r - 更新一个观察者中的多个单选按钮仅适用于第一个单选按钮

Question

我完全困惑为什么有两行工作代码(单独)，将各自的单选按钮重置为空(selected = character(0)) 仅在放在 1 个“观察者”内时重置第一行

这是最小的例子:

library(shiny)
library(shinyjs)

ui <- fluidPage(
  useShinyjs(),
  tags$script("
    Shiny.addCustomMessageHandler('resetValue', function(variableName) {
                  Shiny.onInputChange(variableName, null);
                  });
                  "),
  radioButtons("radio","Click Me",choices  = c("Choice 1","Choice s"),selected = character(0)),
  radioButtons("radio2","Click Me",choices  = c("Choice 1","Choice s"),selected = character(0)),
  actionButton("clickMe","Click Me to Reset"),
  actionButton("showValue", "Show value")
)

server <- function(input, output, session) {
  observeEvent(input$clickMe,{
    session$sendCustomMessage(type = "resetValue", message ='radio')
    updateRadioButtons(session,"radio",choices  = c("Choice 1","Choice s"),selected = character(0))
    session$sendCustomMessage(type = "resetValue", message ='radio2')

    updateRadioButtons(session,"radio2",choices  = c("Choice 1","Choice s"),selected = character(0))

  })

  observeEvent(input$showValue, {
    print(input$radio)
    print(input$radio2)
  })
}

shinyApp(ui, server)

其中sendcustomMessages用于重置值，这不是通过选择character(0)来实现的>，来自即 here

Answer 1

更新

我无法弄清楚为什么无法在一个reactiveEvent中更新两个radioButton，但该错误似乎源于将selected =参数设置为character(0) 。虽然第一个 updateRadioButtons 可与 character(0) 配合使用，但第二个则不能。

将 updateRadioButtons 的 selected = 参数中的 character(0) 更改为 0 会产生所需的结果并且以某种方式不会导致所述问题/错误。比较按钮值，最初将按钮设置为 character(0) 或 0 似乎没有区别。这两种方式的按钮值都是NULL。使用自定义 JavaScript 函数重置值后，JS 中的值将更新为 null。

library(shiny)
library(shinyjs)

ui <- fluidPage(
  useShinyjs(),
  tags$script("
              Shiny.addCustomMessageHandler('resetValue', function(variableName) {
              Shiny.onInputChange(variableName, null);
              });
              "),
  radioButtons("radio","Click Me",choices  = c("Choice 1","Choice s"),selected = character(0)),
  radioButtons("radio2","Click Me",choices  = c("Choice 1","Choice s"),selected = character(0)),
  actionButton("clickMe","Click Me to Reset"),
  actionButton("showValue", "Show value")
  )

server <- function(input, output, session) {
  observeEvent(input$clickMe,{
    session$sendCustomMessage(type = "resetValue", message ='radio')
    updateRadioButtons(session,"radio",choices  = c("Choice 1","Choice s"),selected = 0)
    session$sendCustomMessage(type = "resetValue", message ='radio2')

    updateRadioButtons(session,"radio2",choices  = c("Choice 1","Choice s"),selected = 0)

  })

  observeEvent(input$showValue, {
    print(input$radio)
    print(input$radio2)
  })
}

shinyApp(ui, server)