如何在 Shiny 中跨选项卡持久化 event_data？

Question

我有一个闪亮的应用程序，我想在其中捕获用户单击的哪个栏并将该值存储在反应式表达式中，以便在其他地方引用以进行过滤。问题是当我切换选项卡时反应表达式会重新运行，因此两个选项卡之间的值不会同步。

我在下面有一个可重现的示例。

当您加载应用程序并单击 Goats 栏时，底部的选择会更改为“Goats”，但如果您随后将选项卡更改为 Bar2，则反应式表达式会重新运行，因此会再次返回 Giraffes。因此，我最终为不同选项卡中的反应式表达式提供了两个单独的值。如果我在第一个选项卡上选择山羊，我希望它在我切换到 Bar2 选项卡时保留，并且仅在我再次单击时更新。

请注意，我意识到我可以在此示例中通过从 event_data 函数中删除源参数来解决此问题，但在我的应用程序中，我有其他图表我不希望用户能够点击，所以我需要设置仅这些图表的来源。

library(shiny)
library(plotly)
library(ggplot2)
library(shinydashboard)

df_test <- data.frame(c("Giraffes","Goats"),c(1,4))
df_test <- setNames(df_test,c("species","amount"))

ui <- dashboardPage(

  dashboardHeader(title = "Click Example",
                  titleWidth = 300),
  dashboardSidebar(
    width = 300,
    sidebarMenu(
      menuItem("Tab", tabName = "tab")
    )
  ),
  dashboardBody(
    tabItems(
      tabItem(tabName = "tab",
              fluidRow(
                column(12, tabBox(
                  title = "",
                  id = "tabSet",
                  width = 12,
                  height = 500,
                  tabPanel("Bar1", plotlyOutput(outputId="bar_one")),
                  tabPanel("Bar2", plotlyOutput(outputId="bar_two"))
                )
                ),
                column(12,textOutput(outputId = "selection")))
      )
    )
  )
)

server <- function(input, output, session) {

  click_reactive = reactive({
    d <- event_data("plotly_click",source=input$tabSet)
    if (length(d) == 0) {species = as.vector(df_test$species[1])}
    else {species = as.character(d[4])}
    return(species)
  })

  output$bar_one <- renderPlotly({
    p <- plot_ly(data = df_test, x = ~amount, y = ~species, type = 'bar', orientation = 'h', source = "Bar1")
  })

  output$bar_two <- renderPlotly({
    p <- plot_ly(data = df_test, x = ~amount, y = ~species, type = 'bar', orientation = 'h', source = "Bar2")
  })


  output$selection <- renderText({
    species <- click_reactive()
    return(species)
  })

}

shinyApp(ui, server)

Answer 1

您需要将source 更改为一个名称：

library(shiny)
library(plotly)
library(ggplot2)
library(shinydashboard)

df_test <- data.frame(c("Giraffes","Goats"),c(1,4))
df_test <- setNames(df_test,c("species","amount"))

ui <- dashboardPage(

  dashboardHeader(title = "Click Example",
                  titleWidth = 300),
  dashboardSidebar(
    width = 300,
    sidebarMenu(
      menuItem("Tab", tabName = "tab")
    )
  ),
  dashboardBody(
    tabItems(
      tabItem(tabName = "tab",
              fluidRow(
                column(12, tabBox(
                  title = "",
                  id = "tabSet",
                  width = 12,
                  height = 500,
                  tabPanel("Bar1", plotlyOutput(outputId="bar_one")),
                  tabPanel("Bar2", plotlyOutput(outputId="bar_two"))
                )
                ),
                column(12,textOutput(outputId = "selection")))
      )
    )
  )
)

server <- function(input, output, session) {

  v <- reactiveValues()

  observe({
    d <- event_data("plotly_click",source="Bar1")
    if (length(d) == 0) {species = as.vector(df_test$species[1])}
    else {species = as.character(d[4])}
    v$click <- species
  })

  output$bar_one <- renderPlotly({
    p <- plot_ly(data = df_test, x = ~amount, y = ~species, type = 'bar', orientation = 'h', source = "Bar1")
  })

  output$bar_two <- renderPlotly({
    p <- plot_ly(data = df_test, x = ~amount, y = ~species, type = 'bar', orientation = 'h', source = "Bar1")
  })

  output$selection <- renderText({
    v$click
  })

}

shinyApp(ui, server)