Adjust size of Shiny progress bar and center it - css

Question

I'm working with a Shiny app where I need to calculate processes and while the calc progress is executing, I'm using a progressBar to show the process.
The problem is that the progress bar is too small, and I don't like the way is shown.
So, I was thinking that maybe there's a way to implement a progress bar using a Shiny modal (there's a function called modalDialog).
My idea is that when the user runs the calc, a modal will be opened showing a progressBar.
This is the progress code:
withProgress(message = 'Runing GSVA', value = 0, {
incProgress(1, detail = "This may take a while...")
functionToGenerate()
})
Any idea?

Answer 1

I would suggest customizing the CSS class of the notification:
If you inspect the element of the notifier you see that it has the class "shiny-notification". So you can overwrite some properties of that class with tags$style(). In the example below (for the template: see ?withProgress) i decided to adjust height+width to make it bigger and top+left to center it.
ui <- fluidPage(
tags$head(
tags$style(
HTML(".shiny-notification {
height: 100px;
width: 800px;
position:fixed;
top: calc(50% - 50px);;
left: calc(50% - 400px);;
}
"
)
)
),
plotOutput("plot")
)
server <- function(input, output) {
output$plot <- renderPlot({
withProgress(message = 'Calculation in progress',
detail = 'This may take a while...', value = 0, {
for (i in 1:15) {
incProgress(1/15)
Sys.sleep(0.25)
}
})
plot(cars)
})
}
runApp(shinyApp(ui, server), launch.browser = TRUE)

Answer 2

I wrote a progress bar function in the package shinyWidgets, you can put it in a modal, but it's tricky to use with shiny::showModal, so you can create your own modal manually like the below. It's more code to write but it works fine.
library("shiny")
library("shinyWidgets")
ui <- fluidPage(
actionButton(inputId = "go", label = "Launch long calculation"), #, onclick = "$('#my-modal').modal().focus();"
# You can open the modal server-side, you have to put this in the ui :
tags$script("Shiny.addCustomMessageHandler('launch-modal', function(d) {$('#' + d).modal().focus();})"),
tags$script("Shiny.addCustomMessageHandler('remove-modal', function(d) {$('#' + d).modal('hide');})"),
# Code for creating a modal
tags$div(
id = "my-modal",
class="modal fade", tabindex="-1", `data-backdrop`="static", `data-keyboard`="false",
tags$div(
class="modal-dialog",
tags$div(
class = "modal-content",
tags$div(class="modal-header", tags$h4(class="modal-title", "Calculation in progress")),
tags$div(
class="modal-body",
shinyWidgets::progressBar(id = "pb", value = 0, display_pct = TRUE)
),
tags$div(class="modal-footer", tags$button(type="button", class="btn btn-default", `data-dismiss`="modal", "Dismiss"))
)
)
)
)
server <- function(input, output, session) {
value <- reactiveVal(0)
observeEvent(input$go, {
shinyWidgets::updateProgressBar(session = session, id = "pb", value = 0) # reinitialize to 0 if you run the calculation several times
session$sendCustomMessage(type = 'launch-modal', "my-modal") # launch the modal
# run calculation
for (i in 1:10) {
Sys.sleep(0.5)
newValue <- value() + 1
value(newValue)
shinyWidgets::updateProgressBar(session = session, id = "pb", value = 100/10*i)
}
Sys.sleep(0.5)
# session$sendCustomMessage(type = 'remove-modal', "my-modal") # hide the modal programmatically
})
}
shinyApp(ui = ui, server = server)