Category Archives: Cocoa

From AS3 to Objective-C: Flex vs iPhone development

Recently I’ve been given the opportunity to work full time on commercial iPhone development at EffectiveUI. The most intriguing thing about the platform for me is having access to non traditional user input mechanisms. When I was playing around with Wii remote integration on the desktop, the potential was exciting, but the ubiquity was limiting. In the same way that pc game companies develop for the keyboard and mouse first and then provide hooks for joysticks after the fact, I knew that serious Wii remote integration in a desktop app was limited. Knowing that I can write software for the iPhone that always has access to multitouch and accelerometer data from the outset really allows for unique gestures as a first class citizen within an app.

After working with some code and spending time with the SDK itself, I couldn’t help but naturally compare UI development on the iPhone with GUI frameworks like Flex or Swing, heres the things that stand out so far.

  1. I’m really spoiled by higher level languages. A good high level language like ECMAScript, Ruby, or Java rides the fine line of “Making things as simple as possible, but no simpler”. I’ve never felt constrained by the language features in these technologies, only by the apis exposed. Stepping *back* into Objective-C certainly provides more power and flexibility in the language, but there’s a loss in productivity for me that I just can’t shake. Some of this loss comes from Objective-C’s design itself, and some of it just comes from XCodes introspection ability. For instance, I’m not sure if I’ll ever get to the point where I can read these lines of Objective-C as effeciently as their ActionScript counterparts would probably look.
    NSString *aString = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"];
    UIView *contentView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
  2. Closed source UI frameworks suck. Most of what I learned about custom UI development in Flex I learned by inspecting the source code for the bundled controls. Ripping open Containers to see how layout rules are determined, or Lists to see how delegates are passed around, or the Image control to see how different display types are handled provides invaluable gems about implementing Flash apis. It has also helped me optimize the interactions of an app knowing the intentions of the developer who created the UI controls. With the iPhone SDK, you’re given documentation for the visual components, but no source to help determine how they work.
  3. Core graphics and animation is really strong. Between Quartz and the OpenGL layer there’s alot of potential for getting easy access to some of the more complex visual hacks. Although I think 3D user interfaces are prone to usability issues, the iPhone is a much better device to explore them on then a standard keyboard and mouse interface.
  4. Data binding, event listeners, and mxml. The Flash Player and Flex model provide features on top of the ActionScript language that arguably optimize UI needs and keep development more declarative. Cocoa development could really benefit from a ‘gui compiler’ that takes Objective-C to a higher level and bakes in features that support common ui design patterns.
  5. Garbage Collection. Objective-C 2.0 provides a unique system that lets you create objects that will be automatically garbage collected, or you can continue to manually manage object allocation/deallocation yourself. The concept sounds cool, but I can imagine allowing both systems to be mixed within the same project is just begging for trouble.

So far I think that Objective-C has alot of power and some really awesome features that outclass GUI features in Flash, but compared to Flex development as a whole, I’d have to say that XCode and the included visual frameworks are not as sophisticated.