My first iPhone application

Last month I wrote about some resources for learning Objective-C that I was using to learn how to write iPhone applications. Judging by the number of comments on that article, I thought that I should write a follow-up post about my progress and the status of my first iPhone application.

Since I had a few programming classes in college (VB, C++), the logic of loops and decision statements was not a big hurdle. By using the learning resources like screencasts and books, I was able to get a better grasp of object-oriented programming (OOP) in general, and of course the syntax specific to Obj-C. I became familiar enough with Xcode just by using it for demo programs, and I used the wealth of iPhone developer resources from Apple to use the iPhone SDK. After paying $99 to Apple to enter into the iPhone Developer program, I was then able to access the forums; they were helpful in figuring out specific things (like how to preset a UIPickerView object).

When I felt comfortable with the basics, I started writing my first iPhone application. My girlfriend recommended that I create an application that keeps track of how much money is in my piggy bank since I'm always tossing spare change into it but never sure of the total (and therefore never sure when to cash out). This seemed like a simple enough idea to program, so I started on it shortly after I wrote the Obj-C article (mid January). I quickly figured out how to use Interface Builder to add buttons for coins and linked the touch of a coin to the addition of a coin value.

And then I made a rookie mistake... using floating point numbers for representing money. In my program testing, every so often my math would be $.01 wrong. I finally realized this was because I was using float values and the addition of money was not being done correctly. So I switched to using integer math for the entire program and solved that problem. When the math logic was complete, I spent time improving and beautifying the user interface with graphics and a color scheme.

With my first program complete, I decided to try to submit it to Apple for review in hopes that they would put it on the App Store. I had to download and install a Distribution Certificate to sign my Obj-C code, build the program for the proper iPhone OS version (I chose 2.0), and create a .zip of the .app that Xcode built. I then had to assemble my screenshots, App Store artwork, and application description for upload to iTunes Connect. I submitted the application, and about six days later it was approved and is now available in the App Store (along with 20,000 others!).

My personal goal of creating an iPhone application and getting it on the App Store is complete, but I will most likely work on more applications. If you're interested in using my first iPhone application, you can download my Piggybank application in the App Store for $0.99US.

[Editor's Note: Todd wrote Piggybank on his own time and it is not an 'official' TUAW application; this post is not an endorsement or review of the app, but a perspective on the development and submissions process from Todd's point of view.]
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