Question

我的Shiny应用程序的主要目标是通过（交互式）ggplots显示大量数据。有了足够的数据，显示图表所需的时间可能会长达10秒左右，我想显示一个进度条以提供反馈。

我已经尝试了withProgress和winProgressBar，但是都没有反映出ggplots的显示时间：两个进度条都在显示实际绘图之前很久就消失了。

所以我的问题是：如何实现（任何类型的）进度条以反映ggplots在屏幕上显示所花费的时间？

library(shiny)
library(ggplot2)
library(dplyr)

ui = fluidPage(
    mainPanel(
      uiOutput("plots")
    )
)

server = function(input, output) {

  #list of things I want to plot, which will be split over column wt
  plotlist = sort(unique(mtcars$wt))[1:4]

  observe({
    pb = winProgressBar(                                 #test 1: winProgressBar
      title = 'observe',                                 #test 1: winProgressBar
      label = 'plotting'                                 #test 1: winProgressBar
    )                                                    #test 1: winProgressBar
    message({                                            #test 1: winProgressBar

      withProgress(message = 'ggplotting', value = 0, {  #test 2: withProgress

        for (i in plotlist) local({

          nm <- i
          temp.data <- filter(mtcars, wt == plotlist[nm])

          plotAname  <- paste0("plotA", nm)
          output[[plotAname]] <- renderPlot(ggplot(temp.data, aes(x = mpg, y= cyl)) + geom_point())

          plotBname  <- paste0("plotB", nm)
          output[[plotBname]] <- renderPlot(ggplot(temp.data, aes(x = mpg, y= drat)) + geom_point())

          plotCname  <- paste0("plotC", nm)
          output[[plotCname]] <- renderPlot(ggplot(temp.data, aes(x = mpg, y= disp)) + geom_point())

          plotDname  <- paste0("plotD", nm)
          output[[plotDname]] <- renderPlot(ggplot(temp.data, aes(x = mpg, y= hp)) + geom_point())

          setWinProgressBar(pb, value = nm/10)         #test 1: winProgressBar
          incProgress(1/(length(plotlist)))            #test 2: withProgress
        }) #end of for()
      }) #end of withProgress                          #test 2: withProgress

    close(pb)                                          #test 1: winProgressBar
    }) #end of message                                 #test 1: winProgressBar
  }) #end of observe

  output$plots <- renderUI({

    withProgress(message = 'rendering', value = 0, {   #test 3: withProgress

      plot_output_list <- lapply(plotlist, function(i) { 

        incProgress(1/(length(plotlist)))              #test 3: withProgress

        #encompass everything in a div because lapply can only returns a single result per loop cycle. 
        div(style = "padding: 0px; margin: 0px;",
            div(style = "position:relative; margin-bottom: -5px; padding: 0px;",
                plotOutput(paste0("plotA", i))
            ),
            div(style = "position:relative; margin-bottom: -5px; padding: 0px;",
                plotOutput(paste0("plotB", i))
            ),
            div(style = "position:relative; margin-bottom: -5px; padding: 0px;",
                plotOutput(paste0("plotC", i))
            ),
            plotOutput(paste0("plotD", i))
        )
      }) #end of lapply
    }) #end of withProgress                          #test 3: withProgress
  }) #end of output$plots

}

shinyApp(ui = ui, server = server)

此示例大约需要4秒钟才能显示其图。所有三个测试进度条都在大约1秒钟后结束。

感谢您抽出宝贵的时间来完成此工作！如果可以提供任何说明，请告诉我。

Answer 1

实际上并不是您想要生成的进度条。但是您可以改为在横幅内显示加载消息，这就是为什么我认为它在这里可能有用的原因。只需将以下代码段复制到应用的ui部分中，然后根据需要调整颜色即可。

info_loading <- "Shiny is busy. Please wait."
your_color01 <- # define a color for the text
your_color02 <- # define a color for the background of the banner

tags$head(tags$style(type="text/css",
                                      paste0("
                                             #loadmessage {
                                             position: fixed;
                                             top: 0px;
                                             left: 0px;
                                             width: 100%;
                                             padding: 5px 0px 5px 0px;
                                             text-align: center;
                                             font-weight: bold;
                                             font-size: 100%;
                                             color: ", your_color01,";
                                             background-color: ", your_color02,";
                                             z-index: 105;
                                             }
                                             "))),
                 conditionalPanel(condition="$('html').hasClass('shiny-busy')",
                                  tags$div(info_loading,id="loadmessage"))

请根据需要随时调整参数（例如顶部位置）。您可能还会看到：shiny loading bar for htmlwidgets

添加进度条以指示Shiny中的ggplotting进度

1 个答案: