如何将 insertUI() 输出添加到 R Shiny 中的 renderText() 输出？

Posted 2023-04-18

【中文标题】如何将 insertUI() 输出添加到 R Shiny 中的 renderText() 输出？

【英文标题】：How do I add insertUI() output to renderText() ouput in R Shiny?

【发布时间】：2018-02-28 21:47:35

【问题描述】：

我正在开发一个闪亮的应用程序来为系统开发提供自动化，我需要一种方法来为用户输入添加文本框，并将生成的用户输入添加到 renderText() 输出。我不确定是否有办法遍历反应值，所以现在我不得不对 textInput() 结果中的标签进行特定调用。代码如下，注意需要修改的部分是 server 部分底部的 output$value 部分：

library(shiny)
ui <- fluidPage(
            fluidRow(
                column(6,
                    textInput("mainDesc1", label = "Main Description", value = "", width = '100%')
                    ),
                column(1,
                    actionButton(inputId = 'insertBtn', label = "More")
                    ),
                column(1,
                    actionButton(inputId = 'removeBtn', label = "Less")
                    )
                ),
            tags$div(id = 'placeholder'),
            fluidRow(column(12, verbatimTextOutput("value")))
)

server <- function(input, output) 
    ## keep track of elements inserted and not yet removed
    inserted <- c()
    #btn <- 1
    observeEvent(input$insertBtn, 
        btn <- input$insertBtn + 1
        id <- paste0("mainDesc", btn)
        insertUI(
            selector = '#placeholder',
        ## wrap element in a div with id for ease of removal
            ui = tags$div(
                tags$p(fluidRow(
                    column(6,
                        textInput(paste("mainDesc", btn + 1, sep = ""), label = "", value = "", width = '100%')
                        )
                    )
                ),
                id = id
                )
            )
        inserted <<- c(id, inserted)
    )

    observeEvent(input$removeBtn, 
        removeUI(
        ## pass in appropriate div id
          selector = paste0('#', inserted[length(inserted)])
        )
        inserted <<- inserted[-length(inserted)]
    )

    output$value <- renderText( noquote(paste(input[[paste("mainDesc", 1, sep = "")]], "\n",
                                               input[[paste("mainDesc", btn + 1, sep = "")]], sep = ""))
                                               )
    
shinyApp(ui = ui, server = server)

如何循环遍历由于以下原因而弹出的 userInput() 框的结果

textInput(paste("mainDesc", btn + 1, sep = ""), label = "", value = "", width = '100%')

逐行粘贴上述所有现有输出？本质上，我正在寻找的是如果用户在第一个“主要描述”文本框中输入“第一行”，单击“更多”按钮在弹出的文本框中添加“第二行”，再次单击更多并在 renderText() 框输出的弹出文本框中输入“第 3 行”：

1st line
2nd line
3rd line

如果添加了更多文本框，则应将用户输入逐行添加到 renderText() 输出中。谢谢！

【参考方案1】：

试着把btn变成reactiveValue：

vals <- reactiveValues(btn = 1)
# reference elsewhere in your app as vals$btn

在这里查看似乎有效的代码：

library(shiny)

ui <- fluidPage(
  fluidRow(
    column(6,
           textInput("mainDesc1", label = "Main Description", value = "", width = '100%')
    ),
    column(1,
           actionButton(inputId = 'insertBtn', label = "More")
    ),
    column(1,
           actionButton(inputId = 'removeBtn', label = "Less")
    )
  ),
  tags$div(id = 'placeholder'),
  fluidRow(column(12, verbatimTextOutput("value", placeholder = T)))
)

server <- function(input, output) 
  ## keep track of elements inserted and not yet removed
  vals <- reactiveValues(btn = 0)

  observeEvent(input$insertBtn, 
    vals$btn <- vals$btn + 1
    insertUI(
      selector = '#placeholder',
      ## wrap element in a div with id for ease of removal
      ui = tags$div(
        id = paste0('line', vals$btn),
        tags$p(fluidRow(
          column(6,
                 textInput(paste("mainDesc", vals$btn + 1, sep = ""), label = paste("Line", vals$btn), value = "", width = '100%')
                 )
          )
        )
      )
    )
  )

  observeEvent(input$removeBtn, 
    removeUI(
      ## pass in appropriate div id
      selector = paste0('#line', vals$btn)
    )
    vals$btn <- vals$btn - 1
  )

  output$value <- renderText( 
    msg <- c(input[["mainDesc1"]])
    if (vals$btn > 0) 
      for (i in 1:vals$btn) 
        msg <- c(msg, input[[paste0("mainDesc", i + 1)]])
      
      msg <- paste(msg, collapse = "\n")  
    
  )


shinyApp(ui = ui, server = server)