使conditionalPanel在R闪亮的Golem包中使用输入参数

Question

我通常会看到conditionalPanel在事件发生时工作，比如按下按钮或选中复选框等，但在这里，我希望它能够在运行应用程序时传递一个参数。只有当“输入”参数不是null时，我才会试图显示条件面板，但是面板总是会出现。下面是我尝试过的代码：

app_ui.R

#' The application User-Interface
#'
#' @param request Internal parameter for `{shiny}`.
#'     DO NOT REMOVE.
#' @import shiny
#' @noRd
app_ui <- function(request) {
  tagList(
    # Leave this function for adding external resources
    golem_add_external_resources(),
    # List the first level UI elements here
    fluidPage(
      h1("testapp"),
      conditionalPanel(
        condition = "!is.null(r.input)",
        p('there is an input ')

      )
    )
  )
}

app_server.R

#' The application server-side
#'
#' @param input,output,session Internal parameters for {shiny}.
#'     DO NOT REMOVE.
#' @import shiny
#' @noRd
app_server <- function( input, output, session ) {
  # List the first level callModules here
  r <- reactiveValues(query = reactiveValues())

  observe({
    input <- golem::get_golem_options("input")
    r$input <- input

  })
}

run_app.R

#' Run the Shiny Application
#'
#' @param input input
#'
#' @export
#' @importFrom shiny shinyApp
#' @importFrom golem with_golem_options
run_app <- function(
  input = NULL
) {
  with_golem_options(
    app = shinyApp(
      ui = app_ui,
      server = app_server
    ),
    golem_opts = list(input = input)
  )
}

Answer 1

get_golem_options("input")的优点在于它也可以在您的UI中使用:)

所以我认为你可以做一些更简单的事情，比如：

app_ui <- function(request) {
  tagList(
    # Leave this function for adding external resources
    golem_add_external_resources(),
    # List the first level UI elements here
    fluidPage(
      h1("testapp"),
      if (!is.null(golem::get_golem_options("input")){
          your_UI_here(...)
      }
    )
  )
}