How to select multiple folders with shinyDirButton in R - r

Question

I'm trying to write a small shiny app where the user can select multiple folders through a button. The number of folders selected varies according to the needs of the user. The selection of one folder works. If I set "multiple = TRUE", then also only one folder is selected. Does anyone have an idea how I can select multiple folders with a single button?
Here is my code:
library(shiny)
library(shinydashboard)
library(shinyFiles)
library(shinyWidgets)
ui <- fluidPage(
shinyDirButton("preinfolder", "Choose a folder" ,
title = "Please select a folder:",
buttonType = "default", class = NULL,
icon = icon("folder", lib = "font-awesome"), multiple = TRUE),
textOutput("prein_txt_file")
)
server <- function(input, output, session) {
volumes = getVolumes()()
observe({
shinyDirChoose(input, "preinfolder", roots = volumes, session = session)
if(!is.null(input$preinfolder)){
# browser()
preinfolder_selected<-parseDirPath(volumes, input$preinfolder)
output$prein_txt_file <- renderText(preinfolder_selected)
}})
}
shinyApp(ui, server)
Thanks for any idea

Answer 1

I am still trying to solve the problem. I want a list of selected folders.
For my previous solution, I can select multiple folders but only from one parent folder.
library(shiny)
library(shinydashboard)
library(shinyFiles)
library(shinyWidgets)
ui <- fluidPage(
shinyDirButton("preinfolder", "Choose a folder" ,
title = "Please select a folder:",
buttonType = "default", class = NULL,
icon = icon("folder", lib = "font-awesome"), multiple = TRUE),
uiOutput(outputId = "sel_subfolder"),
textOutput("prein_txt_file")
)
server <- function(input, output, session){
volumes = getVolumes()()
observe({
shinyDirChoose(input, "preinfolder", roots = volumes, session = session)
if(!is.null(input$preinfolder)){
# browser()
preinfolder_selected<-parseDirPath(volumes, input$preinfolder)
output$prein_txt_file <- renderText(preinfolder_selected)
}})
df <- reactive({
if(is.null(input$preinfolder)) {
return(NULL)
} else {
fol <- parseDirPath(volumes, input$preinfolder)
return(fol)
}
})
output$sel_subfolder <- renderUI({
if(is.null(df())) {
return(NULL)
} else if(!is.null(df())) {
return(tags$div(align = "left",
class = "multicol",
checkboxGroupInput(inputId = "sel_subfolder",
label = "Select subfolder",
choices = unlist(list.files(parseDirPath(volumes, input$preinfolder))))))
}
})
}
shinyApp(ui, server)
I am still looking for a solution how to create a list of multiple folders with one input button.

Answer 2

This is the solution I found (a bit convoluted but it works).
You basically pass the selected folder to a updateCheckboxGroupInput function that appends the folder to a list of previously chosen ones
library(shiny)
library(shinyFiles)
ui <- fluidPage(
titlePanel("Test"),
sidebarLayout(
sidebarPanel(
shinyDirButton('fld','Choose...','Choose a folder'),
actionButton("submitbutton", "Add folder", class = "btn btn-primary"),
checkboxGroupInput('chosenfolders','Chosen folders...')
),
mainPanel(
verbatimTextOutput("selected")
)
)
)
server <- function(input, output, session) {
volumes <- c(Home = fs::path_home(), "R Installation" = R.home(), getVolumes()())
shinyDirChoose(input, 'fld', session=session,
root=volumes, filetypes=c('txt'))
datasetInput <- reactive({
inputfolders <- c(input$chosenfolders,
parseDirPath(volumes, input$fld))
updateCheckboxGroupInput(session, 'chosenfolders',
choices = inputfolders,
selected = inputfolders)
print(list('Input folders' = inputfolders))
})
output$selected <- renderPrint({
if (input$submitbutton>0) {
isolate(datasetInput())
} else {
return("Server is ready for calculation.")
}
})
}
shinyApp(ui = ui, server = server)