R Shiny 中的 renderUI 不显示

Question

Sometimes we'd like to put content in a uiOutput/renderUI. But this doesn't always work. For instance, the example below. In my mind, code#1 and code#2 should give me the same GUI. However, code#2 doesn't work as expected. Can anyone tell me the reason? Thanks!

Code#1:

library(shiny)

ui <- navbarPage("test",
                 navbarMenu("More",
                            tabPanel("Table"
                            )
                 )
)

server <- shinyServer(function(input, output, session) {
})

shinyApp(ui = ui, server = server)

Code#2:

library(shiny)

ui <- navbarPage("test",
           uiOutput("ui_data")
)

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

  output$ui_data <- renderUI({
    navbarMenu("More",
               tabPanel("Table"
               )
    )
  })

})

shinyApp(ui = ui, server = server)

Answer 1

In the second example, uiOutput wraps the content of navbarMenu inside a div with the class "shiny-html-output" . Divs of this class are however not allowed as an argument for navbarPage . AFAIK, there are two ways to resolve this

The first is to create the whole navbarPage on the server-side.

library(shiny)

ui <- uiOutput("page")

server <- shinyServer(function(input, output, session) {
  output$page <- renderUI({
    navbarPage("test", navbarMenu("More", tabPanel("Table")))
  })
})

shinyApp(ui, server)

The other one is to only create the contents of the tabPanel in the server

library(shiny)

ui <- navbarPage(
  "test", 
  navbarMenu("More", tabPanel("Table", uiOutput("tab_content")))
)

server <- shinyServer(function(input, output, session) {
  output$tab_content <- renderUI({
    "Some content"
  })
})

shinyApp(ui = ui, server = server)

Answer 2

Please try to set your working directory first like example below.

setwd("c:/Users/ID/Desktop/folder")

You should get working directory with location of ui.R and server.R.