带有单选按钮流程图的闪亮应用程序，如何前进/返回

Question

我写了一个闪亮的应用程序，可以向用户显示不同的单选按钮。根据输入，数字将添加到

score/counter

和其他单选按钮将弹出（和前一个将被禁用）。

我现在想知道，我如何实现一个“后退”按钮，让用户后退一步（例如，在误点击的情况下）这意味着：

1. 隐藏最近的单选按钮
2. 再次激活最后一个单选按钮
3. 调整

   score/counter

我学会了如何添加一个调用

session$reload()

的“重置”按钮，它会删除所有内容，用户可以重新开始。但是，如果用户可以返回一步就更好了。

例子：

ui.R

ui <- fluidPage(
  
  shinyjs::useShinyjs(),
  # Add an invisible counter to store the total score
  verbatimTextOutput(outputId = "counter", placeholder = TRUE),
  
  # Add a radio button with two choices
  radioButtons(inputId = "a",
               # label = "a",
               label = "a",
               choices = c("10", "5"),
               selected = ""),
  
  
  # UI elements for the b and c radio buttons
  uiOutput("b"),
  uiOutput("c"),
  uiOutput("d"),
  uiOutput("c1"),
  uiOutput("e"),
  uiOutput("f"),
  
  # Add a back button to allow the user to go back to the previous question
  actionButton(
    inputId = "reset_button",
    label = "Reset",
    width = "50%"
  ),
  textOutput("reset_val")
  
)

服务器.R

server <- function(input, output, session) {
  
  reset_rv <- reactiveVal(value = 0L)
  
  
  
  # Initialize the counter to 0
  counter <- reactiveValues(value = 0)
  
  # Track the selected options
  selected_options <- reactiveValues(
    a = NULL,
    b = NULL,
    d = NULL,
    c = NULL,
    e = NULL,
    f = NULL
  )
  
  # Update the counter when the a radio button is clicked
  observeEvent(input$a, {
    if (!is.null(input$a)) {
      selected_options$a <- input$a
      if (input$a == "5") {
        counter$value <- counter$value + 0
        output$b <- renderUI({
          radioButtons(inputId = "b",
                       label = "b",
                       choices = c("a", "10"),
                       selected = "")
        })
        
      } else if (input$a == "10") {
        counter$value <- counter$value + 8
        output$c <- renderUI({
          radioButtons(inputId = "c",
                       label = "c",
                       choices = c("L", "R"),
                       selected = "")
        })
    
        
        }}
    shinyjs::disable("a")
    })

  

# 2 -----------------------------------------------------------------------

  observeEvent(input$b, { 
    if (!is.null(input$b)) {
      selected_options$b <- input$b
      if (input$b == "5") {
        counter$value <- counter$value + 0
        output$d <- renderUI({
          radioButtons(inputId = "d",
                       label = "d",
                       choices = c("5", "10"),
                       selected = "")
        })
      } else if (input$b == "10") {
        counter$value <- counter$value + 6
        output$c1 <- renderUI({
          radioButtons(inputId = "c1",
                       label = "c",
                       choices = c("L", "R"),
                       selected = "")})}}
    shinyjs::disable("a")
    shinyjs::disable("b")
    })
  
    
  
  observeEvent(input$c, {
    if (!is.null(input$c)) {
      selected_options$c <- input$c
      if (input$c == "R") {
        counter$value <- counter$value + 0
        output$e <- renderUI({
          radioButtons(inputId = "e",
                       label = "e",
                       choices = c("5", "10"),
                       selected = "")
        })
      } else if (input$c == "L") {
        counter$value <- counter$value + 4
        output$f <- renderUI({
          radioButtons(inputId = "f",
                       label = "L",
                       choices = c("5", "10"),
                       selected = "")})}}
    
    shinyjs::disable("a")
    shinyjs::disable("c")
    })    
  
  
  
  # Update the counter output
  output$counter <- renderText({
    paste("Score:", counter$value)
  })
  
  observeEvent(input$reset_button, {
    reset_rv(input$reset_button)
    session$reload()
  })
  

  
}



 
  

奔跑

shinyApp(ui = ui, server = server)