Write your own iPhone apps for fun and profit

David M Williams
Wednesday, 09 July 2008 17:25

Opinion and Analysis

The program code files are also categorised, and you can tell from the folders “Main View” and “Flipside View” which screen they correspond to. Click on one of these files and the contents open up in the text editor on the right-hand side. This is Apple’s Objective C language. If you are familiar with the C or C++ languages you will have a head start.

Unfortunately, you really will need to come to terms with Objective C if you want to write meaningful iPhone apps. However, with the templates and the very easy interface builder you can definitely produce very attractive screens. Depending on your application’s needs maybe you can even get away solely with just building screens! I can’t imagine why you’d have to drop a line of code for a tab-paged document which simply provides static, scrollable, text - and such a database of information could well have use in its own right.

You will need to write program code for anything which is interactive, anything which performs calculations, anything which manipulates files or network content, or anything which has any degree of sophistication.

Nevertheless, no matter your level of expertise you can appreciate this next bit: click the Build / Build and Run menu. You will be prompted to save any files you’ve modified. Xcode compiles the program and then launches the iPhone emulator. You now have an iPhone running on your Mac!

The iPhone starts up ad begins running your program. If you didn’t add anything to the user interface you can still see the elements built into the template. In the flippable utility template, for instance, you will see a small “i” information button at the bottom right. Click this and the window flips to show the other side.

The iPhone emulator lets you do more than just run this one app; you can press the sole iPhone button at the bottom of the screen to play with the small range of photos, settings and contacts it has built in - not to mention use the Safari web browser. In a way it’s a bit cool to run a live, fully functional web browser within an emulated iPhone on your screen - or maybe that’s just me.

Check out the iPhone emulator menus also; you’ll see a Hardware menu which lets you rotate the iPhone to check out how your app handles that. You can simulate a memory warning, and you can perform other functions to give your code a good testing on a realistic representation of the genuine device.

To go further, alas, you need to pay for the Apple Developer program membership. This will give you the facilities necessary to actually install your app on a real live iPhone, as well as to make it available for distribution - whether for free or for profit - on the Apple iPhone Marketplace.

Well now, with this under your belt I look forward to seeing a plethora of well-crafted iPhone apps from smart iTWire readers come the end of this week!