Shining updateSliderInput：将双端滑块转换为单端滑块

我有一个双端闪亮滑块输入，如下所示：

sliderInput(inputId = "years",
                             label="Choose base year and target year",
                             min = 2015,
                             max = 2060,
                             value = c(2015,2060),
                             step = 1,
                             sep = ""
                 )

在用户上传一个值后，我想将滑块的下端固定到某个值；上端仍应可移动。我试图通过使用updateSliderInput函数来实现这一点，并且只为“value”属性提供一个值（因此，滑块应该成为常规的单端滑块）：

然而，这是行不通的；滑块仍然是双端的，两个控制柄都设置为2060。如何将双端滑块转换为常规滑块

亲切问候,

---

Requin

这里有另一个更接近您的问题的解决方案，按下按钮后仅触发一次：

library(shiny)

ui <- fluidPage(
  uiOutput("Slider_UI"),
  conditionalPanel("input.fixLower == 0", {actionButton("fixLower", "Fix lower range")})
)

server <- function(input, output, session) {

  fixedLower <- reactiveVal()

  observeEvent(input$fixLower, {
    fixedLower(min(isolate({input$years})))
  }, once = TRUE)

  output$Slider_UI <- renderUI({
    if(is.null(fixedLower())){
      sliderInput(inputId = "years",
                  label="Choose base year and target year",
                  min = 2015,
                  max = 2060,
                  value = c(2015, 2060),
                  step = 1,
                  sep = ""
      )
    } else {
      sliderInput(inputId = "years",
                  label="Choose base year and target year",
                  min = fixedLower(),
                  max = 2060,
                  value = fixedLower(),
                  step = 1,
                  sep = ""
      )
    }
  })

}

shinyApp(ui = ui, server = server)

---

下面是另一个更接近您的问题的解决方案，按下按钮后仅触发一次：

library(shiny)

ui <- fluidPage(
  uiOutput("Slider_UI"),
  conditionalPanel("input.fixLower == 0", {actionButton("fixLower", "Fix lower range")})
)

server <- function(input, output, session) {

  fixedLower <- reactiveVal()

  observeEvent(input$fixLower, {
    fixedLower(min(isolate({input$years})))
  }, once = TRUE)

  output$Slider_UI <- renderUI({
    if(is.null(fixedLower())){
      sliderInput(inputId = "years",
                  label="Choose base year and target year",
                  min = 2015,
                  max = 2060,
                  value = c(2015, 2060),
                  step = 1,
                  sep = ""
      )
    } else {
      sliderInput(inputId = "years",
                  label="Choose base year and target year",
                  min = fixedLower(),
                  max = 2060,
                  value = fixedLower(),
                  step = 1,
                  sep = ""
      )
    }
  })

}

shinyApp(ui = ui, server = server)

---

您使用

renderUI

和“uiOutput”归档该文件是否有效？可能也有兴趣。使用

renderUI

和“uiOutput”来归档是否有效？可能也有兴趣。很好的解决方案。OP，如果您想保留这些值，请考虑使用

reactiveValues

good solution存储它们。OP，如果您想保留这些值，请考虑使用

reactiveValues

library(shiny)

ui <- fluidPage(
  radioButtons(inputId="type_select", label="Select slider type", choices = list("Standard slider", "Range slider")),
  uiOutput("Slider_UI")
)

server <- function(input, output, session) {

  output$Slider_UI <- renderUI({
    req(input$type_select)

    if(input$type_select == "Range slider"){
      presetValues <- c(2015, 2060)
    } else {
      presetValues <- 2060
    }

    sliderInput(inputId = "years",
                label="Choose base year and target year",
                min = 2015,
                max = 2060,
                value = presetValues,
                step = 1,
                sep = ""
    )
  })

}

shinyApp(ui = ui, server = server)