R有光澤的隱藏mainPanel對象在計算時間

Question

我有一個閃亮的應用程序，具有更長的計算取決於輸入。我想知道是否可以在計算完成的同時（而不是之前）在主面板中顯示文本。

讓我們來舉個簡單的例子。我模擬了長計算與Sys.sleep()：

# Define UI for application that draws a histogram 

ui <- shinyUI(fluidPage(

# Application title 
    titlePanel("Old Faithful Geyser Data"), 

# Sidebar with a slider input for number of bins 
    sidebarLayout(
     sidebarPanel(
     sliderInput("bins", 
        "Number of bins:", 
        min = 1, 
        max = 50, 
        value = 30) 
    ), 

     # Show a plot of the generated distribution 
     mainPanel(
     h3('This is an example'), 
     plotOutput("distPlot") 
    ) 
    ) 
)) 

# Define server logic required to draw a histogram 
server <- shinyServer(function(input, output) { 

    output$distPlot <- renderPlot({ 
     # generate bins based on input$bins from ui.R 
     x <- faithful[, 2] 
     bins <- seq(min(x), max(x), length.out = input$bins + 1) 

     # draw the histogram with the specified number of bins 
     hist(x, breaks = bins, col = 'darkgray', border = 'white') 
     Sys.sleep(5) 
    }) 
}) 

# Run the application 
shinyApp(ui = ui, server = server) 

的目標是，以顯示在同一時間計算完成，而不是之前的文本「這是一個例子。」 我認爲我必須使文本以某種方式反應，但到目前爲止我還沒有找到解決方案。也許一個conditionalPanel可以做到這一點，但我怎樣才能使條件的計算時間？有任何想法嗎？

Answer 1

這是你要搜索的嗎？在觀察distPlot事件後，將您的文本變量作爲反應變量

library(shiny) 
# Define UI for application that draws a histogram 

ui <- shinyUI(fluidPage(

    # Application title 
    titlePanel("Old Faithful Geyser Data"), 

    # Sidebar with a slider input for number of bins 
    sidebarLayout(
    sidebarPanel(
     sliderInput("bins", 
        "Number of bins:", 
        min = 1, 
        max = 50, 
        value = 30) 
    ), 
    # Show a plot of the generated distribution 
    mainPanel(
     textOutput('text1'), 
     plotOutput("distPlot") 
    ) 
) 
)) 

# Define server logic required to draw a histogram 
server <- shinyServer(function(input, output) { 
    output$distPlot <- renderPlot({ 
    # generate bins based on input$bins from ui.R 
    x <- faithful[, 2] 
    bins <- seq(min(x), max(x), length.out = input$bins + 1) 
    # draw the histogram with the specified number of bins 
    hist(x, breaks = bins, col = 'darkgray', border = 'white') 
    Sys.sleep(2) 

    }) 
    observeEvent(plotOutput("distPlot"), { 
    output$text1 <- renderText({ paste("Number of bins:", input$bins)}) 
    }) 
    }) 

# Run the application 
shinyApp(ui = ui, server = server)