Question

我正在构建一个Shiny应用程序，它根据selectInput（）值更新checkboxGroupInput（）。我还想存储选择/取消选择的值，以便每当我重新选择输入值时它们将显示为相同。为此，我使用反应值来存储选择。

这是一个玩具示例：

library(shiny)

letters = c('A','B','C','D','E','F','G','H','I','J','K','L')

words = list( "A" = c("apples","aardvark","alabama"),
              "B" = c("banana","baltimore","beehive"),
              "C" = c("catastrophe","cantalope"),
              "D" = c("dinosaur","dairy","dolphin"),
              "E" = c("eager","elephant","ecumenical"),
              "F" = c("fleming","florida","flight"),
              "G" = c("gator","greater","gait"),
              "H" = c("HI"),
              "I" = c("igloo","ignominious","interesting"),
              "J" = c("jogging","jumpsuit"),
              "K" = c("kellog","kangaroo"),
              "L" = c("lemon","lime","lemonjello"))


ui <- fluidPage(

    selectInput("letter","Choose Letter",choices=letters,selectize=F), 

  # Initiate check box group
    checkboxGroupInput('words_by_letter',label='Select Your Favorite Words',choices = c(1))

)


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

  v_selected <- reactiveValues(
        "A" = c("apples","aardvark","alabama"),
        "B" = c("banana","baltimore","beehive"),
        "C" = c("catastrophe","cantalope"),
        "D" = c("dinosaur","dairy","dolphin"),
        "E" = c("eager","elephant","ecumenical"),
        "F" = c("fleming","florida","flight"),
        "G" = c("gator","greater","gait"),
        "H" = c("HI"),
        "I" = c("igloo","ignominious","interesting"),
        "J" = c("jogging","jumpsuit"),
        "K" = c("kellog","kangaroo"),
        "L" = c("lemon","lime","lemonjello"))

  observeEvent(input$letter,{         
    updateCheckboxGroupInput(session,
       inputId  = "words_by_letter",
       choices  = words[[input$letter]], 
       selected = v_selected[[input$letter]])

  })

  observeEvent(input$words_by_letter,{ 
    v_selected[[input$letter]] = input$words_by_letter
  })

}


shinyApp(ui = ui, server = server)

在大多数情况下，这很好用。但是，如果您快速滚动输入（通过按住箭头按钮），最终将取消选中某些复选框组。我假设这与反应速度和与Javascript的沟通有关，但我不知道如何解决它。

注意：我也尝试为每个'字母'使用单独的conditionalPanel，但这会大大增加我的应用程序的加载时间，所以我不想使用该策略。 / p>

Answer 1

这似乎是竞争条件，input$letter的更新速度太快，以至于shinyServer无法跟上并尝试使用不一致的数据更新反应状态。例如，它使用“J”选项来修改和覆盖“I”字，然后输入选择器不再起作用。我不认为根本原因很容易解决。

但是，解决方法是仅在input$letter和input$words_by_letter中的值保持一致时才更新您的被动状态。

根据您的实际数据，这可能会或可能不会起作用 - 您需要组织数据，以便存在可以测试的一致性条件，并使用它来保护您的更新。在你的玩具示例中，我可以将选择的单词与初始化选择的单词进行比较 - 我利用了它。

我本可以比较匹配input$words_by_letter的{{1}}中单词的第一个字母，但这看起来太专业了 - 这样，将所选数据与选择初始化进行比较更有可能推广。

以下是代码：

input$letter

对于它的价值，这就是应用程序的样子：

使用updateCheckboxGroupInput（）和selectinput（）的R Shiny缓存值

1 个答案: