Shiny Dashboard：在不同的Tabitem中导航时，重置条件面板状态

Question

我有以下代码，其中仪表板上有各种条件面板。 如果我们从一个条件面板导航到仪表板中的下一个，然后转到小部件，最后返回仪表板，则该仪表板处于先前状态。 当我从另一个选项卡面板返回时，我希望仪表板刷新（重置为原始状态）。 有可能这样做吗？

library(shiny)
library(shinydashboard)
library(maps)
library(leaflet)

ui <- dashboardPage(
  dashboardHeader(title = "Dashboard"),
  dashboardSidebar(sidebarMenu(
    menuItem("Dashboard", tabName = "dashboard", icon = icon("dashboard")),
    menuItem("Widgets", tabName = "widgets", icon = icon("th"))
  )),
  dashboardBody(
    tabItems(
      # First tab content
      tabItem(tabName = "dashboard",
      tags$script("
                  Shiny.addCustomMessageHandler('resetInputValue', function(variableName){
                  Shiny.onInputChange(variableName, null);
                  });
                  "),

      conditionalPanel(
        condition <- "input.link_click  === undefined || input.link_click === null",
        leafletOutput("Map", width = 1000, height = 500)

      ),


      conditionalPanel(
        condition <- "(input.link_click_Site  === undefined || input.link_click_Site === null) && (input.link_click  !== undefined && input.link_click !== null)",

        leafletOutput("CountryMap", width = 1000, height = 500)

      ),
      conditionalPanel(
        condition <- "(input.link_click_Site  !== undefined && input.link_click_Site !== null)",

        h3("Plots related to site chosen"),
        textOutput(outputId = "Check"),
        actionButton("Back", "Back")
      )
     ),
     tabItem(tabName = "widgets",
             h3("This is widget page")

             )
     )
  )
)


server <- function(input, output, session){
  Country = map("world", fill = TRUE, plot = FALSE, regions="USA")
  output$Map <- renderLeaflet({
    leaflet(Country) %>% addTiles() %>%  setView(0, 0,  zoom = 2)%>%
      #leaflet(target) %>% addTiles() %>%
      addPolygons(fillOpacity = 0.6,
                  fillColor = 'blue',
                  smoothFactor = 0.5, stroke = TRUE, weight = 1, popup =  paste("<b>", "USA", "</b><br>",
                                                                                actionLink(inputId = "View", 
                                                                                           label = "View Details", 
                                                                                           onclick = 'Shiny.onInputChange(\"link_click\",  Math.random())')))
  })

  output$CountryMap <- renderLeaflet({

    leaflet(Country) %>% addTiles() %>%   
      fitBounds(Country$range[1], Country$range[3], Country$range[2], Country$range[4])%>%
      addMarkers(lng = -71.03 , lat = 42.37, popup = paste("<b>", "Boston", "</b><br>",
                                                           actionLink(inputId = "View", 
                                                                      label = "View Details", 
                                                                      onclick = 'Shiny.onInputChange(\"link_click_Site\",  Math.random())')))
  })

  observeEvent(input$link_click_Site, {
    output$Check <- renderText("Success")

  })

  observeEvent(input$Back, {
    session$sendCustomMessage(type = 'resetInputValue', message = "link_click_Site")
    session$sendCustomMessage(type = 'resetInputValue', message = "link_click")
  })

}


shinyApp(ui =ui, server = server)

Answer 1

每当切换面板时，都可以使用与单击“后退”按钮时重置视图相同的代码来重置视图。

您只需为侧边栏提供一个id ，然后您就可以收听此ID的输入，它告诉您哪个面板处于活动状态。 下面的解决方案是一个最小的解决方案，仅增加了两个： sidebarMenu获取一个输入id， id = "mySidebar" ，而observeEvent观察第二个变量input$mySidebar 。

library(shiny)
library(shinydashboard)
library(maps)
library(leaflet)

ui <- dashboardPage(
  dashboardHeader(title = "Dashboard"),
  dashboardSidebar(sidebarMenu(id = "mySidebar",
    menuItem("Dashboard", tabName = "dashboard", icon = icon("dashboard")),
    menuItem("Widgets", tabName = "widgets", icon = icon("th"))
  )),
  dashboardBody(
    tabItems(
      # First tab content
      tabItem(tabName = "dashboard",
      tags$script("
                  Shiny.addCustomMessageHandler('resetInputValue', function(variableName){
                  Shiny.onInputChange(variableName, null);
                  });
                  "),

      conditionalPanel(
        condition <- "input.link_click  === undefined || input.link_click === null",
        leafletOutput("Map", width = 1000, height = 500)

      ),


      conditionalPanel(
        condition <- "(input.link_click_Site  === undefined || input.link_click_Site === null) && (input.link_click  !== undefined && input.link_click !== null)",

        leafletOutput("CountryMap", width = 1000, height = 500)

      ),
      conditionalPanel(
        condition <- "(input.link_click_Site  !== undefined && input.link_click_Site !== null)",

        h3("Plots related to site chosen"),
        textOutput(outputId = "Check"),
        actionButton("Back", "Back")
      )
     ),
     tabItem(tabName = "widgets",
             h3("This is widget page")

             )
     )
  )
)


server <- function(input, output, session){
  Country = map("world", fill = TRUE, plot = FALSE, regions="USA")
  output$Map <- renderLeaflet({
    leaflet(Country) %>% addTiles() %>%  setView(0, 0,  zoom = 2)%>%
      #leaflet(target) %>% addTiles() %>%
      addPolygons(fillOpacity = 0.6,
                  fillColor = 'blue',
                  smoothFactor = 0.5, stroke = TRUE, weight = 1, popup =  paste("<b>", "USA", "</b><br>",
                                                                                actionLink(inputId = "View", 
                                                                                           label = "View Details", 
                                                                                           onclick = 'Shiny.onInputChange(\"link_click\",  Math.random())')))
  })

  output$CountryMap <- renderLeaflet({

    leaflet(Country) %>% addTiles() %>%   
      fitBounds(Country$range[1], Country$range[3], Country$range[2], Country$range[4])%>%
      addMarkers(lng = -71.03 , lat = 42.37, popup = paste("<b>", "Boston", "</b><br>",
                                                           actionLink(inputId = "View", 
                                                                      label = "View Details", 
                                                                      onclick = 'Shiny.onInputChange(\"link_click_Site\",  Math.random())')))
  })

  observeEvent(input$link_click_Site, {
    output$Check <- renderText("Success")

  })

  observeEvent({input$Back; input$mySidebar} , {
    session$sendCustomMessage(type = 'resetInputValue', message = "link_click_Site")
    session$sendCustomMessage(type = 'resetInputValue', message = "link_click")
  })

}


shinyApp(ui =ui, server = server)