闪亮：根据索引动态添加/删除textInput行

Question

根据本文，我更改了脚本：

library(shiny)

ui = fluidPage( 
  actionButton("add", "Add new Row", icon=icon("plus", class=NULL, lib="font-awesome")),
  actionButton("remove", "Remove last Row", icon=icon("times", class = NULL, lib = "font-awesome")),
  tags$div(id = 'placeholder')
)

server = function(input, output) {

  ## keep track of elements inserted and not yet removed
  inserted <- c()

  observeEvent(input$add, {
    id <- ''
    insertUI(
      selector = "#placeholder",
      where = "beforeBegin",
      ui =tags$div(
        id = id,
        fluidRow(
          column(2,
                 textInput("alias", label = h5("first"))
          ),
          column(2,
                 textInput("pop", label = h5("second"))
          ),
          column(2,
                 textInput("parent", label = h5("third"))
          ),
          column(2,
                 textInput("dims", label = h5("fifth"))
          ),
          column(2,
                 textInput("method", label = h5("fourth"))
          ),
          column(2,
                 textInput("args", label = h5("sixth"))
          )
        ) 
      )
    )

    inserted <<- c(inserted, id)

  })

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

    inserted <<- inserted[-length(inserted)]
  })

}

shinyApp(ui = ui, server = server)

我调查了这个问题，但比以前更加困惑。 add按钮可以正常工作，但是在单击remove按钮时行不会消失。 我究竟做错了什么？

谢谢！

Answer 1

除了分配ID，您还很亲密。 您忘记设置ID了吗？ 我看到的唯一分配是： id <- '' 。 另外，您应该使用reactiveValues()而不是闪亮的全局变量。

请参见下面的改编代码：

library(shiny)

ui = fluidPage( 
  actionButton("add", "Add new Row", icon=icon("plus", class=NULL, lib="font-awesome")),
  actionButton("remove", "Remove last Row", icon=icon("times", class = NULL, lib = "font-awesome")),
  tags$div(id = 'placeholder')
)

server = function(input, output) {

  ## keep track of elements inserted and not yet removed
  inserted <- reactiveValues(val = 0)

  observeEvent(input$add, {
    id <- length(inserted$val) + 1
    insertUI(
      selector = "#placeholder",
      where = "beforeBegin",
      ui =tags$div(
        id = id,
        fluidRow(
          column(2,
                 textInput("alias", label = h5("first"))
          ),
          column(2,
                 textInput("pop", label = h5("second"))
          ),
          column(2,
                 textInput("parent", label = h5("third"))
          ),
          column(2,
                 textInput("dims", label = h5("fifth"))
          ),
          column(2,
                 textInput("method", label = h5("fourth"))
          ),
          column(2,
                 textInput("args", label = h5("sixth"))
          )
        ) 
      )
    )
    inserted$val <- c(inserted$val, id)
    print(inserted$val)
  })

  observeEvent(input$remove,{
    print(inserted$val)
    removeUI(
      ## pass in appropriate div id
      selector = paste0('#', inserted$val[length(inserted$val)])
    )

    inserted$val <- inserted$val[-length(inserted$val)]
  })

}

shinyApp(ui = ui, server = server)