R: Reporting progress (object-oriented API)

Progress {shiny} | R Documentation

## Reporting progress (object-oriented API)

### Description

Reports progress to the user during long-running operations.

### 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 tham `max`.
`max` | The value that represents the end of the progress bar. Must be greater than `min`.
`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`.
`value` | A numeric value at which to set the progress bar, relative to `min` and `max`.
`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).
`amount` | 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.
`amount` | For the `inc()` method, a numeric value to increment the progress bar.

### Details

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.

Methods

`initialize(session, min = 0, max = 1)`

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

`set(value = NULL, message = NULL, detail = NULL)`

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

`inc(amount = 0.1, message = NULL, detail = NULL)`

  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.

`close()`

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

### See Also

`withProgress`

### 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)
    }

[Package shiny version 1.2.0 Index]