Shiny Dashboard：在不同的Tabitem中導航時，重置條件面板狀態

Question

我有以下代碼，其中儀表板上有各種條件面板。 如果我們從一個條件面板導航到儀表板中的下一個，然后轉到小部件，最后返回儀表板，則該儀表板處於先前狀態。 當我從另一個選項卡面板返回時，我希望儀表板刷新（重置為原始狀態）。 有可能這樣做嗎？

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

每當切換面板時，都可以使用與單擊“后退”按鈕時重置視圖相同的代碼來重置視圖。

您只需為側邊欄提供一個id ，然后您就可以收聽此ID的輸入，它告訴您哪個面板處於活動狀態。 下面的解決方案是一個最小的解決方案，僅增加了兩個： sidebarMenu獲取一個輸入id， id = "mySidebar" ，而observeEvent觀察第二個變量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)