Question

我正在使用shiny，使用conditionalPanel时我很难让R识别输入。我的应用程序中有两个这样的面板，因为我需要它们根据用户选择哪个单选按钮来生成特定列表。

从UI角度来看，一切都可以正常显示，但是由于某些原因，即使在字段中输入了“名称”选项，R仍无法拾取任何输入。使用了正确的列表，但是由于某种原因，它没有检测到任何输入。这是选择和结果的屏幕截图。

如果我从单选按钮中选择另一个选项并输入一个项目，则没有问题-它可以按预期工作。这是我正在使用的代码。

ui <- fluidPage(
         sidebarPanel(
             # the user can choose from two options within the radio buttons
             radioButtons("items_type", label = "Choose items for analysis"
                           , choices = list("Items - Item number & name" = "Both",  "Items - Item name only" = "Name")
                           , selected = "Both")
             # if the 'Both' option is selected, the items_list_names_id option is used
             , conditionalPanel(
                                condition = "output.items_type == 'Both'"
                               , selectInput("items", label = NULL, choices = items_list_names_id, multiple = TRUE))
            # if the 'Name' option is selected, the items_list_names option is used. input 
            # is not being detected here for some reason, and I'm wondering if it's because 
            # I use "items" for both selectInputs
            , conditionalPanel(
                                condition = "output.items_type == 'Name'"
                               , selectInput("items", label = NULL, choices = items_list_names, multiple = TRUE))

            # action button so the user can submit for analysis based on their selected options
            , actionButton("go", "Run", style = "color: white; background-color: #2759aa")
     )
  )



server <- function(input, output){

  # this portion is used to detect if the user alternates between either option from the radio buttons and uses the appropriate selectInput option
  output$items_type <- reactive({
     input$items_type
  })

  outputOptions(output, "items_type", suspendWhenHidden = FALSE)  

Results <- eventReactive(input$go, {

    # this portion is simply for testing for me to see how R recognizes the inputs
    observe({print(input$items_type)})
    observe({print(input$items)})

    # checks to make sure the user selects at least 1 item. For some reason,
    # this portion is triggered when at least 1 item is selected under the 'Name' 
    # condition from the conditional panel.
    validate(
        need(input$items > 0, 'Please select at least 1 item for analysis')
       ) 

#other steps start here, but the above is the more pertinent part
}

编辑：因此，似乎两个selectInput选项都具有相同的输入ID，这就是R在条件面板之间切换时无法识别输入的原因。但是，最好有一个输入ID，因为在我的代码的其他部分（未在上面显示）中使用了intput$item。重写代码，使其使用例如两个变量input$item1和input$item2，因为每种情况都可能非常麻烦。我愿意提出任何避免这种情况的建议。

编辑2 ：我当时在想也许只使用一个conditonalPanel并根据用户的选择使用switch语句在两个列表之间进行切换。从理论上讲，这应该是可行的，并且在不修改我所有其他代码的情况下将是一个方便的解决方案。看起来像这样：

  , conditionalPanel(
    condition = "output.items_list_selection"
    , selectInput("items", label = 'Select items'
                  , choices = switch("output.items_list_selection", "Both" = items_list_names_id, "Name" = items_list_names)
                  , multiple = TRUE))

但是没有出现下拉菜单，因为该修订本应该如此。

Answer 1

一种可能的解决方案是使用updateSelectInput，因此两个具有相同di inputId的id没问题

library(shiny)

items_list_names_id = c("id1", "id2")
items_list_names = c('name1', 'name2')

ui <- fluidPage(
  sidebarPanel(
    # the user can choose from two options within the radio buttons
    radioButtons("items_type", label = "Choose items for analysis"
                 , choices = list("Items - Item number & name" = "Both",  "Items - Item name only" = "Name")
                 , selected = "Both"),
    # if the 'Both' option is selected, the items_list_names_id option is used
    selectInput("items", label = NULL, choices =  c('init'), multiple = TRUE),

    # action button so the user can submit for analysis based on their selected options
    actionButton("go", "Run", style = "color: white; background-color: #2759aa")
  )
)



server <- function(input, output, session){
  # change the choices depending on the value of input$intems_type
  observeEvent(input$items_type, {
    if(input$items_type == 'Both'){
      updateSelectInput(session, 'items', label = NULL, choices = items_list_names)
    }
    if(input$items_type == 'Name'){
      updateSelectInput(session, 'items', label = NULL, choices = items_list_names_id)
    }
  })

  # check if it's working
  observeEvent(input$go,{
    print(input$items)
    print(input$items_type)
  })

}

shinyApp(ui, server)

闪亮-条件面板无法识别输入

1 个答案: