Shiny Action button not triggering observeEvent

Question

I'm trying to create a simple shiny app that asks two questions in a sequence. I created a div for each question, with the second one hidden. I am trying to use observeEvent with an action button to trigger a hide for the first div and a show for the second div upon click. However, clicking on the action button is not triggering the observeEvent. Any thoughts on where I'm missing something?

My ui.R is:

library(shiny)
library(shinyjs)


shinyUI(fluidPage(useShinyjs(),

  # Application title
  titlePanel("My Survey App"),

  # Sidebar with a slider input for number of bins
  sidebarLayout(
    sidebarPanel(

    ),

    # Show a plot of the generated distribution
    mainPanel(
      h2("survey"),
      wellPanel(
          h6('Placeholder for Placeholder for question'),
          br(),
          div(id = 'questionseq1div',
              h5('Text Question Here',align = 'center'),
              br(),br(),
              textInput('sequence-question-1', '', value = "", width = '100%', 
                        placeholder = 'Give a detailed explanation of your position on the question.'),
              br(),br(),
              fluidRow(
                column(6, align="center", offset = 3,
                       actionButton(inputId = 'completedquestion1',label = 'Next '),
                       tags$style(type='text/css', "#button { vertical-align: middle; height: 50px; width: 100%; font-size: 30px;}")
                )
              )
          ),
          shinyjs::hidden(div(id = 'questionseq2div',
                              h5('Slider Input Question Here',align = 'center'),
                              br(),br(),
                              sliderInput('sequence-question-2','Min: 1  Max: 5',min = 1,max = 5,step = 1,ticks = T,value = 3),
                              br(),br(),
                              fluidRow(
                                column(6, align="center", offset = 3,
                                       submitButton('completed-question-2','Submit '),
                                       tags$style(type='text/css', "#button { vertical-align: middle; height: 50px; width: 100%; font-size: 30px;}")
                                )
                              )
          )))
    )
  )
))

And my server.R is:

library(shiny)
library(shinyjs)

shinyServer(function(input, output,session) {

  observeEvent(input$completedquestion1,{
    print('Triggered')
    shinyjs::show('questionseq2div')
    shinyjs::hide('questionseq1div')

  })

})

Answer 1

I had to re-structure things to get it to work - I didn't see how you could get it to toggle back and forth without a question list to iterate though. And once that was there, then I added a few obvious things because it was kind of fun...

Anywhere here is a basic structure to do what you want.

library(shiny)
library(shinyjs)


qlist <- list(
"q1" = list(type="qtext","text"="first text question"), 
"q2" = list(type="qslid","text"="first slider question"), 
"q3" = list(type="qslid","text"="second slider question"), 
"q4" = list(type="qtext","text"="second text question")
)
u <- shinyUI(fluidPage(useShinyjs(),

  # Application title
  titlePanel("My Survey App"),

  sidebarLayout(
    sidebarPanel(  ),

    mainPanel(
       h2("survey"),
       wellPanel( h6(textOutput("curstatus")), 
                  br(),
                  h4(textOutput("curquestion")), 
       div(id = 'questionseq1div',
           h5('div1 - Text Div',align = 'center'), 
           br(),br(),
           textInput('sequence-question-1', '', value = "", width = '100%', 
                     placeholder = 'Give a detailed explanation of your position on the question.'), 
            br(),br()
        ),
        div(id = 'questionseq2div',
               h5('div2 - Slider Div',align = 'center'),
               br(),br(),
               sliderInput('sequence-question-2','Min: 1  Max: 5',min = 1,max = 5,step = 1,ticks = T,value = 3),
               br(),br()
         )
        ),
        div(id='nextbuttondiv',fluidRow(
          column(6, align="center", offset = 3,
                 actionButton(inputId = 'completedquestion',label = 'Next '),
                 tags$style(type='text/css', "#button { vertical-align: middle; height: 50px; width: 100%; font-size: 30px;}")
            )
           )
        )

))))
s <- shinyServer(function(input, output,session) {

       rv <- reactiveValues(qlist=qlist,curqnum=1,inited=FALSE,finished=FALSE)

       setupForCurQuestion <- function(){
         qcur <- rv$qlist[[rv$curqnum]]

         if (qcur$type=="qtext"){
           shinyjs::show('questionseq1div')
           shinyjs::hide('questionseq2div')
         } else {
           shinyjs::hide('questionseq1div')
           shinyjs::show('questionseq2div')
         }
       }

       advanceQuestionAndCheckFinish <- function(){
         if (rv$curqnum==length(rv$qlist)) return(TRUE)
         rv$curqnum <- rv$curqnum+1
         print(rv$curqnum)
         setupForCurQuestion()
         return(FALSE)
       }

       isolate(setupForCurQuestion()) 

       observeEvent(input$completedquestion,{
         if (!rv$finished){
           rv$finished <- advanceQuestionAndCheckFinish()
           if (rv$finished){
             shinyjs::hide('nextbuttondiv')
           }
         }
      })
      output$curquestion <- renderText({
        qcur <- rv$qlist[[rv$curqnum]]
        qcur$text
      })
      output$curstatus <- renderText({
        if (rv$finished) return("Finished")
        sprintf("Question %d of %d",rv$curqnum,length(rv$qlist))
      })
})
shinyApp(u,s)

Here is a screen shot: