SAP WebDynPro Interview Questions and Answers

Web Dynpro is standard SAP UI technology that allows you to develop web applications using graphical tools and development environment integrated with ABAP workbench. Using graphical tools reduce the implementation effort and you can better reuse and maintain components in ABAP workbench.

These are key benefits of using Web Dynpro for developers in ABAP environment −

• You can easily maintain and reuse components for development.
• Less implementation time as use of graphical tools.
• You can easily change layout and navigation using graphical tools.
• Easy structure changes.
• With use of data binding, you can use automatic data transport.
• Ease of integration in ABAP environment.
• Web Dynpro ABAP is same as Web Dynpro Java as support same set of functions for the application development.

Web Dynpro applications are based on MVC model, whereas −

Model

This allows the access to back end data in a Web Dynpro application.

View

This is used to ensure the representation of data in a web browser.

Controller

This is used to control communication between Model and view where it takes input from users and get the processes data from model and displays the data in browser.

Each Web Dynpro application contains at least one view and it is used to define layout of a user interface. Each view consists of multiple user element and a controller and context.

The controller is used to process user request and processing of data and context contains data to which elements of view are bound.

You can navigate between different views using inbound and outbound plugs. The inbound and outbound plugs are part of view controller and inbound plug defines the starting point of view and outbound plug tells the subsequent view to be called.

A view set is defined as predefined section where you can embed different views in a Web Dynpro application. View set allows you to display more than one view in a screen.

Below are few advantages of view set in designing an application −

• You can reuse views in a Web Dynpro window.
• You can easily make changes to layout at later stage.
• More structured approach to use more than one view.

In Web Dynpro, window is used to use multiple views or view sets. A view can only be displayed when it is embedded in a view and a window always contain one or more views which are connected by navigation links.

Each window contains inbound and outbound plugs and they can be included in navigation chain. Inbound plugs within a window lead from the outbound plug of a view to the embedding window. Just like all other inbound plugs, they represent an event and thus call the event handler assigned to them.

Controllers are used to define how a Dynpro application responds to user interactions. Each view has one controller which is responsible to perform actions as per user interaction.

In Dynpro application, you can define mapping between two global controller contexts or from view context to global controller context.

Data binding of a UI element property is set up in the view layout. For this purpose, you use the Binding column in the properties table of the embedded UI elements. You click the button to open a dialog box which provides the context structure of the corresponding view for an element selection.

You can create events to enable communication between controllers. You can allow one controller to trigger events in different controller. All events that you create in component controller they are available in component.

In Global controller, the data declared in this can be accessed by all views and window in that component.

View controller is a local controller for that view and can’t be accessed by other controllers.

Whenever we want views, nodes or methods of a particular web dynpro component to be available to other the outside world (i.e. other webdynpro components) , we make use of Interface controller . Interface Controller is created by default when a webdynpro component is created.

Interface Controller would generally come into picture when you are doing component usage of some sort in web dynpro i.e. re-using views/methods/nodes of one WD component in another.

When your Component Controller grows big in size (say more than 10-15 views and corresponding context nodes, methods, events, event handlers etc) , it might become tough to handle everything in the Component Controller . In such a scenario, you can create one or more custom controllers and modularize or segregate the logic into separate parts using Custom Controller.

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.

Faceless components in Web Dynpro doesn’t contain any graphical components, no views or no windows. It only contains a component controller and you can add an additional custom controller.

Faceless components are specifically used for receiving and structuring the data. Faceless components can be embedded to other components using component usage and you can supply the required data to these components.

You can use version management to manage older version of an object, compare versions or you can also reset them.

Component Controller is only one. You can create multiple controllers, but those are called Custom Controllers.

If the node is going to be accessed in multiple views, it should be declared at the Component Controller level. However, If the node is absolutely specific to only one view, it can be defined in the View Controller.

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. Matrix headdata is used to insert a line break. Usage of the appropriate layout to build a webdynpro application is determined during the UI design.

A Model class is assistance class that contains business logic.

Using External breakpoints

Using inbound and outbound plugs

Yes, for a component, you can create any number of applications.

In a Web Dynpro application, component window has an inbound plug. This inbound plug can have parameters, which have to be specified as URL parameters.

Default values that are overwritten by the URL parameters can be set in the application for these parameters. If neither a default value nor a URL parameter is specified, a runtime error is triggered.

Using method _WD_COMPONENT_ASSISTANCE~GET_TEXT( ), this allows you to access text symbols of the assistance class in controller of your component.

It is suggested to set the breakpoint in method WDDOMODIFYVIEW under METHODS tab of Dynpro view.

In ABAP Workbench, you can also create and show messages that contain information for end users of Dynpro application. These messages are displayed on the screen. These are user interactive messages that displays important information about Web Dynpro application.

You can create forms based on Adobe software and can use in context for Web Dynpro user interfaces. You can integrate Adobe lifecycle development tool with ABAP editor to ease the development of user interface. Interactive forms using Adobe software allows you to create efficiently and easy development of UI elements.

• Interactive Scenario
• Print Scenario
• Offline Scenario
• Using digital signature

SAP List viewer is used to add ALV component and provides a flexible environment to display lists and tabular structure. A standard output consist of header, tool bar and an output table and user can make the settings to add column display, aggregations, sorting options using additional dialog boxes.

• It supports many properties of table element as it is based on Web Dynpro table UI element.
• ALV output can be filtered, sorted or you can also apply calculations.
• User can perform application specific functions using UI elements in toolbar.
• This allows user to save setting in different views.
• You can also configure special areas above and below ALV output.
• You can define extent to which ALV output can be edited.

Using filters, you can limit the data in ALV output. You can create multiple number of filter conditions for each field. To create or delete a filter condition, you can use method of interface class IF_SALV_WD_FILTER.

In Web Dynpro ABAP administration, you can perform various administration tasks using different tools −

• ICM Tracing
• Web Dynpro Trace tool
• Browser Tracing
• Logging
• Security

To trace the data stream in SAP Web Application server.

You can monitor Web Dynpro application using ABAP monitor. Information is stored about Web Dynpro application and is stored. You can view this information using T-code: RZ20

• Session Count
• Application Count
• CPU time
• Data

To use in other Web Dynpro components.

• WDDOINIT of component Controller
• WDDOINIT of window Controller
• WDDOINIT of View Controller

It is used to create text is specific language and to provide translation in multiple languages in Web Dynpro application.

• Component Controller
• Custom Controller
• Configuration Controller
• View Controller
• Window Controller