SAP ABAP Webdynpro Interview Questions and Answers

1)   Types of ABAP UI Technologies

      Ans: Webdynpro for ABAP, BSP

2)   MVC Architecture Concepts and usage of the same in ABAP Webdynpro

      Ans: As per the MVC Architecture there is a clear separation between flow logic, view and the Business

              Logic. View holds all the UI elements that are visible in the UI, Controllers have the flow logic.

              Controllers are of different kind (Component Controller, View Conroller,Window Controller).

              Business logic is held in the Model which is in the form of Assistance class

              in webdynpro context.  

3)   Difference Between the View Container and the Transparent Container

      Ans: View Container holds the views, there can be multiple views assigned to the view container but only

      one view can be active(viewed) at a time. Transparent holds the webdynpro UI elements, A layout type

      can be associated  with it.

4)   What does a Model Class Consists of

      Ans: Model Class is the Assitance class in webdynpro. It contains the Business logic in the form of

      methods, Global data & Constants in the form of Class Attributes. The Model class can be accessed in

      webdynpro component using the attribute wd_assist->. Note: All the visibility properties of the

      Class are applicable when accessing the class using the object wd_assist.

5)   What is an Assistance Class and How is it Instantiated in Webdynpro

       Ans: Assistance Class is the model class which would act as the data provider  for the webdynpro

       component and it is instantiated by the webdynpro component during the run time and no explicat

       instantation is required.

6)   Design Patterns in Webdynpro(GAF,OIF,QAF Etc)

      Refer to the link:

      FPM Concepts in Webdynpro

7)   How do you debug an web based Application

      (Could be from ABAP Webdynpro, BSP or CRM Web UI)

       Ans: External break-points should be used to debug web UI's.

8)   How do you create a ALV Report/Editable ALV in Webdynpro

      Ans: ->Add the Standard ALV component to the web dynpro Component.

              ->Use Components tab: Ex: ALV_MATS  type SLV_WD_TABLE

              ->Create a context node with the table field information to be displayed

              ->Write the ALV Default Code for table display

              ->Set the read only attribute to false to switch to editable mode using

                 the method set_read_only of the interface

                IF_SALV_WD_TABLE_SETTINGS implementing class

                CL_SALV_WD_CONFIG_TABLE).

9)   How do you Navigate between Views in Webdynpro

       Ans: Navigation between Views is through Plugs(Inbound and Outbound),

10) Usage of Plugs in Webdynpro

       Ans: Plugs are used to Navigate between the views. Parameters can be passed using the plugs similar to

       interface parameters of function module or a class method.

11) Usage of Webdynpro Component Controller

       Ans: Component controller is used to the store the Global attributes and Methods of the component.

       Attributes/methods declared in the component controller are visible through out the component and they

       are accessed using the attribute wd_comp_controller outside of component  controller(like

       views,windows etc) All the context nodes defined in the component controller are

       visible in all the views and windows of the component.

       Ex: if a variable called gv_count is defined in the component controller, it can be accessed in the view

       using the syntax wd_comp_controller->gv_count.

12) How do you access a Context Nodes and elements Programmatically

      Code required for accessing the Context Nodes can be written using the webdynpro code wizard.

      For Ex: if there exists a Node Node1 with cardinality 1:1 and has 3 Attributes to it Att1, Att2,Att3. The

      attributes can be accessed using the below code.

      data: lo_nd_node1 type ref to if_wd_context_node.

      data: lo_el_node1 type ref to if_wd_context_element.

      data: ls_node1 type wd_this->element_node1.

      lo_nd_node1 = wd_context->get_child_node

      ( name = wd_this->wdctx_node1 ).

      lo_el_node1 = lo_nd_node1->get_element( ).

**Read Node1

      lo_el_node1->get_static_attributes(

          importing

          static_attributes = ls_node1 ).

**Write to Node1

      lo_el_node1->set_static_attributes(

          exporting

          static_attributes = ls_node1 ).

13) Message Areas in Webdynpro

      Message areas are created in views to display messages (Error,Success,Warning,Info).

      WD allows to have multiple Message errors in a view but throws an error when the view is displayed.

      Use the code wizard to get code for raising error messages. Few of the message classes and methods

      are: Interface: if_wd_message_manager.

      methods: report_t100_message.(used to report message from the  message class)

14) Concept of OTR(Online Text Repository) and its Usage

      OTR's are similar to text elements in ABAP. OTR's are created for

      UI texts and texts can be maintained in multiple language.

