I am trying to create an action button whereby I select a set of input parameters via checkboxes and a slider and then upon clicking the action button I the data to be re-analysed in R and the graph to re-render to the page. My attempt is as follows:

uicell <- dashboardPage(
  dashboardHeader(title="TB Diagnostic Biomarkers"),
  dashboardSidebar(),
  dashboardBody(
    fluidRow(
      box(checkboxGroupInput("selections", label = "Select tagData", choices = colnames(GENES_TO_CONTRAST))
      ),
      box(sliderInput(inputId="num5", label="Choose par", value=0.3, min=0, max=0.7),
      actionButton(inputId="change", label="Update"), value=colnames(GENES_TO_CONTRAST)),
      box(plotOutput("SPV"))
    )
  )
)
servercell <- function(input, output) {
  EmapTag=tagData(GENES_TO_CONTRAST[, input$selections], 0.7, max=15, ref=E.rna2, ref.mean=F),
  dataInput<-eventReactive(input$change, {
    runif(input$change)
  }),
  output$SPV<-renderPlot({
    getAllSPVs(E.rna2, grp=outcome, dataTag=dataInput(), method="raw", plot=T, mix.par=input$num5)
  })
}
shinyApp(uicell, servercell)

Everything looks fine up until the error: "object output not found" after "output$SPV<-renderPlot({.....})"

Does anyone know how I might improve my code to get the graph to re-render upon resetting the input options and clicking the update button?

Hi Christopher,

There seem to be some syntactical problems with your server function. Unlike the UI functions `dashboardPage` or `fluidRow`, which take as arguments different elements to include within the page, the server part is defined as a regular function; as such you shouldn't include commas `,` after `EmapTag` and `dataInput` definitions.

Cheers,

Andrzej