shinyfiles and renderUI don't work properly - r

Question

I'm trying to use the shinyFiles library in my shinyApp, in order to give the user the possibility to select a group of files or a directory.
My idea is to use a uiOutput that changes depending on a checkbox selection.
Here I report the code, that maybe is more explicative than words
UtilityUI <- fluidPage(
titlePanel("page1"),
fluidRow(
column(2,
wellPanel(
tags$p("Check the box below if you want to choose an entire directory"),
checkboxInput(inputId = 'directory_flag', label = 'Directory path?', value = FALSE),
uiOutput("input_selection_ui")
)
),
column(8
#...
)
)
)
UtilityServer <- function(input, output, session) {
output$input_selection_ui <- renderUI({
if(input$directory_flag == TRUE) {
shinyDirButton(id = "infiles", label = "Choose directory", title = "Choose a directory")
} else {
shinyFilesButton(id = "infiles", label = "Choose file(s)", title = "Choose one or more files", multiple = TRUE)
}
})
shinyFileChoose(input, 'infiles', roots=getVolumes(), session=session, restrictions=system.file(package='base'))
shinyDirChoose(input, 'infiles', roots=getVolumes(), session=session, restrictions=system.file(package='base'))
}
shinyApp(UtilityUI, UtilityServer)
The problem borns when the "shinyFiles" button is pressed: the popup window doesn't load the roots, in both cases (shinyDirButton and shinyFilesButton).
If I don't use the uiOutput function everything works well... But in that case I cannot change my UI dinamically...
Thanks a lot for your replies,
Inzirio

Answer 1

It seems I can't get it to work either with renderUI(). Instead I implemented the same behavior using conditionalPanel() to show alternative buttons. This seems to work. Here is the code:
ui <- shinyUI(fluidPage(
checkboxInput(
inputId = 'directory_flag',
label = 'Directory path?',
value = FALSE
),
conditionalPanel(
"input.directory_flag == 0",
shinyFilesButton(
id = "infile",
label = "Choose file(s)",
title = "Choose one or more files",
multiple = TRUE
)
),
conditionalPanel(
"input.directory_flag == 1",
shinyDirButton(id = "indir", label = "Choose directory", title = "Choose a directory")
)
))
server <- shinyServer(function(input, output, session) {
shinyFileChoose(
input,
'infile',
roots = getVolumes(),
session = session,
restrictions = system.file(package = 'base')
)
shinyDirChoose(
input,
'indir',
roots = getVolumes(),
session = session,
restrictions = system.file(package = 'base')
)
})
shinyApp(ui, server)