      OTR's can be created using the transaction: SOTR_EDIT

15) Concept of Interface Views

       If the views of a different components are need to be used in a webdynpro component mark the view as

       interface view and use it in another component. It's similar to using a include in a program.  A Interface

       view of the component can be used in any no of components. this concept supports the reusuability of

       the views.

16) Sequence of Webdynpro Events:

      Ex: WDDOINIT,WDMODIFYVIEW,WDAFTERACTION,

      WDBEFOREACTION etc

       Sequence: WDDOINIT of the component controller,

                       WDDOINIT of the Window Controller,

                       WDDOINIT of the View Controller,

      WDMODIFYVIEW(On Input/Display on any UI Element).

      WDBEFOREACTION(Method for validation of user input,

      Once the user action happens on the UI)

      WDAFTERACTION(Method for non-action specific operations

       before Navigation)

      WDDOEXIT( Exit from the View/Window/Component Controller)

      WDPOSTPROCESSING(used to perform exception handling for supply function methods)

17) Can a Component have Multiple Applications

       Yes, For a given webdynpro component any no of applications can be  created. Applications are similar

       to transactions in SAP.  You can associate different Interface views of the component to create different

       applications using the same component.

18) How do you launch a Webdynpro Application from a Transaction

      Refer to the previous blog Calling webdynpro application from a Transaction

      URL: http://saplatest.blogspot.in/2016/04/call-abap-webdynpro-application-from-r3_15.html

19) How do you Navigate between two Webdynpro Components

      You can use Interface views to navigate between components or create a navigation class and

      do a explicit call.

20) Creating a tree in Webdynpro

      Tree UI element is used to create Tree  in Webdynpro. Tree can be defined as part of the table column.

21) Usage of Exit Plug in a Webdynpro Window

      Exit plugs are outbound plugs used to close the webdynpro application.  they can be called from the view

      which are embedded in the window  Note: Exit plugs won't work in portal environment.

      Exit plugs can also be used to pass the call to another URL. Here is the sample code snippet of the exit

      plug call:

      method onexit .

        data url type string.

        data close_window type wdy_boolean.

        url = 'url_name'.

        close_window = abap_false.

        wd_this->fire_to_exit_plg( url = url

                                                 close_window = close_window ).

      endmethod.

22) why FQDN(Frequently Qualified Domain Name) is necessary for running Webdynpro Applications

      Refer to sap help:

      http://help.sap.com/saphelp_erp2005/helpdata/en/67/be9442572e1231e10000000a1550b0/content.htm

21) Standard ALV Component required to create ALV Reports in Webydnpro

      SALV_WD_TABLE

22) How do you build Select Options in Webdynpro

      Using the standard webdynpro component WDR_SELECT_OPTIONS

      You can refer to the example: WDR_TEST_SELECT_OPTIONS

23) How do you build F4 Search Help in Webdynpro

      A F4 help for an input field can be made available by attaching the search help

      to the table field. Usage of standard help component WDR_OVR.

      Creating a component for help and attaching it to the node element as Freely programmed value help

24) How are Plugs(Inbound/Outbound) bounded in the Window

      Plugs are created in the view and bounded in the window by using the drag drop option in the window

      view.

25) How do you Control the visibility of the Webdynpro UI elements Programmatically.

      Create a context element of type wdui_visibility and bind to the visibility property of the UI element.

26) What is the use of Interface views/nodes in Webdynpro.

       Interfaces nodes and views are created to use them in other webdynpro components.

27) How do you navigate between different Webdynpro applications

      Create a navigation class and trigger the target application to be called.

28) What are the webdynpro init  events and what is the sequence of trigger

       Sequence: WDDOINIT of the component controller,

                       WDDOINIT of the Window Controller,

                       WDDOINIT of the View Controller,

29) How are Error messages created and handled in webdynpro

      Create a message UI element in the view and trigger the message required(Error,warning,status) using the

      code generation wizard.

30) What is an OTR and mention its usage in Webdynpro

       Online Text Repository is the central storage for texts for webdynpro

       applications. An otr can be fetched in the program using the below mentioned code.

       data: lv_string type string.

        lv_string = cl_wd_utilities=>get_otr_text_by_alias(  alias =    

              'PACKAGE/OTR_NAME' ).

31) Can text elements be used in webdynpro, if yes how?

       Yes text elements can be used in webdynpro.

