R 使用 checkboxInput 切换图形

如果需要复选框的值，则必须使用input[["checkbox]]或input$checkbox引用它.

我想当下拉列表为"first"时，您需要一个黑色块，当下拉列表为"second"时，您需要一个蓝色/红色块(取决于复选框)？

Select 第一项时，解决方案将禁用该复选框.为此，您可以使用shinyjs包中的函数enabled/disabled.为此，我们必须在ui中初始化shinyjs.

library(shiny)
library(shinyjs)

mytest <- c("first","second")
# Define UI for application that draws a histogram
ui <- fluidPage(
  useShinyjs(), # to initialise shinyjs
  
  # Application title
  titlePanel("Old Faithful Geyser Data"),
  
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = "test",
                  label = "Test",
                  choices = mytest,
                  selected = "first"),
      disabled( # start as disabled
        checkboxInput("checkbox","check this box", FALSE))
      ),
    
    mainPanel(
      plotOutput("distPlot")
    )))


server <- function(input, output) {
  
  output$distPlot <- renderPlot({
    switch(
      input$test,
      "first" = { 
        plot(rnorm(100))
        disable("checkbox")
      },
      {
        enable("checkbox")
        if(input[["checkbox"]] == FALSE){
         "second" = plot(rnorm(1000), col="blue")
        } else{
         "second" = plot(rnorm(10000), col="red")   
        }
      }
    )
  })
}

shinyApp(ui = ui, server = server)