Objective-C Fundamentals

320 APPENDIX C Alternatives to Objective-C
applications in HTML, CSS, and JavaScript without having to give up too much crossplatform
portability.
A similar solution is Titanium Mobile (www.appcelerator.com/products/titaniummobile-application-development/).
A unique feature of Titanium is that it provides
access to the entire iPhone or Android UI feature set: table views, scroll views, native
buttons, switches, tabs, and popovers can all be accessed from the JavaScript in a Titanium
Mobile–based application.
With both solutions, because source code is available, if you find a device feature
not exposed to JavaScript, and you’re comfortable with writing a little Objective-C or
C, you can easily provide a JavaScript callable wrapper for the feature in question and
produce your own application-specific variant of the solution.
Ultimately, the decision of web versus native iPhone development may come down
to your own personal experience and comfort levels. If you’re a web developer, learning
how to optimize your existing web pages for viewing on the iPhone may be the
quickest route forward. If you’re a long-time C, C++, C#, or even J2ME developer, taking
the time to learn Objective-C and Cocoa to build native applications may be more
rewarding and open the possibility of code reuse from previous projects.
C.4 Scripting languages: Lua and Ruby
If an Objective-C-based application can be developed to host content written in
HTML, CSS, and JavaScript, you may wonder if it’s possible to develop similar shells to
enable development of applications in other popular scripting languages such as
Python, Ruby, or Lua. The resounding answer is, yes—although the path to App Store
acceptance hasn’t always been clear or straightforward in such cases.
One such product is the Corona SDK product from Ansca Mobile (www.anscamoble.
com). Corona enables a developer to write an application in the Lua scripting language
and place it in a predeveloped native application that performs a task similar to
what PhoneGap did for JavaScript.
Although PhoneGap is more focused on enabling web-based content, the focus of
Corona is arguably in gaming, as OpenGL-ES and similar game technologies are used
heavily in the APIs the Corona SDK exposes to your Lua script.
The Corona website offers the contents of listing C.2 as an example of the
Objective-C source code required to draw an image onto the screen using OpenGL-ES.
Although the source code is arguably worse than it needs to be, it’s hard to deny the
potential productivity gains once you compare it to the one line of Lua source code
required in a Corona application to perform the same task: display.newImage
("myImage.jpg", 0, 0).
Listing C.2
Drawing an image onscreen with OpenGL and Objective-C
NSString *path = [[NSBundle mainBundle] pathForResource:@"myImage"
ofType:@"jpg"];
NSData *texData= [[NSData alloc] initWithContentsOfFile:path];
UIImage *image = [[UIImage alloc] initWithData:texData];