       Refer to the below code snippet.

        data: lv_string type string.

        lv_string = wd_assist->if_wd_component_assistance~get_text(  '025' ).    

32) What is the use of Road Map UI element

       Roadmap UI element is used to display step-by-step workflows. It can used to clearly define a process.

33) What are exit plugs?How are they created?

      Exit plugs are used to exit from the webdynpro page or an webdynpro window.

      Exit plugs are created in the window.

34) Is it possible to hide F4 function for an Input element programmatically?

      Yes it is possible to hide F4 function attached to an input field.Use the interface

      if_wd_context_node_info and the method set_attribute_value_help

35) How do Webydnpro Upload and download functions work, Explain.

      Fileupload UI element is used upload files from desktop the application.

      There is also restriction on the max data volumes that can be uploaded.

      Filedownload UI element is used to download files to the client.

36) Explain the concept of Road Map UI element in Webdynpro.

      Refer to the link: Road map UI element webdynpro for abap

37) How to create popups in webdynpro.

      Create a view and embed the view in the window and call the window to trigger the popup.

38) Explain the concept of OVS and its usage

      WDR_OVS is the standard webdynpro component to generate F4 helps

      for the input field. OVS refers to Object value selector.

39) Using Radio Buttons/Checkboxes/Dropdown lists in webdynpro

      Radio buttons/Checkboxes are used for objective selection similar to what is available in SAP GUI. An

      event is associated with each UI element for onclick action.

40) FPM Concept and its usage in webdynpro.->>>>Refer to the link

41) what is internationalization in webdynpro abap application?

      Internalization refers to creation of texts used in webdynpro application in a specific language and

      providing option to translate to multiple languages if necessary. This is achieved by using OTR's or text

      elements for static texts and performing translation when required.

42) What is Cardinality of a context node in webdynpro

       Cardinality refers to no of elements a node can accomodate during run time. When a node is created the

       cardinality is assigned to it. Cardinality is of the following kinds:

       0:1 -->At run time, no element or maximum one element can be instantiated

       0:n -->At run time, no element or maximum of n elements can be instantiated

       1:n -->At run time, minimum one element or maximum of n elements can be instantiated

       1:1 -->At run time, only one element should always be instantiated

       if you try violating the cardinality there would be a short dump saying Number of elements of the

       collection of node node_name violates the cardinality

 43) what is Personalization in abap webdynpro application

        Personalization refers to changing the properities of UI elements at runtime. Personalization settings are

        user specific. Configuration controller is used for personalization function.

        ex: Changing the order of columns in a table display.

 44) what are the controller types in webdynpro ABAP

        -Component Controller->Component Controller is global part of the component and each component

          has only one component controller. Global Attributes and  methods required by the component can be

          defined here.

        -Custom Controllers->Custom controllers are defined during design time and  these are optional. The

          visibility Custom controllers is in the entire component and has the life time equal to life time of the

          component. Custom controllers are used if a set of views have to be grouped to perform

          a special function or hold a set of data.

         -View Controller->Flow logic of the views are in view controller and a view can  have only one view

           controller. The visibility of View controller is specific to view only.

         -Configuration Controller->Configuration controller is used achieve personalization function.

         -Window Controller->A window controller exists for each window and can also have methods

           to write coding logic. Every window will have the default method and it is used to  receive

           parameters. The windows controllers are visible in entire component and also in the custom        

           controller.

45)what are Layout types in Webdynpro and its usage

         ->Flow Layout  : Used for sequential display of WD UI elements.

         ->Row Layout  : here each ui element is displayed on its own column and the width differs from row to

             row.Rowheaddata is used to insert a break.

         ->Grid Layout  : Ui elements are arranged based the no of columns. line breaks  are inserted based on

             the size.

         ->Matrix Layout: Matrix layout arranges ui elements in columns. Matrixheaddata is used to insert a line

            break.

            Usage of the appropriate layout to build a webdynpro application is determined during the UI

            design.

 46)what is supply function method in SAP

         ->Supply function method is used to populate the context node or to default values to the context

             node elements. supply function method is called before the node is accessed for first read.

         ->Using supply function method is optional

47)what is singleton property of context node

         ->Singleton property is one of the attributes of the context node if this is set there can be only one

             instance of the respective context node at runtime.

48)How to default a value to the context attribute

     In the context attribute there is a property to set the default value. Use the same, However the

     default value can be overwritten using the set_attribute method of the interface if_wd_context_element.