reset R shiny actionButton to use it more than once

Question

Does someone know how to make actionButton (R shiny) reset to initial value in order to use it more than once?

Please find below a reproductible example:

In this example, I would like to change the chart color by selecting the corresponding button: my issue is that it cannot reload the chart after one iteration.

library(shiny)

ui <- fluidPage(

  actionButton(inputId = "button1",label = "Select red"),
  actionButton(inputId = "button2",label = "Select blue"),
  plotOutput("distPlot")

)


server <- function(input, output) {

   output$distPlot <- renderPlot({
      x    <- faithful[, 2] 
      bins <- seq(min(x), max(x))

      my_color <- "green"
      if (input$button1){my_color <- "red"}
      if (input$button2){my_color <- "blue"}

      hist(x, breaks = bins, col = my_color)
   })
}

shinyApp(ui = ui, server = server)

Thank you in advance

score 7 · Accepted Answer · answered May 09 '18 at 12:55

7

It's not good idea to reset ActionButton in Shiny usually. I would suggest you to use ObserveEvent and store the color into reactiveValues.

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)

answered May 09 '18 at 12:55

mbh86

6,078
3
18
31

Do you know if this is also possible with only one `observeEvent`? and a `ifelse` or `case_when` function? like: `observeEvent(c(input$button1, input$button2){ r$my_color <- case_when(input$button1 > 0 ~ "red", input$button2 > 0 ~ "blue" })` I can't really get something like this to work. – Kevin Mar 19 '21 at 14:42
@Kevin Have you checked this? https://stackoverflow.com/questions/41960953/how-to-listen-for-more-than-one-event-expression-within-a-shiny-observeevent – mbh86 Mar 24 '21 at 09:13
Yes I have seen that one, however it does not work for my case. After using all the color options once, the Shiny-app freezes. The above solution works better in my case. Thanks for the suggestion. – Kevin Mar 26 '21 at 10:39

reset R shiny actionButton to use it more than once

1 Answers1