introduction

In waiter: Loading Screen for 'Shiny'

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

The waiter package comes with a few members of staff but the core one is the waiter which will let you show full page or partial loading screens in your shiny application.

It's fairly straightforward:

1. Place useWaiter anywhere in your UI.
2. Create a waiter with Waiter$new()
3. Show the waiter with Waiter$show()
4. Hide the waiter with Waiter$hide()

Examples

A basic example could be like this, upon clicking a button we display a full page loading screen.

library(shiny)
library(waiter)

ui <- fluidPage(
  useWaiter(), # include dependencies
  actionButton("show", "Show loading for 3 seconds")
)

server <- function(input, output, session){
  # create a waiter
  w <- Waiter$new()

  # on button click
  observeEvent(input$show, {
    w$show()
    Sys.sleep(3)
    w$hide()
  })
}

shinyApp(ui, server)

Make sure you include the dependencies with useWaiter or nothing will work.

By default the waiter will show a spinner, 1) you can choose from more than 100 spinners 2) you are by no means limited to a spinner since the html argument takes any htmltools or shiny tag. Below we change the spinner, add some text and change the background color.

library(shiny)
library(waiter)

waiting_screen <- tagList(
  spin_flower(),
  h4("Cool stuff loading...")
) 

ui <- fluidPage(
  useWaiter(), # include dependencies
  actionButton("show", "Show loading for 3 seconds")
)

server <- function(input, output, session){
  observeEvent(input$show, {
    waiter_show(html = waiting_screen, color = "black")
    Sys.sleep(3) # do something that takes time
    waiter_hide()
  })
}

shinyApp(ui, server)

Visit the full waiter documentation to learn how to further customise your waiting screen, have it appear on parts of the application, show loading bars, and more.

waiter documentation built on Jan. 3, 2022, 5:13 p.m.