How to use tabPanel as input in R Shiny?

Question

Is it possible to perform an action if the user clicks into a particular tabPanel?

For instance, if the user clicks into tabPanel("A", ...) then display a popup saying You are viewing tab "A".

Answer 1

tabsetPanel() will return the value assigned to the active tabPanel(). If you just want to update another output you could do something like this:

ui.R

library(shiny)    

shinyUI(basicPage( 

  textOutput("text"),
      tabsetPanel(id = "tabs",
          tabPanel("Tab A", value = "A", "This is Tab A content"),
          tabPanel("Tab B", value = "B", "Here's some content for tab B.")
  )

))

server.R

library(shiny)

shinyServer(function(input, output) {

    output$text <- renderText({paste0("You are viewing tab \"", input$tabs, "\"")})

})

but something more complicated like creating a popup would probably require making an observer and some additional custom coding...

Answer 2

If you are using shiny dashboard, input$tabBox_id will locate the active tab name. Refer to here: https://rstudio.github.io/shinydashboard/structure.html#tabbox