Reporting progress (object-oriented API)

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")`][shinyOptions] just once, inside the server function.

See also

[with_progress()]

Methods

Public methods

• Progress$new()

• Progress$set()

• Progress$inc()

• Progress$getMin()

• Progress$getMax()

• Progress$getValue()

• Progress$close()

• Progress$clone()

---

Method new()

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

Usage

Progress$new(session = getDefaultReactiveDomain(), min = 0, max = 1, ...)

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`.

...

Arguments that may have been used for `shiny::Progress`

---

Method set()

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

Usage

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

...

Arguments that may have been used for `shiny::Progress`

---

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, ...)

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).

...

Arguments that may have been used for `shiny::Progress`

---

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 <- semanticPage(
  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')

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

shinyApp(ui, server)
}