How to use required parameter in rich text display field?

The Rich Text Display Field of course does not have a "required" parameter as it is, ostensibly, a read-only input.  The fact that we can use links and differing stying and icons and fun stuff like that, in order to essentially transform Rich Text into an ad-hoc input, doesn't actually override the fact that no data is being inputted into the field, meaning there's nothing as easy as "use required parameter" to force the user into said action.

The above responses will work, though (through only a quick glance) it looks like those ad-hoc validations will show up immediately and continue showing up until the value is entered, but also won't prevent a button click like a normal failed validation would.  This is where we can use a Section-level (or form-level) validation using a!validationMessage(), which has the unique ability to optionally be set to not evaluate its failure condition until Submit Click has been attempted by the user.

A portable example with local-only variables is attached:

a!localVariables(
  
  local!rating: tointeger(null()),
  local!totalStars: 7,
  
  
  a!sectionLayout(
    contents: {
      a!richTextDisplayField(
        /*showWhen: a!isNotNullOrEmpty(local!rating),*/
        label: "Rating",
        value: {
          a!forEach(
            items: enumerate(local!totalStars)+1,
            expression: {
              a!richTextIcon(
                size: "MEDIUM",
                icon: if(
                  or(fv!index > local!rating, a!isNullOrEmpty(local!rating)),
                  "star-o",
                  "star"
                ),
                link: a!dynamicLink(
                  saveInto: {
                    a!save(
                      local!rating,
                      if(fv!item = local!rating, tointeger(null()), fv!item)
                    )
                  }
                ),
                linkStyle: "STANDALONE"
              )
            }
          ),
          
          a!richTextItem(
            size: "SMALL",
            color: "NEGATIVE",
            text: {
              char(10),
              "(* Required)"
            }
          )
        }
      ),
      
      a!buttonArrayLayout(
        align: "CENTER",
        buttons: {
          a!buttonWidget(
            label: "SUBMIT",
            submit: true(),
            validate: true()
          )
        }
      )
    },
    
    validations: {
      a!validationMessage(
        message: "A rating is required.",
        showWhen: a!isNullOrEmpty(local!rating),
        validateAfter: "SUBMIT"
      )
    }
  )
)

Thank you Mike

Thank you Mike