Learning a whole new programming system can be a lot like getting a sip of water from a fire hose. So take your time and, once you have a solid footing in Objective-C and Cocoa touch programming, it's time to venture out on your own.
In very general terms, your app development cycle should look something like this:
1. Spitball your app concept. Use big broad brushstrokes and create a beginning app design document. Slowly flesh in all of the details of your app. Consider graphics, multimedia, fonts, colors, layout, organization, program flow, and app goals. The more detailed this document becomes, the better your app will work.
2. Install the SDK. Inside this massive 1.5GB+ download is the complete Apple Xcode Cocoa development environment. Supporting Xcode is a fistful of utilities, documentation, and Mac OS sample code. If you wish to experience the full flavor of iPhone development, you will need an active net connection for downloading sample code and additional reference library materials. This Web connection is not mandatory for Xcode operation, however.
3. Open Xcode and create your project. There are several project templates in Xcode that will ensure that you don't botch this step.
4. Build your interface. What could be easier than drag-and-drop interface design? Integrated into Xcode is a visual development utility called Interface Builder. Inside Interface Builder you can develop the complete look and feel for your app without writing a single line of code.
5. Code it. If Interface Builder is the skeleton and flesh of your app, code is the blood and nervous system. Without code, your app is just a pretty lifeless blob. Write it tight and write it clean.
6. Build it and it will run. Your first level of app testing should be performed with the Xcode-friendly iPhone Simulator. When you select "Build and Go" in your project, Xcode will compile your code and automatically launch iPhone Simulator. This Xcode utility is ideal for quickly evaluating the basic flow of your app, but it is not a substitute for actual testing on both an iPhone and an iPod touch. In fact, this would be a good time in the development of your app to create a "test team" for your project. In order to add testers to your project, you must obtain a Provisioning Profile from the iPhone Program Portal. Access to this portal is granted with your iPhone Developer Program subscription. Use this capability wisely. Have your project testers write and orchestrate testing scenarios for your app. This process will be simplified with the creation of a full-bodied app design document from step 1.
7. Get testy. In order to test your app on a real iPhone and iPod touch, you must code-sign your app. These certificates are obtained from the same iPhone Program Portal that you used in step 6. Getting your app to successfully code-sign and load on a real device can be difficult. Here are four tips to guarantee your app will run on a test device:
Once you have a successfully compiled app bundle (note: the icon for this bundle might have a white international "no" symbol -- the circle with a slash through it), send it AND the appropriate Provisioning Profile to your tester(s).
8. Fine-tune. After all of your testing has been successfully completed, use special Xcode utilities for measuring and tuning your final app. This final step will ensure that your app will be a good citizen of any iPhone and iPod touch.
Coming up, our third and final episode will take this little piggy to market! Watch the Apple iTunes App Store and monitor our progress.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.