R Shiny中点击valueBox链接触发selectInput更新的问题

问题根因 #

你代码的核心问题出在updateSelectInput的selected参数赋值不匹配：你定义的choices结构是c(显示名 = 实际值)，即显示名是pdf1/pdf2，组件实际返回的选中值是PDF的存储路径，你在更新时给selected传了显示名pdf1，而不是对应的实际路径，所以更新失效。
除此之外，原有简化代码还漏写了dashboardPage必填的头部、侧边栏参数，也会导致运行报错。

修正后可运行完整代码 #

# 先加载必要依赖包
library(shiny)
library(shinydashboard)
library(shinyjs)

shinyServer(function(input, output, session){
  
  observeEvent(input$link1, {
    # selected参数传对应PDF的实际路径，选项目录不变无需重复传choices
    updateSelectInput(session, 
                      inputId = "pdf_selection",
                      selected = "location/pdf1.pdf")
    # 如果你需要跨标签页跳转，放开下方注释，替换为你自己的菜单ID、标签页ID即可
    # updateTabItems(session, "your_menu_id", selected = "your_pdf_tab_id")
  })
  
  observeEvent(input$link2, {
    updateSelectInput(session, 
                      inputId = "pdf_selection",
                      selected = "location/pdf2.pdf")
    # 同上可加跳转逻辑
  })
  
  output$pdfView <- renderUI({
    req(input$pdf_selection) # 加req避免初始无值时报错
    tags$iframe(style = "height:800px;width:100%", src = input$pdf_selection)
  })
  
  output$stat1 <- renderValueBox({
    valueBox(subtitle = "fact 1", 
             value = actionLink(inputId = "link1", 
                                label = HTML("Some statistic to report1")))
  })
  
  output$stat2 <- renderValueBox({
    valueBox(subtitle = "fact 2", 
             value = actionLink(inputId = "link2", 
                                label = HTML("Some statistic to report2")))
  })
  
})

shinyUI(fluidPage(
  dashboardPage(
    dashboardHeader(), # 补全必填的头部参数
    dashboardSidebar(), # 补全必填的侧边栏参数
    dashboardBody(
      useShinyjs(),
      fluidRow(valueBoxOutput("stat1"), valueBoxOutput("stat2")),
      
      selectInput(inputId = "pdf_selection",
                  label = "select pdf",
                  choices = c("pdf1" = "location/pdf1.pdf", "pdf2" = "location/pdf2.pdf"),
                  selected = "location/pdf1.pdf"), # 初始值设为第一个PDF路径
      
      htmlOutput("pdfView")
    )
  )
))

验证注意事项 #

• 把代码里的location/pdf1.pdf替换为你实际的PDF存储路径，本地文件需要放在Shiny应用的www目录下才能正常加载
• 点击valueBox内的链接后，selectInput选中项会同步切换，PDF预览也会自动更新

内容的提问来源于stack exchange，提问作者PeterI