displaying busy indicator on primefaces wizard component

 Using primefaces 8 to build a java web application, I had trouble figuring out how to display a busy indicator from a primefaces wizard component.  Other views use onstart/oncomplete attributes for button actions to display a "loading dialog" that indicates the application is busy while the action completes.  That approach doesn't work for wizard navigation, because the action is performed asynchronously from the button click.  I found a stack overflow thread with a description of the solution.

In a nutshell, I used the "onnext" attribute of the p:wizard tag to open the busy dialog, and the flowListener method (onFlowProcess()) to close it.  Here are a couple of code snippets.

First the xhtml code for the wizard:

        <p:wizard id="importWizard"
                  flowListener="#{wizardController.onFlowProcess}" 
                  widgetVar="#{rootViewId}"
                  showStepStatus="false" 
                  showNavBar="false"
                  onnext="PF('loadingDialog').show();">

The code for the modal loading dialog:

    <p:dialog modal="true" 
              id="loadingDialog"
              widgetVar="loadingDialog" 
              showHeader="false" 
              styleClass="viewTransparentBackgroundDialog"
              resizable="false">
        <h:outputText value="Loading Results... Please Wait..." />
        <p/>
        <p:graphicImage library="images" name="ajax-loader.gif" />
    </p:dialog>

The java server code:

     public String onFlowProcess(FlowEvent event) {
        String result = onFlowProcessHandler(event);
        SessionUtility.executeRemoteCommand("PF('loadingDialog').hide();");
        return result;
    }