the keywords IBAction (analogous to making an EventListener), Outlets (you only have a few objects “exposed” for your UI elements), Views (UIView in case of the iPhone, everything that’s “visible” in the application can be considered a “view”), and Controllers (there are ready-made controllers that you could use to populate Table Views, flip Card Views, etc.).
- Learn how to deploy your app through the iPhone Developer Portal. You cannot send any iPhone app to any device if you don’t have this “right”. Yeah, I know it sucks, but you have to go through this process, anyway, if you want to sell your apps.