TableView in MVC - how to bind view to controller data?

Question

Hi,
I have a default view in my BSP with a tableView on it. I have set the table and iterator variables. In the controller DO_INIT I am selecting the reqd data - how do I pass this data to my table view?
I have created a iterator class and implemented the required methods - how should I use this iterator class to move the data to the view.
In the DO_REQUEST method I am setting the attributes for the view - the table values and also iterator attribute, but its not working...
Thanks
Kiran

Answer 1

All right we will try this one question at a time:
>How do I use the iterator, where do I implement the std. methods of the iterator interface.
I think that has already been answered in another thread after your question. But just to be clear, the iterator is generally a completly separate class that implements the interface IF_HTMLB_TABLEVIEW_ITERATOR.  I said generally, because technically this can be any object that implements this interface.  You could implement this interface in your model, your controller, or your application class - but this is not advised.  I like to create a separate class and instaniate it either in my model or my application class.  I store the object reference as an attribute of the hosting object.  This makes the iterator easily accessible when you need it.
>How will my view know that it has to use the iterator class that I create?
It doesn't.  Nor does it need to.  The view has nothing to do with the iterator.  The iterator is not a general method for generating Extension Elemetns (that is what the BEE is for).  The iterator class is specific to the element htmlb:tableView and can only be used with this element.  The Iterator instance is passed into the tableView during the definition of this element in the view.  The class behind the tableView will then use and interact with the iterator class at the correct times.  The table will pass the correct data into the iterator object so that the iterator can pass over either the column, the row, or the cell (the three different methods of the interface) and change the rendering of the tableView.
>I am new to MVC and dont know how to create biding between view & model attribute.
Yes Data binding is done between a view and a model (the model's attributes) not the controller. Data binding is very useful as metadata about fields can be consumed automatically by UI elements in the View.  It also handles Input Handleing for you.  I can't explain the entire concept of MVC and databind in a thread posting - as that wouldn't do it justice. However there are blogs, on-help and chapters in certain BSP Books dedicated to just that topic.
>Finally is the model class & application class one & the same?
No they are very different objects with different purposes.  Application classes existed before MVC was supported by BSP.  You can have one and only one application class per BSP application.  They are used in stateful applications to store data and object references over the entire lifetime of the application.  They can also be holders for application logic that spans the entire application. However since the introduction of MVC (in release 6.20) they should take a back seat to full MVC.  MVC separates the presentation logic (view), flow and eventing (Controller) and Application Logic (Model) into separate objects.  In a BSP application you can have 0:n model objects.  Technically a model class is any standard ABAP class that inherits from CL_BSP_MODEL2.  You create them in the ABAP Editor like any other class. However the inheritance has methods that can be called by the BSP and MVC framework to perform functions like data binding.