Robotlegs MVCS: Walkthrough of an AIR Twitter Client
Here is the "completed" project on Github.
This is a roughly 25 minute walkthrough of wiring together a Twitter client using the Robotlegs AS3 Micro-Architecture MVCS implementation. It covers setting up the context, using commands, mediating composite view component, granular view component mediation, and retrieving data from a service.
Apologies in advance for the ambient noise. 4 kids, 2 dogs, and a busy wife does not make the perfect sound booth 
I am considering expanding on this example and creating a start to finish video series creating a full Twitter client with Robotlegs. This would cover the actual component building, wiring everything together, working with data models (local storage, etc), and refining the application to use the advanced features available with the Twitter API using TDD the whole time for development. Is this something that you'd be interested in?
Robotlegs IoC/DI Flex Framework Examples Updated
Live demos are available on robotlegs.org here
Acme Widget Factory:
The Acme Widget Factory is modular example and deals with loading multiple modules into a shell and communicating between those modules. The shell and each module has its own context.
Lazy Stack:
Lazy Stack is an example of deferred instantiation of Flex components, and how this is handled by the Robotlegs framework.
Wheres Window:
Where's Window is a simple example to show how to mediate and communicate between a set of instances of the same view component that have individual mediators. In this case, the view components are windows in an AIR application. This uses a proxy to register and manage the currently open unique windows. I am going to write a more detailed breakdown of this particular example soon.
The Elevator Pitch
Robotlegs is an IoC/DI container that is modeled on the PureMVC application structure. It is designed to be MVCS, model-view-controller-service, providing metadata dependency injection across these layers. While following the well organized approach of PureMVC, it eliminates the use of framework singletons and takes full advantage of the Flash Platform to keep the dreaded boiler plate code to a minimum. Eliminating these singletons makes unit testing and TDD much easier, which can be a real struggle when trying to isolate classes for testing where these singleton dependencies exist. Robotlegs is fast, clean, and perhaps more importantly fun to work with. There is a smorgasbord of architectural frameworks available for Flex/AS3, but Robotlegs is worth a look even if you are sick of looking at architectural frameworks.
Unit Testing: IoC/DI, Robotlegs and FlexUnit 4
I've been reviewing the various IoC containers available for Flex/Actionscript. One of the benefits of IoC and DI is that it greatly facilitates unit testing. By injecting our dependencies into our applications actors, we are effectively isolating them from the other classes that make the application function. "So what?"
In computer programming, unit testing is a software verification and validation method in which a programmer tests that individual units of source code are fit for use. A unit is the smallest testable part of an application. In procedural programming a unit may be an individual program, function, procedure, etc., while in object-oriented programming, the smallest unit is a class, which may belong to a base/super class, abstract class or derived/child class.
Ideally, each test case is independent from the others: substitutes like method stubs, mock objects, fakes and test harnesses can be used to assist testing a module in isolation. Unit tests are typically written and run by software developers to ensure that code meets its design and behaves as intended. Its implementation can vary from being very manual (pencil and paper) to being formalized as part of build automation. -wikipedia unit testing entry
To effectively unit test classes, we want them to be as isolated as possible. The class needs to stand on its own and have its functionality vetted to ensure that it behaves as expected. When we start to test how our classes behave together, we have entered the land of integration testing. Integration testing is a worthwhile pursuit also, but before we get to that point, we really want to ensure that our classes are solid by themselves.
Using the example in this Robotlegs Image Gallery demonstration, we are going to test a couple of the classes that make up the application. The demo isn't complex. It has a very simple model, a single service, and just a few views. In fact, it might even seem like a waste of time to unit test a simple example such as this, but the concepts are applicable to larger applications where the benefits of this type of testing really start to pay off.
FlexUnit 4 is the framework that is used here. It provides very handy asynchronous testing, meta data support, and a whole bucket of stellar features that I won't even begin to scratch the surface of. FlexUnit 4 also comes with a graphical testrunner interface:
Robotlegs AS3: A Dependency Injection Driven MVCS Framework for Flash/Flex – Inspired by PureMVC
The quest for a Dependency Injection container continues. The most recent stop on this exploration of the available options has been Robotlegs. Robotlegs AS3 is a DI driven MVCS framework for Flash/Flex inspired by PureMVC. Being a huge fan of PureMVC, this caught my attention immediately. Robotlegs professes to be a framework like PureMVC, but without all the Singeltons, Service Locators, casting and boiler plate we have all come to love. Better yet, it delivers on these claims.
Source for this demo available on github...
