Hi RAP Developers, Good Day
Introduction:
In the SAP RAP (RESTful ABAP Programming Model), enhancing UI behavior dynamically is a common requirement, especially when business rules demand that certain fields be shown or hidden based on the underlying data. While RAP provides powerful mechanisms for extending behavior, one of the most flexible techniques for achieving dynamic UI control is through virtual elements.
Solution Overview:
Virtual elements allow developers to calculate values at runtime without physically storing them in the database. Beyond computed fields, they can also serve as UI control flags, for example, determining whether a field should be visible, editable, or hidden in the Fiori Elements UI. In this blog, we explore how to leverage virtual elements to dynamically show or hide UI fields based on data conditions. Using a simple ABAP class implementation, we demonstrate how a virtual field can drive UI visibility logic efficiently within RAP.
Projection View:
@ObjectModel.virtualElementCalculatedBy: ‘ABAP:ZCL_HIDE_VIRT’
virtual ishide : abap_boolean
Metadata Extension:
” Hide field from Identification section based on virtual element ‘ishide’
.identification: [{ position: 40, hidden: #( ishide ) }]
” Display field in Line Item section
.lineItem: [{ position: 30 }]
” Make field available as a Selection Field
.selectionField: [{ position: 30 }]
” Business field – Total Price
TotalPrice;
Implement Virtual Elements:
CLASS zcl_hide_virt DEFINITION
PUBLIC
FINAL
CREATE PUBLIC .
PUBLIC SECTION.
” SADL Exit Interface
INTERFACES if_sadl_exit .
” Interface for Virtual Element Calculation (Read)
INTERFACES if_sadl_exit_calc_element_read .
PROTECTED SECTION.
PRIVATE SECTION.
ENDCLASS.
CLASS zcl_hide_virt IMPLEMENTATION.
METHOD if_sadl_exit_calc_element_read~calculate.
“——————————————————————
” Purpose: Populate virtual element ‘ishide’ based on TotalPrice
” to control field visibility in the UI.
“——————————————————————
DATA : lt_virtual TYPE TABLE OF zc_tbjrn.
” Copy original data to local internal table
lt_virtual = CORRESPONDING #( it_original_data ).
” Loop through internal table and set virtual element value
LOOP AT lt_virtual ASSIGNING FIELD-SYMBOL(<fs_travel>).
” Set ishide = abap_true when TotalPrice <= 142, else false
<fs_travel>-ishide = COND abap_boolean(
WHEN <fs_travel>-totalprice LE 142
THEN abap_true
ELSE abap_false ).
ENDLOOP.
” Return updated table with calculated virtual element
ct_calculated_data = CORRESPONDING #( lt_virtual ).
ENDMETHOD.
METHOD if_sadl_exit_calc_element_read~get_calculation_info.
” No additional calculation info required
ENDMETHOD.
ENDCLASS.
Preview:
Conclusion:
By leveraging virtual elements together with the SADL exit class, we can dynamically control field visibility in RAP applications without modifying the actual database layer. This approach provides a clean separation between data and UI logic, improves performance, and keeps the design fully extensible. With a simple calculation exit, fields like Hide Indicator can be determined at runtime based on business rules, allowing the UI to react instantly and display only what is relevant to the user. This method ensures a smarter, more flexible, and more maintainable RAP application.
Thanks For Reading My Blog..
Hi RAP Developers, Good DayIntroduction:In the SAP RAP (RESTful ABAP Programming Model), enhancing UI behavior dynamically is a common requirement, especially when business rules demand that certain fields be shown or hidden based on the underlying data. While RAP provides powerful mechanisms for extending behavior, one of the most flexible techniques for achieving dynamic UI control is through virtual elements.Solution Overview:Virtual elements allow developers to calculate values at runtime without physically storing them in the database. Beyond computed fields, they can also serve as UI control flags, for example, determining whether a field should be visible, editable, or hidden in the Fiori Elements UI. In this blog, we explore how to leverage virtual elements to dynamically show or hide UI fields based on data conditions. Using a simple ABAP class implementation, we demonstrate how a virtual field can drive UI visibility logic efficiently within RAP.Projection View:@ObjectModel.virtualElementCalculatedBy: ‘ABAP:ZCL_HIDE_VIRT’
virtual ishide : abap_booleanMetadata Extension: ” Hide field from Identification section based on virtual element ‘ishide’
.identification: [{ position: 40, hidden: #( ishide ) }]
” Display field in Line Item section
.lineItem: [{ position: 30 }]
” Make field available as a Selection Field
.selectionField: [{ position: 30 }]
” Business field – Total Price
TotalPrice;Implement Virtual Elements:CLASS zcl_hide_virt DEFINITION
PUBLIC
FINAL
CREATE PUBLIC .
PUBLIC SECTION.
” SADL Exit Interface
INTERFACES if_sadl_exit .
” Interface for Virtual Element Calculation (Read)
INTERFACES if_sadl_exit_calc_element_read .
PROTECTED SECTION.
PRIVATE SECTION.
ENDCLASS.
CLASS zcl_hide_virt IMPLEMENTATION.
METHOD if_sadl_exit_calc_element_read~calculate.
“——————————————————————
” Purpose: Populate virtual element ‘ishide’ based on TotalPrice
” to control field visibility in the UI.
“——————————————————————
DATA : lt_virtual TYPE TABLE OF zc_tbjrn.
” Copy original data to local internal table
lt_virtual = CORRESPONDING #( it_original_data ).
” Loop through internal table and set virtual element value
LOOP AT lt_virtual ASSIGNING FIELD-SYMBOL(<fs_travel>).
” Set ishide = abap_true when TotalPrice <= 142, else false
<fs_travel>-ishide = COND abap_boolean(
WHEN <fs_travel>-totalprice LE 142
THEN abap_true
ELSE abap_false ).
ENDLOOP.
” Return updated table with calculated virtual element
ct_calculated_data = CORRESPONDING #( lt_virtual ).
ENDMETHOD.
METHOD if_sadl_exit_calc_element_read~get_calculation_info.
” No additional calculation info required
ENDMETHOD.
ENDCLASS.Preview:Conclusion:By leveraging virtual elements together with the SADL exit class, we can dynamically control field visibility in RAP applications without modifying the actual database layer. This approach provides a clean separation between data and UI logic, improves performance, and keeps the design fully extensible. With a simple calculation exit, fields like Hide Indicator can be determined at runtime based on business rules, allowing the UI to react instantly and display only what is relevant to the user. This method ensures a smarter, more flexible, and more maintainable RAP application.Thanks For Reading My Blog.. Read More Technology Blog Posts by Members articles
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