在 Rshiny 中复制 GoogleVis 图表

Question

I need the same googlevis chart more than once in my Rshiny dashboard but when I try to do this, charts do not load properly.

For example, in the following code, if I plot the chart one time only it runs fine. Otherwise, both charts don't load. Any thoughts?

## app.R ##
library(shiny)
library(shinydashboard)
suppressPackageStartupMessages(library(googleVis))

ui <- dashboardPage(
  dashboardHeader(title = "Basic dashboard"),
  dashboardSidebar(),
  dashboardBody(

    fluidRow(box(htmlOutput("plot", height = 350))),
    fluidRow(box(htmlOutput("plot", height = 350)))
  )
)

server <- function(input, output) {
  set.seed(122)
  histdata <- rnorm(500)

  output$plot <- renderGvis({ gvisBubbleChart(Fruits, idvar="Fruit", 
                                              xvar="Sales", yvar="Expenses",
                                              colorvar="Year", sizevar="Profit",
                                              options=list(
                                                hAxis='{minValue:75, maxValue:125}')) })

}

shinyApp(ui, server)

Answer 1

Replicated code is bad style. You better use a (reactive) function for that. In your case, reactive is not necessary (since it's a fixed chart), but in most practical cases you will use reactive values there:

library(shinydashboard)
suppressPackageStartupMessages(library(googleVis))

ui <- dashboardPage(
  dashboardHeader(title = "Basic dashboard"),
  dashboardSidebar(),
  dashboardBody(

    fluidRow(box(htmlOutput("plot1", height = 350))),
    fluidRow(box(htmlOutput("plot2", height = 350)))
  )
)

server <- function(input, output) {
  # a bubble chart that can be called anytime
  chart <- reactive({
    gvisBubbleChart(Fruits, idvar="Fruit", 
                    xvar="Sales", yvar="Expenses",
                    colorvar="Year", sizevar="Profit",
                    options=list(
                      hAxis='{minValue:75, maxValue:125}')) 
  })

  # two plots using the bubble chart
  output$plot1 <- renderGvis({   chart() })  
  output$plot2 <- renderGvis({   chart() })      
}

shinyApp(ui, server)

Answer 2

To my knowledge, Shiny does not allow one output variable more than once in UI. One quick and easy fix is just to replicate your chart as following:

## app.R ##
library(shiny)
library(shinydashboard)
suppressPackageStartupMessages(library(googleVis))

ui <- dashboardPage(
  dashboardHeader(title = "Basic dashboard"),
  dashboardSidebar(),
  dashboardBody(

    fluidRow(box(htmlOutput("plot1", height = 350))),
    fluidRow(box(htmlOutput("plot2", height = 350)))
  )
)

server <- function(input, output) {
  set.seed(122)
  histdata <- rnorm(500)

  output$plot1 <- renderGvis({ gvisBubbleChart(Fruits, idvar="Fruit", 
                                              xvar="Sales", yvar="Expenses",
                                              colorvar="Year", sizevar="Profit",
                                              options=list(
                                                hAxis='{minValue:75, maxValue:125}')) })

  output$plot2 <- renderGvis({ gvisBubbleChart(Fruits, idvar="Fruit", 
                                               xvar="Sales", yvar="Expenses",
                                               colorvar="Year", sizevar="Profit",
                                               options=list(
                                                 hAxis='{minValue:75, maxValue:125}')) })

}

shinyApp(ui, server)