Cooking with gas

One of the great things about the NDA being lifted is that a lot of great books about iPhone development are finally being published. It’s about time: for many months the top search hit on this site has been iphone app development. A lot of new developers need guidance.

Last week, Addison-Wesley contacted me saying that they wanted to mail a free copy of Erica Sadun’s new book, The iPhone Developer’s Cookbook. I guess that’s one of the benefits of having a web log that a lot of other iPhone developers read: I took them up on the offer since there were no strings attached.

To be honest, I wasn’t expecting to get much out of this book. After spending many months digging around in the bowels of the SDK, I thought I had seen it all. I’m happy to report that I was wrong.

If you’re an experienced iPhone developer, you won’t learn much from the beginning of the book: you already know about the application package, setting up Xcode, platform limitations, how UIKit uses MVC, and so on. If you’re new to the platform, this information will certainly be helpful and I found that it was presented clearly and concisely.

So what did I like about this book?

First off, there are the recipes. These short snippets of code show you how to do a lot of common tasks. Need to build some draggable views? Just look up the recipe “Dragging Views” and you have a few pages of pertinent information (including a brief introduction to UITouch.)

I much prefer this format over long, involved examples that are complete implementations. The recipes in this book act as a quick way to get up to speed and they help you find more detailed information in the Developer Documentation in Xcode. The recipe format gets you pointed in the right direction.

In going through these recipes I ended up learning some new things. For example, I didn’t realize that you can set the number of rows in a UIAlertView. Again, the short and sweet recipe format makes it easy to pick these things out.

There are also some clever recipes: I particularly enjoyed the one that added a UIProgressView as a subview to an empty UIActionSheet. A nice trick to leverage the existing UIKit classes in new and different ways.

But the real value of this book comes from Erica’s experience in working with the Jailbreak APIs. She goes where the Xcode documentation does not and lets us peek behind the curtains. (This book, in effect, summarizes a lot of the poking around she did during the early days of the iPhone.)

Personally, I will never use undocumented iPhone SDK calls. It’s just too dangerous: you risk not getting accepted into the App Store because you’ve broken the terms of the license agreement (section 3.3.1.) And even if you do sneak it through, what are you going to do if the unpublished API changes and breaks your app? You’ll have a hell of a lot of unhappy customers for the couple of weeks it takes to get a new version submitted and approved.

So why is Erica’s exploration into the undocumented side of the API so helpful? Because it shows us what Apple is using in their own applications. And if we need similar functionality, we can file enhancement requests using this inside knowledge.

As an example, there’s the page curl animation that is used in the Maps application. You won’t find it in the API documentation, but it’s there if you use @”mapCurl” or @”mapUnCurl” as the animation type. If you want to do that in your own app, write a Radar and let the developers at Apple know. Make sure to give them context for the enhancement request: tell them why exposing the API would make your app better.

Personally, I have written Radars for the inclusion of the UICalloutView class and UIToolbar customization functionality.

In summary, I highly recommended Erica’s book. If you’re a beginner, you’ll find code that helps get you started. For those of us who have more experience, you’ll find it to be a valuable reference for both public and private APIs.

If you’re planning to buy a copy, please make me rich with affiliate kickbacks at Amazon. Thanks!