Error dump after using requestFocus()

Question

Hello!
I try to use the requestFocus method in my wd prog but I get a dump like:
Error stacktrace:
java.lang.NullPointerException
     at sap.com.telia.inputview.InputView.wdDoModifyView(InputView.java:138)
     at sap.com.telia.inputview.wdp.InternalInputView.wdDoModifyView(InternalInputView.java:405)
     at com.sap.tc.webdynpro.progmodel.generation.DelegatingView.doModifyView(DelegatingView.java:78)
     at com.sap.tc.webdynpro.progmodel.view.View.modifyView(View.java:190)
     at com.sap.tc.webdynpro.clientserver.cal.ClientComponent.doModifyView(ClientComponent.java:397)
     at com.sap.tc.webdynpro.clientserver.cal.ClientApplication.modifyView(ClientApplication.java:613)
     at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.handleActionEvent(WebDynproMainTask.java:372)
     at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.execute(WebDynproMainTask.java:640)
     at com.sap.tc.webdynpro.clientserver.cal.AbstractClient.executeTasks(AbstractClient.java:59)
     at com.sap.tc.webdynpro.clientserver.cal.ClientManager.doProcessing(ClientManager.java:251)
     at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doWebDynproProcessing(DispatcherServlet.java:154)
     at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doContent(DispatcherServlet.java:116)
     at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doGet(DispatcherServlet.java:48)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.runServlet(HttpHandlerImpl.java:391)
     at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.handleRequest(HttpHandlerImpl.java:265)
     at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:345)
     at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:323)
     at com.sap.engine.services.httpserver.server.RequestAnalizer.invokeWebContainer(RequestAnalizer.java:865)
     at com.sap.engine.services.httpserver.server.RequestAnalizer.handle(RequestAnalizer.java:240)
     at com.sap.engine.services.httpserver.server.Client.handle(Client.java:92)
     at com.sap.engine.services.httpserver.server.Processor.request(Processor.java:148)
     at com.sap.engine.core.service630.context.cluster.session.ApplicationSessionMessageListener.process(ApplicationSessionMessageListener.java:37)
     at com.sap.engine.core.cluster.impl6.session.UnorderedChannel$MessageRunner.run(UnorderedChannel.java:71)
     at com.sap.engine.core.thread.impl3.ActionObject.run(ActionObject.java:37)
     at java.security.AccessController.doPrivileged(Native Method)
     at com.sap.engine.core.thread.impl3.SingleThread.execute(SingleThread.java:94)
     at com.sap.engine.core.thread.impl3.SingleThread.run(SingleThread.java:162)
This is my code in wdDoModifyView:
  public static void wdDoModifyView(IPrivateInputView wdThis, IPrivateInputView.IContextNode wdContext, com.sap.tc.webdynpro.progmodel.api.IWDView view, boolean firstTime)
    //@@begin wdDoModifyView
     if(firstTime) {
          IWDInputField input = (IWDInputField)view.getElement("CustomerID");
          input.requestFocus();
    //@@end
CustomerID is not in a separate node, it's a value directly under rootnode.
I have CustomerID set as a String, is that a problem?. I just want focus to be on this field when the program starts.
I have a separate method for getting data (I know...it's a ugly hack but I'm a n00b and in the learningphase :
  //@@begin javadoc:onActionretrieveData(ServerEvent)
  /** Declared validating event handler. */
  //@@end
  public void onActionretrieveData(com.sap.tc.webdynpro.progmodel.api.IWDCustomEvent wdEvent )
    //@@begin onActionretrieveData(ServerEvent)
     String firstCustomerId = "1234";
     String secondCustomerId = "501025";
     String usedCustomerId = wdContext.currentContextElement().getCustomerID();
     if((usedCustomerId.equals(firstCustomerId)) || (usedCustomerId.equals(secondCustomerId))) {
          wdThis.wdGetTeliaPortalDemoCompController().Clear();
          wdThis.wdGetTeliaPortalDemoCompController().fillView();
     } else wdThis.wdGetTeliaPortalDemoCompController().Clear();
    //@@end

Answer 1

Instead of using IWDViewElement.requestFocus(), you could also use the "indirect" way
IWDViewController.requestFocus(IWDNodeElement nodeElement, IWDAttributeInfo attribute)
This method requests focus for the given context attribute  in your case the attribute to which the "value" property of the InputField is bound.
Armin