Part 4 of “Event-Driven” Tutorial on the WD-ABAP Component WDR_TEST_UI_ELEMENTS.

This post resumes the “experiential” or “event-driven” tutorial on how to use the SAP-delivered WD-ABAP component WDR_TEST_UI_ELEMENTS as a pattern for a

component that displays

. Although there have been three posts in this tutorial to-date:

“Procedural” Recap of What’s Been Learned So Far in “Experiential” (“Event-Driven”) Tutorial on WD-ABAP component WDR_TEST_UI_ELEMENTS

The class infrastructure of WDR_UI_TEST_ELEMENTS is exquisite for lazy cloning and change-ups.

Experiential vs Procedural Tutorials: “Breaking” WDR_TEST_UI_ELEMENTS to Learn From It.

one need only read the most third and most recent (“Procedural Recap”) in order to understand what has been learned so far, i.e. what has been done so far and why. On the other hand, unless one takes the time and trouble to read the first and second posts as well, one really misses the essential point of this “experiential” or “event-driven” tutorial – namely – to learn how to do WD-ABAP without reading the documentation, going to class, or drilling through procedural tutorials.

Documentation, class, and procedural tutorials

all integral parts of the WD-ABAP learning experience, and one shouldn’t attempt the kind of “event-driven” self-tutorial I’m documenting here

one has gone thru the excellent WD-ABAP procedural tutorials already written by SAP and SDN folks. This is because going thru these procedural tutorials will make one’s fingers smart at WD-ABAP editor navigation, as well as providing a rough initial idea of how WD-ABAP actually works. In fact, it is a good idea to do

WD-ABAP procedural tutorials before trying an “event-driven” self-tutorial, if you are a bear of as little brain as me and have to be hit over the head by repetition before you really understand anything. (Note: the phrase “bear of little brain” is from the great children’s classic “Winnie-the-Pooh” – (re-)reading it is a great way of getting some relief from the pressures of seeing how quickly one can become effective in WD-ABAP.)

Anyway, at the end of the third post in this series, the clone WD-ABAP component ZWDR_TEST_UI_ELEMENTS had been successfully modified to display not only the SAP-delivered trays and links in the left-hand side tray view, but also the following “custom” trays (metadata libraries) and links (metadata library members):

(custom tray)

Vendor Database (custom link)
Open Item Balance Audit Trail (custom link)
Historitcal Balance Audit Trail (custom link)
Condition Record Selection (custom link

(custom tray)

Document Numbers by Cost Center (custom link)
Projects to Activities (custom link)

(custom tray)

Balance Sheet/Income Statement (custom link)
Maintenance/Mechanical Services (custom link)
Manufacturing Operations (custom link)

And therefore, the next step in modifying

is to get this clone component to display the correct right-hand-side tree-view when one of the custom links is selected. To make this objective clear, it is important to note that:

i) the SAP-delivered component

opens with the

library selected and the

link selected, so that the right-hand side tree-view already displays the “aggregation” for “

“.

ii) If one then clicks on a different link within the

tray (or if one opens a different tray and clicks on a link within it), the correct “aggregation” will appear in the right-hand-side tree view.

So in effect, what needs to be done is to modify the clone component

so that the same thing happens as in (ii) above when any of the

trays and links above are selected, e.g. the custom tray

and the custom link

.

As is always the case, the only way to figure out how to do this is to:

iii) set-up for external session debugging by strategically placing breakpoints within the code that executes when a link is selected from the left-hand-side tray view of the SAP-delivered component

;

iv) run this component and let the break-points tell you what the code does;

v) be very,

patient.

If one is diligent about doing (iii-v), one will learn in a matter of an hour or so what’s already been mentioned in earlier posts within this series:

a) When a link is clicked in the left-hand tray view, the method

of the

view of

is invoked;

b) this method invokes the method

of the SAP-delivered class

(since this is the class that has been declared as the handler of the

view of

);

c) this method invokes the

method of

;

d) this method invokes the

method of the SAP-delivered class

(because

has been set to this class – see earlier posts.)

e) this method invokes the

method of

;

and

:

f)

: the create_settings method of

contains the code that displays the correct tree-root node at the top of the right-hand-side tree-view (i.e. “Button”, or “Tree”, or “Table”, etc., depending on what left-hand-side tray link has been selected.)

In particular, the code in

that does this is:

*********************************************************************

•   create an instance of the new view element

    concatenate ‘NEW_’ (method_name)

      parameter-table

        lt_method_params.

•   add it to the hierarchy tree

    m_hier_tree_context_element = m_hier_tree_context_node->create_element( ).

    m_hier_tree_context_node->bind_element( new_item = m_hier_tree_context_element set_initial_elements = abap_false ).

    m_hier_tree_context_element->set_attribute( name = ‘EXPANDED’     value = abap_false ).

    m_hier_tree_context_element->set_attribute( name = ‘HAS_CHILDREN’ value = abap_false ).

    m_hier_tree_context_element->set_attribute( name = ‘TEXT’         value = set_attribute( name = ‘ICON’         value = icon ).

**************************************************************************

And therefore, all we have to do to achieve our objective is to modify the above code as follows:

****************************************************************************

•   create an instance of the new view element

•   add it to the hierarchy tree

    m_hier_tree_context_element = m_hier_tree_context_node->create_element( ).

    m_hier_tree_context_node->bind_element( new_item = m_hier_tree_context_element set_initial_elements = abap_false ).

    m_hier_tree_context_element->set_attribute( name = ‘EXPANDED’     value = abap_false ).

    m_hier_tree_context_element->set_attribute( name = ‘HAS_CHILDREN’ value = abap_false ).

    m_hier_tree_context_element->set_attribute( name = ‘TEXT’         value =