Progress: Reporting progress (object-oriented API)
In ymd526442121/Rproject_shiny: Web Application Framework for R

Description Arguments Details See Also Examples

Reports progress to the user during long-running operations.

`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`. `NULL` hides the progress bar, if it is currently visible.
`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.

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.

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.

withProgress

## 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)
}