如何手动更改 R Shiny 中单选按钮的选定值？

Question

我有一个带有单选按钮的 R Shiny UI 组件，并且想手动更改代码中选定的值。

假设有 3 个值：“留在此处”、“执行”和“离开”。通过选择“Do it”，用户会看到操作按钮“Do it”。我想在用户单击操作按钮“Do it”后更改“stay_here”上选定的单选按钮值。这是代码。

library(shiny)

# UI
ui <- fluidPage(
  fluidPage(
    fluidRow(uiOutput("rbtn_test")),
    fluidRow(uiOutput("uo_stay_here")),
    fluidRow(uiOutput("uo_do_it")),
    fluidRow(uiOutput("uo_go_away"))))

# SERVER
server <- function(input, output) {
   
   # 1. Radio buttons
   output$rbtn_test <- renderUI({
     
     # 1.1. Values
     actions_values <- c("stay_here", "do_it", "go_away")
     names(actions_values) <- c("Stay here", "Do it", "Go away")
     
     # 1.2. Selected value
     action_selected <- "stay_here"
     
     # 1.3. UI element
     radioButtons(
       "rbtn_test_selected", "Actions", 
       choices = actions_values, 
       selected = action_selected, 
       inline = TRUE)
   })
   
   # 2. 'Stay here'
   output$uo_stay_here <- renderUI({
     if(input$rbtn_test_selected == "stay_here") {
       tags$div(tags$p("Stay here ..."))
     }
   })
   
   # 3. Process 'Do it' action
   output$uo_do_it <- renderUI({
     
     if(input$rbtn_test_selected == "do_it") {
       actionButton("btn_doit", "Do it")
       # TBD: Change selected value in radio buttons on 'stay_here'
     }
     
   })
   
   # 4. 'Go away'
   output$uo_go_away <- renderUI({
     if(input$rbtn_test_selected == "go_away") {
       tags$div(tags$p("Go away ..."))
     }
   })
   
   
}

# Run the application 
shinyApp(ui = ui, server = server)

谢谢！

Answer 1

您可以添加一个observeEvent“执行”操作按钮，该按钮将在单击时更改所选值。

 observeEvent(input$btn_doit, {
    updateRadioButtons(session, "rbtn_test_selected", selected = "stay_here")
  })

完整代码-

library(shiny)

# UI
ui <- fluidPage(
  fluidPage(
    fluidRow(uiOutput("rbtn_test")),
    fluidRow(uiOutput("uo_stay_here")),
    fluidRow(uiOutput("uo_do_it")),
    fluidRow(uiOutput("uo_go_away"))))

# SERVER
server <- function(input, output, session) {
  
  # 1. Radio buttons
  output$rbtn_test <- renderUI({
    
    # 1.1. Values
    actions_values <- c("stay_here", "do_it", "go_away")
    names(actions_values) <- c("Stay here", "Do it", "Go away")
    
    # 1.2. Selected value
    action_selected <- "stay_here"
    
    # 1.3. UI element
    radioButtons(
      "rbtn_test_selected", "Actions", 
      choices = actions_values, 
      selected = action_selected, 
      inline = TRUE)
  })
  
  # 2. 'Stay here'
  output$uo_stay_here <- renderUI({
    if(input$rbtn_test_selected == "stay_here") {
      tags$div(tags$p("Stay here ..."))
    }
  })
  
  # 3. Process 'Do it' action
  output$uo_do_it <- renderUI({
    
    if(input$rbtn_test_selected == "do_it") {
      actionButton("btn_doit", "Do it")
    }
  })
  
  observeEvent(input$btn_doit, {
    updateRadioButtons(session, "rbtn_test_selected", selected = "stay_here")
  })
  
  # 4. 'Go away'
  output$uo_go_away <- renderUI({
    if(input$rbtn_test_selected == "go_away") {
      tags$div(tags$p("Go away ..."))
    }
  })
  
  
}

# Run the application 
shinyApp(ui = ui, server = server)