iPhone development tools that work the way you do

You don't need to master Cocoa and Objective C to create killer iPhone apps. Rhomobile, PhoneGap, Appcelerator, and Ansca tools leverage standard Web technologies and still tap native features

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The Rhomobile development process is just like building a Ruby on Rails Web application. The phone is both server and client. It has a split personality and is always talking to itself.

The Ruby on Rails developer will feel right at home. You craft your user interface in HTML with embedded commands in .rb and .erb files, then fire them off by typing rake in the command line. You can also use Xcode on the Mac and Eclipse when developing for other platforms. The Rhomobile scripts compile the Ruby code, bundle everything together into an application, sign it, and fire up the simulator for you. The interaction and debug cycle is pretty quick.

The database is not MySQL or an embedded database, but Rhom, an object mapping tool with some basic queries. It's not unlike some of the stripped-down databases like CouchDB that are becoming common. Rhom runs on the phone itself, but it interacts with RhoSync servers using AJAX calls, a technique that allows the local database to back up and update itself with distant servers. This RhoSync tool is also a Ruby on Rails application that you can install on your server. It can serve data to Rhodes applications.

I struggled through several basic glitches on my Mac. The application was pretty sensitive to the characters used to end lines, a problem that went away once I forced my editor to go with Unix endings. There's also no simple mechanism for handling 404 errors. The application just crashed whenever it couldn't find a page. It works better if you stay within Xcode. But I found work-arounds for all of the glitches and built some simple applications without problems.

While the goal is to build a home that will be very familiar to the Ruby on Rails programmer, the Rhomobile world is not the same as Rails. If you love to do clever meta programming using the eval instruction, you'll be frequently thwarted because Rhomobile bends over backward to prevent developers from adding new features or functions. Apple wants to thoroughly scrutinize each application before it launches, and functions like eval make it impossible to, well, evaluate the code beforehand. So Rhomobile has left eval out of the Rhodes framework.

Rhodes is also a bit lighter than many of the traditional Ruby on Rails frameworks. Rhomobile left out XML and Web services, for instance, to save space. After all, the application you create is constantly talking to itself, so there shouldn't be the same need to work with outside standards. If there's no XML parser in the client layer, then don't use XML on the server layer. Tags are the equivalent of arteriosclerosis here.

Rhomobile is also adding new features that let the Ruby/HTML programmer interact with the iPhone's capabilities. It's built out the links to the geolocation information, the contact manager, and the camera. The date/time manager and the ring tone manager are coming.

You can build Rhodes apps from the command line with rake, but I found that the Xcode integration was easier to use.
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