Display "downloading" message in shiny-app when processing markdown file [duplicate] - shiny

Question

Is there a built in Shiny attribute that counts the number of times a downloadButton is clicked? I'm not finding it in the function help or web searches. If there's not a built in method how would I go about counting the clicks. Here's a working example:
data <- matrix(1:20, nrow=5)
ui <- fluidPage(title = 'Count Button Clicks',
fluidRow(style = "padding-bottom: 20px;",
column(width=6,
textOutput("actionclickCount"),
br(),
textOutput("downloadclickCount")
),
column(width=6,
actionButton("actionBtn", "Action Button"),
br(),
downloadButton("dwnldBtn", "Download Button")
)
)
)
server <- function(input, output, session) {
output$actionclickCount <- renderText({
paste('Action Button Clicks =',input$actionBtn)
})
output$downloadclickCount <- renderText({
paste('Download Button Clicks =','what variable goes here?')
})
output$dwnldBtn <- downloadHandler(
filename = 'data.csv',
content = function(file){
write.csv(data, file)
},
contentType = 'csv'
)
}
shinyApp(ui = ui, server = server)

Answer 1

I think there is no build-in method. But you could build it yourself.
You can do this by adding a click listener to the button with javascript:
observe({
if(is.null(input$rnd)){
runjs("
var click = 0;
Shiny.onInputChange('rnd', click)
var dwnldBtn = document.getElementById('dwnldBtn')
dwnldBtn.onclick = function() {click += 1; Shiny.onInputChange('rnd', click)};
")
}
})
The output from Shiny.onInputChange('rnd', click) will be accessible in Shiny via input$rnd.
Edit: For multiple buttons you can use:
observe({
for(btn1 in 1:2){
if(is.null(input[[paste0("rnd", btn1)]])){
runjs(
paste0("
var counter", btn1 ,"= 0;
var dwnldBtn = document.getElementById('", paste0("dwnldBtn", btn1), "')
dwnldBtn.onclick = function() {counter", btn1, " +=1; Shiny.onInputChange('", paste0("rnd", btn1), "', counter", btn1,")};
")
)
}
}
})
For a working example see below:
library(shiny)
library(shinyjs)
data <- matrix(1:20, nrow=5)
ui <- fluidPage(title = 'Count Button Clicks',
useShinyjs(),
fluidRow(style = "padding-bottom: 20px;",
column(width=6,
textOutput("actionclickCount"),
br(),
textOutput("downloadclickCount")
),
column(width=6,
actionButton("actionBtn", "Action Button"),
br(),
downloadButton("dwnldBtn", "Download Button")
)
)
)
server <- function(input, output, session) {
output$actionclickCount <- renderText({
paste('Action Button Clicks =',input$actionBtn)
})
output$downloadclickCount <- renderText({
paste('Download Button Clicks =', input$rnd)
})
output$dwnldBtn <- downloadHandler(
filename = 'data.csv',
content = function(file){
write.csv(data, file)
},
contentType = 'csv'
)
observe({
if(is.null(input$rnd)){
runjs("
var click = 0;
Shiny.onInputChange('rnd', click)
var dwnldBtn = document.getElementById('dwnldBtn')
dwnldBtn.onclick = function() {click += 1; Shiny.onInputChange('rnd', click)};
")
}
})
}
runApp(shinyApp(ui = ui, server = server), launch.browser = TRUE)