How to disable an actionButton until a computation is finished ?

[Olivier Savriama]

Hey guys, is there a way to disable a "goButton" in charge of starting computationally expensive operations until the operations are done and then re-enable it ? 1/ I've tried the shinyBS package with the bsActionButton() and updateButton() but no way it doesn't work. 2/ Implementing javascript is a bit too hard for me at the moment. Thanks.

[David Wahman]

Here is one option that may work.  This following code will make the action button "disappear" until the compution is complete.  Because of the conditional panel, it only displays the button when shiny is "not busy".

 

conditionalPanel(condition = "!$('html').hasClass('shiny-busy')",   
         actionButton("ButtonId", label = "my button ID text"))

[Olivier Savriama]

Hi David, thanks but it doesn't work.

By the way is it possible to create a reactive variable in "server.R" which indicates that a computation is finished and then use it in the condition field of your conditionalPanel ?

Thanks.

[Olivier Savriama]

Hi,

I've found a solution with javascript thanks to this link: https://stackoverflow.com/questions/25247852/shiny-app-disable-downloadbutton/25250376#25250376?newreg=5c858561320643be97918ce2ad71b6a6

Here is my code:

# ui.R

library(shiny)

shinyUI(fluidPage(

  singleton(tags$head(HTML(

    '

    <script type="text/javascript">

    $(document).ready(function() {

    

    // disable start_proc button after a click

    Shiny.addCustomMessageHandler("disableButton", function(message) {

    $("#start_proc").attr("disabled", "true");

    });

    

    // Enable start_proc button when computation is finished

    Shiny.addCustomMessageHandler("enableButton", function(message) {

    $("#start_proc").removeAttr("disabled");

    });

})

    </script>

    '

))),

  tabsetPanel(

    tabPanel('Enable/Disable Start Button',

      actionButton("start_proc", h5("Start Button")),

      hr(),

      helpText("Start Button will be available once the computation (5 seconds) is completed.")

    )

  )

))

# server.R

library(shiny)

fakeDataProcessing <- function(duration) {

  # does nothing but sleep for "duration" seconds while

  # pretending some background task is going on...

  Sys.sleep(duration)

}

shinyServer(function(input, output, session) {

  

  observe({

    if (input$start_proc > 0) {

      # Notify the browser that the computation is running

      session$sendCustomMessage("disableButton", "start_proc")

      print("Computation is running.")

      fakeDataProcessing(5)

      # Notify the browser that the computation is finished

      session$sendCustomMessage("enableButton", "start_proc")

      print("Computation is done.")

    }

  })

})

Can anybody tell me how to print my messages "Computation is running." and "Computation is done." in a textOutput in real time ?

[Joe Cheng]

Shiny 10.2 (which is coming out in the next couple of weeks) has a progress API that can be used for "Computation is running". You can install it from GitHub by using

if (!require("devtools"))

  install.packages("devtools")

devtools::install_github("rstudio/shiny")

then do ?shiny::withProgress to see the help topic.

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[Olivier Savriama]

Hi Joe,

Thanks, it's very useful.

[Winston Chang]

Also see this for more information on progress indicators:
http://rpubs.com/wch/28353

On Tue, Sep 16, 2014 at 11:59 PM, Olivier Savriama

> https://groups.google.com/d/msgid/shiny-discuss/3a8190da-dc37-4fd2-a634-2974714ebff7%40googlegroups.com.

[Olivier Savriama]

Hi Chang,

That's great !

Thank you,

Olivier.

[k.kos...@gmail.com]

Hi, can you show an example of how this would be used?