反应性地更新 Shiny 中的滑块输入

Question

我正在尝试从sliderInput动态更改值。现在的困难是我想从sliderInput一个值变成sliderInput一个范围，这似乎不起作用。

下面代码中的第一个 actionbutton 有效，而第二个却没有它的意图。

是切换到uiOutput元素的唯一可能性吗？

代码

library(shiny)
app <- shinyApp(
   ui = bootstrapPage(
      sliderInput("sld1", min = 0, max = 10, label = "y1", value = 5),
      actionButton("acb1", "Change Value"),
      actionButton("acb2", "Change Value to Range")
   ),
   server = function(input, output, session) {
      observeEvent(input$acb1, {
         updateSliderInput(session, "sld1", value = 2)
      })
      observeEvent(input$acb2, {
         updateSliderInput(session, "sld1", value = c(2,7))
      })
   })
runApp(app)

Answer 1

您可以使用动态添加滑块 renderUI

#rm(list = ls())
library(shiny)
app <- shinyApp(
  ui = bootstrapPage(
    uiOutput("myList"),
    actionButton("acb1", "Change Value"),
    actionButton("acb2", "Change Value to Range")
  ),
  server = function(input, output, session) {

    slidertype <- reactiveValues()
    slidertype$type <- "default"

    observeEvent(input$acb1,{slidertype$type <- "normal"})
    observeEvent(input$acb2, {slidertype$type <- "range"})

    output$myList <- renderUI({

      if(slidertype$type == "normal"){
        sliderInput("sld1", min = 0, max = 10, label = "y1", value = 2)
      }
      else if(slidertype$type == "range"){
        sliderInput("sld1", min = 0, max = 10, label = "y1", value = c(2,7))
      }
      else{
        sliderInput("sld1", min = 0, max = 10, label = "y1", value = 5)
      }
    })    
})
runApp(app)