Reporting progress (object-oriented API)

Source: R/progress.R

Reporting progress (object-oriented API)

Reporting progress (object-oriented API)

Details

Reports progress to the user during long-running operations.

This package exposes two distinct programming APIs for working with progress. withProgress() and setProgress() together provide a simple function-based interface, while the Progress reference class provides an object-oriented API.

Instantiating a Progress object causes a progress panel to be created, and it will be displayed the first time the set method is called. Calling close will cause the progress panel to be removed.

As of version 0.14, the progress indicators use Shiny's new notification API. If you want to use the old styling (for example, you may have used customized CSS), you can use style="old" each time you call Progress$new(). If you don't want to set the style each time Progress$new is called, you can instead call shinyOptions(progress.style="old") just once, inside the server function.

See also

withProgress()

Methods

Public methods

Method new()

Creates a new progress panel (but does not display it).

Usage

Progress$new(
  session = getDefaultReactiveDomain(),
  min = 0,
  max = 1,
  style = getShinyOption("progress.style", default = "notification")
)

Arguments

session

The Shiny session object, as provided by shinyServer to the server function.

min

The value that represents the starting point of the progress bar. Must be less than max.

max

The value that represents the end of the progress bar. Must be greater than min.

style

Progress display style. If "notification" (the default), the progress indicator will show using Shiny's notification API. If "old", use the same HTML and CSS used in Shiny 0.13.2 and below (this is for backward-compatibility).

Method set()

Updates the progress panel. When called the first time, the progress panel is displayed.

Usage

Progress$set(value = NULL, message = NULL, detail = NULL)

Arguments

value

Single-element numeric vector; the value at which to set the progress bar, relative to min and max. NULL hides the progress bar, if it is currently visible.

message

A single-element character vector; the message to be displayed to the user, or NULL to hide the current message (if any).

detail

A single-element character vector; the detail message to be displayed to the user, or NULL to hide the current detail message (if any). The detail message will be shown with a de-emphasized appearance relative to message.

Method inc()

Like set, this updates the progress panel. The difference is that inc increases the progress bar by amount, instead of setting it to a specific value.

Usage

Progress$inc(amount = 0.1, message = NULL, detail = NULL)

Arguments

amount

For the inc() method, a numeric value to increment the progress bar.

message

A single-element character vector; the message to be displayed to the user, or NULL to hide the current message (if any).

detail

A single-element character vector; the detail message to be displayed to the user, or NULL to hide the current detail message (if any). The detail message will be shown with a de-emphasized appearance relative to message.

Method getMin()

Returns the minimum value.

Usage

Progress$getMin()

Method getMax()

Returns the maximum value.

Usage

Progress$getMax()

Method getValue()

Returns the current value.

Usage

Progress$getValue()

Method close()

Removes the progress panel. Future calls to set and close will be ignored.

Usage

Progress$close()

Method clone()

The objects of this class are cloneable with this method.

Usage

Progress$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

## Only run examples in interactive R sessions
if (interactive()) {

ui <- fluidPage(
  plotOutput("plot")
)

server <- function(input, output, session) {
  output$plot <- renderPlot({
    progress <- Progress$new(session, min=1, max=15)
    on.exit(progress$close())

    progress$set(message = 'Calculation in progress',
                 detail = 'This may take a while...')

    for (i in 1:15) {
      progress$set(value = i)
      Sys.sleep(0.5)
    }
    plot(cars)
  })
}

shinyApp(ui, server)
}