Calling FM in SAP

Question

I have a requirement wherein i need to pass a user input value to a FM created in ABAP.
Based on that i need to display the results or display a message if no results found.
Can any of the forum member supply me with the code/documentation which can help me achieve this?
I have already gone thru the basic webdnpro tutortial for calling rfc's.
Thanks in advance

Answer 1

Stride,
This online demo explains very clearly what you are looking for :
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/b017bd92-320d-2b10-81ae-ac921eff585d
Some More:
Already SDN friends provided some information , jsut i am trying to share some info and it might be helpful.
Step1: Once you know which function module your going to use , make sure that Funcation module is working in expected way. Ex: what are the input parameters you suppose to give , is returning the expected results are not? if there is no results found in the backend table what kind of error message it should throw?
These things you can perform while logging on to the SAP Backend System and use the TCODE : SE37 , enter the FM name and display. Once you open the required function module provide the expected input parameters and Execute it.
Now we expected to see the results if the data is avaialable if not you will see the appropriate error message or some other message based on the program developed.
Step2: From the NWDS Import the model while importing the model you required to provide the appropriate backend system details to call the RFC.
Step 3: Say example , when the user selects Results button on view then it should return the results in a table. The Results Button event calls the appropriate methos from the controller.
in View controller under Results action event you call the methos from the controller as below:
public void onActionResults(com.sap.xxx.webdynpro.progmodel.api.IWDCustomEvent wdEvent){
    //@@begin onActionResults(ServerEvent)
    wdThis.wdGetCOMPNAMEController().getRsults();
    //@@end
Step 4: Now in the component controller create a method called getresults() and execute your function module as below shown:
public void getResults{
//Initializing The RFC model class
Zs_results_volume_Input input = new Zs_results_volume_Input();
//if the RFC expect any manadatory parameters you have to set them before excuting the function module, normally most of the rfc'S expect input
parameters as Userid, Role, laungauge as input parameters.
// set user id which is retrived from the portal frame work in the runtime
input.setUser(WDClientUser.getCurrentUser().getSAPUser().getUserAccounts()[0].getLogonUid().toUpperCase());
//if you want to send launguage also as a mandatory parameter you can
input.setLanguage("EN");
//after settting the values bind the input object
wdContext.nodeAllowedValues().bind(input);
//if RFC execution is done from some different method
wdThis.executeZs_Results_Volume();
//implementation of the executeZs_Results_Volume() method:
public void executeZs_Results_Volume()
    //@@begin executeZs_Results_Volume()
     try
               // Calls remote function module Zs_results_volume_Input
               wdContext.currentZs_results_Volume_InputElement().modelObject().execute();
               // Synchronise the data in the context with the data in the model
               wdContext.nodeOuput_Results_Vol().invalidate();
          catch (Exception ex)
               // If an exception is thrown, then the stack trace will be printed
               wdComponentAPI.getMessageManager().reportException("Error while executing RFC: Zs_results_volume_Input Details : " + ex.getMessage(), true);
   //@@end
For mor help:
Creating a Web Dynpro Application Accessing ABAP Functions
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/355b9c90-0201-0010-d2a8-89fece426526
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/b017bd92-320d-2b10-81ae-ac921eff585d
http://help.sap.com/saphelp_nw04s/helpdata/en/15/0d4f21c17c8044af4868130e9fea07/frameset.htm
tps://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/e07753b9-fa0c-2a10-64a8-c6754c45396e