How to access values from dynamically generated UI elements that are not initially visible

Question

If you run this app 'a' the default selected value does not appear until the UI tab is selected and the UI element which populates 'input$select' is generated. How can I force this element to be created when the app is loaded without the need to click on the panel to initialize it in order to get access to its default value.

library(shiny)
library(shinydashboard)

ui <- fluidPage(
    tabsetPanel(
        tabPanel(
            title = "landing",
            "Stuff"
        ),
        tabPanel(
            title = "UI",
            uiOutput("select")
        )
    ),
    textOutput("out")
)

server <- function(input, output, session) {
    output$select <- renderUI(
        selectInput(
            "select", "Selector:", choices = c("a", "b"), selected = "a"
        )
    )
    
    output$out <- renderText(input$select)
}

shinyApp(ui, server)

starja · Accepted Answer · 2020-07-23 14:39:38Z

1

You can use the argument suspendWhenHidden = FALSE from outputOptions. I had to play a bit where to place outputOptions (it doesn't work at the beginning of the server function). However, it still needs a little bit of time to load, so maybe one could optimise it further.

library(shiny)
library(shinydashboard)

ui <- fluidPage(
  tabsetPanel(
    tabPanel(
      title = "landing",
      "Stuff"
    ),
    tabPanel(
      title = "UI",
      uiOutput("select")
    )
  ),
  textOutput("out")
)

server <- function(input, output, session) {
  
  output$select <- renderUI({
    selectInput(
      "select", "Selector:", choices = c("a", "b"), selected = "a"
    )
  })
  
  output$out <- renderText(input$select)
  outputOptions(output, "select", suspendWhenHidden = FALSE)
}

shinyApp(ui, server)

answered Jul 23, 2020 at 14:39

starja

10.5k1 gold badge17 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Richard J. Acton Over a year ago

I did not know about the outputOptions() function that seems to solve the problem in my actual use case as well as this toy example thanks!

Collectives™ on Stack Overflow

How to access values from dynamically generated UI elements that are not initially visible

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related