Highlight border or color of R shiny button when selected

Question

Does someone know how to highlight the border or the color of a shiny button when it is selected ?

Please find a reproductible example below

library(shiny)

ui <- fluidPage(
  actionButton(inputId = "button1", label = "Select red"),
  actionButton(inputId = "button2", label = "Select blue"),
  plotOutput("distPlot")
)


server <- function(input, output) {
    r <- reactiveValues(my_color = "green")

    output$distPlot <- renderPlot({
      x <- faithful[, 2]
      bins <- seq(min(x), max(x))
      hist(x, breaks = bins, col = r$my_color)
    })

   observeEvent(input$button1, {
      r$my_color <- "red"
    })

  observeEvent(input$button2, {
    r$my_color <- "blue"
   })
}

shinyApp(ui = ui, server = server)

Here is what it get with the code above:

And here is what I would like to get when the button "Select red" is beeing selected (please note that it should highlight the other one when selected) :

If that is not possible, does exist a way to change button color when selected ?

Thanks in advance

Answer 1

You can add/remove CSS classes on the buttons using the shinyjs package. Here I use the btn-primary class in Bootstrap to make the button blue, but you could add your own styling as well.

library(shiny)
library(shinyjs)

ui <- fluidPage(
  useShinyjs(),
  actionButton(inputId = "button1", label = "Select red"),
  actionButton(inputId = "button2", label = "Select blue"),
  plotOutput("distPlot")
)


server <- function(input, output) {
  r <- reactiveValues(my_color = "green")

  output$distPlot <- renderPlot({
    x <- faithful[, 2]
    bins <- seq(min(x), max(x))
    hist(x, breaks = bins, col = r$my_color)
  })

  observeEvent(input$button1, {
    removeClass("button2", "btn-primary")
    addClass("button1", "btn-primary")
    r$my_color <- "red"
  })

  observeEvent(input$button2, {
    removeClass("button1", "btn-primary")
    addClass("button2", "btn-primary")
    r$my_color <- "blue"
  })
}

shinyApp(ui = ui, server = server)