UI

#| standalone: true
#| components: [viewer]
#| viewerHeight: 300

library(shiny)
library(bslib)

ui <- page_fluid(
  checkboxInput("show_slider", label = "Show slider", value = TRUE),
  uiOutput("slider_ui") 
)

server <- function(input, output) {
  output$slider_ui <- renderUI({ 
    if (input$show_slider) { 
      sliderInput("slider", "Slider", 1, 10, 5) 
    } 
  }) 
}

shinyApp(ui = ui, server = server)
library(shiny)
library(bslib)

ui <- page_fluid(
  checkboxInput("show_slider", label = "Show slider", value = TRUE),
  uiOutput("slider_ui") 
)

server <- function(input, output) {
  output$slider_ui <- renderUI({ 
    if (input$show_slider) { 
      sliderInput("slider", "Slider", 1, 10, 5) 
    } 
  }) 
}

shinyApp(ui = ui, server = server)
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Relevant Functions

  • uiOutput
    uiOutput(outputId, inline = FALSE, container = if (inline) span else div, fill = FALSE, ...)

  • renderUI
    renderUI(expr, env = parent.frame(), quoted = FALSE, outputArgs = list())

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Details

A UI output creates an output container for a UI (i.e., HTML) element, such as a set of additional controls. Adding a UI output allows you to show, hide, or update input controls within your app.

To add a UI output, follow three steps:

  1. Call uiOutput() in the UI of your app to create a div in which to display the UI element. Where you call this function within the UI functions will determine where the UI element will appear within the layout of the app. Set the outputId argument of uiOutput() to a unique value.

  2. Within the server function, call renderUI() and save its output as an element of the output list. Name the element after the outputId used above. For example, output$ui <- renderUI(). uiOutput() will display the value of the output element whose name matches its outputId.

  3. Pass renderUI() a block of code, surrounded with {}. The code should return a Shiny tag object, an object created with HTML(), or a list of such objects.

See also: Dynamic UI.

Variations

Create dependent controls

You can use renderUI() and uiOutput() to create a set of controls that are dependent on a setting in your app. In this example, we show a different set of options when the app is in “plot” or “table” mode. Note that we use the current input values or a default value when creating the dependent controls. Without this, the values are re-initialized every time and forget previous user input.

#| standalone: true
#| components: [viewer]
#| viewerHeight: 225

library(shiny)
library(bslib)

ui <- page_fluid(
  radioButtons(
    "mode",
    "Display mode",
    choices = c("Table", "Plot"),
    selected = "Table"
  ),
  uiOutput("mode_controls") 
)

server <- function(input, output) {
  output$mode_controls <- renderUI({ 
    if (input$mode == "Table") { 
      rows <- ifelse(!is.null(input$rows), input$rows, 10) 
      cols <- ifelse(!is.null(input$cols), input$cols, 4) 
      tagList( 
        sliderInput("rows", "Rows:", value = rows, min = 1, max = 10), 
        sliderInput("cols", "Columns:", value = cols, min = 1, max = 10) 
      ) 
    } 

    else { 
      height <- ifelse(!is.null(input$height), input$height, 500) 
      width <- ifelse(!is.null(input$width), input$width, 500) 
      tagList( 
        sliderInput("height", "Height:", value = height, min = 100, max = 1000), 
        sliderInput("width", "Width:", value = width, min = 100, max = 1000), 
      ) 
    } 
  }) 
}

shinyApp(ui = ui, server = server)

library(shiny)
library(bslib)

ui <- page_fluid(
  radioButtons(
    "mode",
    "Display mode",
    choices = c("Table", "Plot"),
    selected = "Table"
  ),
  uiOutput("mode_controls") 
)

server <- function(input, output) {
  output$mode_controls <- renderUI({ 
    if (input$mode == "Table") { 
      rows <- ifelse(!is.null(input$rows), input$rows, 10) 
      cols <- ifelse(!is.null(input$cols), input$cols, 4) 
      tagList( 
        sliderInput("rows", "Rows:", value = rows, min = 1, max = 10), 
        sliderInput("cols", "Columns:", value = cols, min = 1, max = 10) 
      ) 
    } 

    else { 
      height <- ifelse(!is.null(input$height), input$height, 500) 
      width <- ifelse(!is.null(input$width), input$width, 500) 
      tagList( 
        sliderInput("height", "Height:", value = height, min = 100, max = 1000), 
        sliderInput("width", "Width:", value = width, min = 100, max = 1000), 
      ) 
    } 
  }) 
}

shinyApp(ui = ui, server = server)
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