如何将加号和减号箭头添加到sliderInput（）中？

我正在开发一个闪亮的应用程序，希望提高滑块的精度（滑块范围从0到1000，很难用1的步长精确调整滑块）。我在任何地方都找不到答案。 这是我的一个滑块的代码：

sliderInput("mean2", "", min=0, max=1000, value=500, step=1)

---

试着像这样安排代码：

library(shiny)

ui <- fluidPage(

  # Application title
  titlePanel("Old Faithful Geyser Data"),
  actionButton("minus", "Minus"),
  actionButton("plus", "Plus"),
  # Sidebar with a slider input for number of bins
  sidebarLayout(
    sidebarPanel(
      sliderInput("mean2",
                  "Number of bins:",
                  min = 0,
                  max = 1000,
                  value = 500,
                  step= 1)
    ),

    # Show a plot of the generated distribution
    mainPanel(
      plotOutput("distPlot")
    )
  )
)

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

  v <- reactiveValues(data = 500)

  observeEvent(input$minus, {
    v$data <- input$mean2 - 1
    updateSliderInput(session,"mean2", value = input$mean2 - 1)
  })

  observeEvent(input$plus, {
    v$data <- input$mean2 + 1
    updateSliderInput(session,"mean2", value = input$mean2 + 1)
  })  

  observeEvent(input$mean2, {
    v$data <- input$mean2
  })

  output$distPlot <- renderPlot({

    # generate bins based on input$bins from ui.R
    x    <- faithful[, 2]
    bins <- seq(min(x), max(x), length.out = v$data + 1)

    # draw the histogram with the specified number of bins
    hist(x, breaks = bins, col = 'darkgray', border = 'white')

  })

}

shinyApp(ui, server)

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