背景

在模块化1闪亮的应用程序中，我只想在shinydashboard上的菜单项被单击时加载模块。如果未访问菜单项，我不想加载模块。

基础应用

app.R

# Libs
library(shiny)
library(shinydashboard)

# Source module
source("sample_module.R")

ui <- dashboardPage(
    dashboardHeader(title = "Dynamic sidebar"),
    dashboardSidebar(sidebarMenuOutput("menu")),
    dashboardBody(tabItems(
        tabItem(tabName = "tab_one", h1("Tab One")),
        tabItem(tabName = "tab_two", sampleModuleUI("sampleModule"))
    ))
)

server <- function(input, output) {

    callModule(sampleModuleServer, "sampleModule")

    output$menu <- renderMenu({
        sidebarMenu(
            menuItem(
                "Menu item 1",
                icon = icon("calendar"),
                tabName = "tab_one"
            ),
            menuItem(
                "Menu item 2",
                icon = icon("globe"),
                tabName = "tab_two"
            )
        )
    })
}

shinyApp(ui, server)

sample_module.R

sampleModuleServer <- function(input, output, session) {
    output$plot1 <- renderPlot({
        plot(mtcars)
    })
}

sampleModuleUI <- function(id) {
    ns <- NS(id)

    plotOutput(ns("plot1"))

}

所需实施

不要从观察事件内部调用调用模块；请将其保持在顶层。获取返回的反应式表达式，并使用EventReactive将其包装在按钮单击中。并从您的输出中使用EventReactive等。

x <- callModule(...)
y <- eventReactive(input$go, x())
output$tbl <- DT::renderDataTable(y())

尝试

app.R(已修改)

# Libs
library(shiny)
library(shinydashboard)

# Source module
source("sample_module.R")

ui <- dashboardPage(
    dashboardHeader(title = "Dynamic sidebar"),
    dashboardSidebar(sidebarMenuOutput("menu")),
    dashboardBody(tabItems(
        tabItem(tabName = "tab_one", h1("Tab One")),
        tabItem(tabName = "tab_two", sampleModuleUI("sampleModule"))
    ))
)

server <- function(input, output) {

    eventReactive(eventExpr = input$tab_two,
                  valueExpr = callModule(sampleModuleServer, "sampleModule")
    )

    output$menu <- renderMenu({
        sidebarMenu(
            menuItem(
                "Menu item 1",
                icon = icon("calendar"),
                tabName = "tab_one"
            ),
            menuItem(
                "Menu item 2",
                icon = icon("globe"),
                tabName = "tab_two"
            )
        )
    })
}

shinyApp(ui, server)

问题

应用程序运行，但模块未加载。问题：

单击菜单项%2应会显示sample_module.R文件中的内容。

1Modularizing Shiny app code

2Google groups: activate module with actionButton

更新

我尝试使用以下语法显式强制将模块加载到应用程序环境中：

eventReactive(eventExpr = input$tab_two,
              valueExpr = callModule(sampleModuleServer, "sampleModule"),
              domain = MainAppDomain
)

在哪里

MainAppDomain <- getDefaultReactiveDomain()

推荐答案

编辑：删除郑志刚的顶层声明：

# Libs
library(shiny)
library(shinydashboard)

# Source module
source("sample_module.R")

ui <- dashboardPage(
  dashboardHeader(title = "Dynamic sidebar"),
  dashboardSidebar(sidebarMenuOutput("menu")),
  dashboardBody(tabItems(
    tabItem(tabName = "tab_one", h1("Tab One")),
    tabItem(tabName = "tab_two", sampleModuleUI("sampleModule"))
  ))
)

server <- function(input, output) {

  observeEvent(input$tabs,{
    if(input$tabs=="tab_two"){
      callModule(sampleModuleServer, "sampleModule")
    }
  }, ignoreNULL = TRUE, ignoreInit = TRUE)

  output$menu <- renderMenu({
    sidebarMenu(id = "tabs",
                menuItem(
                  "Menu item 1",
                  icon = icon("calendar"),
                  tabName = "tab_one"
                ),
                menuItem(
                  "Menu item 2",
                  icon = icon("globe"),
                  tabName = "tab_two"
                )
    )
  })
}

shinyApp(ui, server)

此外，您的sidebarMenu需要ID才能访问选定的选项卡；请参阅shinydashboarddocumentation。