properly implement subviews in Cairngorm micro-architecture

[kofi addaquay]

got a question on how to properly implement subviews in Cairngorm if anyone has experience building flex applications using this mvc architecture. my question is how do you implement changing component subviews in cairngorm. i know how to implement changing main views subviews, but i am not sure of how to properly change subviews which are within the main views subview. do i bind this to the modellocator as well...or implement it locally. not sure.. thanks

Kofi

[kofi addaquay]

whew found a way

in your model package, create a new model to hold the states of your viewstack component ...i created one like this...

Code:

package com.perfect.model
{
public class ProgrammingTabWorkflow
{
public static const PROGRAMMING_DEFAULT_VIEW:Number = 0;
public static const PROGRAMMING_MANAGE:Number = 1;

[Bindable]
public var programmingWorkflowState:Number = PROGRAMMING_DEFAULT_VIEW;
}
}

then in my panel...created a view stack and set a binding to the selectedChild. like this

Code:

selectedChild="{getSelectedChild(workflow.programmingWorkflowState)}"

getSelectedChild is a function that returns a container. the viewstack state is changed based on what is returned from the function

[papachan]

Thats a cool tip Kofi. thanks.

[kofi addaquay]

great! in that case let me put the getSelectedChild here so its fully clear. below you will see what container gets called.  progDef and progTemplate and the names of the ids of the viewstack components. enjoy

Code:

private function getSelectedChild( workflowState:Number ):Container
{
switch ( workflowState )
{
case ProgrammingTabWorkflow.PROGRAMMING_DEFAULT_VIEW:
return progDef;
case ProgrammingTabWorkflow.PROGRAMMING_MANAGE:
return progTemplate;
}
throw new Error("Invalid Workflow State");
}

[Jorge Solis]

I found this problem while working with Cairgorm and yes, you can do some tricks to allow databinding works as expected following the rules (in fact an example for deferred instantiation in PureMVC examples use the same approach for ViewStacks) But basically I find that sometimes this not really helpful when managing lots of little details about views.
I explain this in detail here: http://www.cristalab.com/tips/cairngorm-problemas-para-actualizar-la-vista-c66243l/ ... but sorry ... is in spanish. Basically the trick is to pass an extra callback to the Event, that is carried by the controller, command, delegate and finally invoked in the view to do extra visual stuff (show a confirmation message in my example)
I have finded a lot of little visual tasks that could use this way, and in fact previous versions of Cairgorm have extra classes called ViewHelpers to do this kind of things

Jorge

[kofi addaquay]

ViewHelpers were definitely helpful. but they have be deprecated. I wish i could read spanish ) i am studying it..but not good yet. Its always good to know the little tricks other people have discovered and implemented. but i can get a good idea when you say pass an extra callback to the Event. 

[kofi addaquay]

i thought i should put this link here...as i run into binding problems using selectedChild

http://www.russback.com/adobe-flex/binding-selectedchild-of-a-viewstack-in-mvc.html

[papachan]

In Mate Framework, you dont even need to give the event callBack. The eventMap controller do the job. It map all the event handlers and directly give the right methods to be actualized. Its magic !

[kofi addaquay]

thats really sweet. !

have you heard of robotlegs?? i hear its the real deal... i think that might be the framework i choose to learn besides puremvc and cairngorm.

[Jorge Solis]

I have used it in my last piece, it's a nice one, and you don't need to cast all events as in pureMVC

Jorge

[kofi addaquay]

ah really Jorge?? i love puremvc thats why i choose that framework. its interesting to see actionscript adopt java design patterns..very interesting. i have been currently looking at the documentation and is it look awesome.
what is the learning curve like?

[Jorge Solis]

If you have worked with a couple of frameworks, Robotlegs is a couple of days away or less if you have no childrens like me

Jorge

[kofi addaquay]

haha! no children on my end Jorge.

i need to dig into the docs this weekend then! thanks Jorge...i am glad to know you have already completed a project using this. i can BUG you with questions. yaay. thanks

Kofi