动作按钮和observeEvent不起作用（R闪亮）

Question

Can somebody check the code below for me and tell me what's wrong?

shinyUI(fluidPage(
    sidebarLayout(
    sidebarPanel(
        sliderInput("Mean",
        label="Drag to select the mean of the normal distribution",
        min=0,max=5,value=0),
        actionButton("show","Go")
    ),
    mainPanel(
                h3("The number is"),
                textOutput('number')
    )   
  )
))

shinyServer(function(input, output) {

    #observeEvent(input$show, {
        #output$number <- round(rnorm(as.numeric(input$mu)), 2)
     #}) 

    output$number <- eventReactive(input$show, {
        round(rnorm(as.numeric(input$mu)), 2)
    })
    }
)

Just want to have a random number sampled from a normal distribution with a given mean each time I click 'Go'. Neither eventReactive nor observeEvent worked.

Answer 1

I'n not a big fan of having objects inside observeEvent so here is the solution with eventReactive

library(shiny)
ui <- shinyUI(fluidPage(
  sidebarLayout(
    sidebarPanel(
      sliderInput("Mean",label="Drag to select the mean of the normal distribution",min=0,max=5,value=0),
      actionButton("show","Go")
    ),
    mainPanel(
      h3("The number is"),
      textOutput('number')
    )   
  )
))

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

  data <- eventReactive(input$show, {
    round(rnorm(as.numeric(input$Mean)), 2)
  })

  output$number <- renderText({
    data()
  })

}
)
shinyApp(ui, server)

Answer 2

The output of eventReactive is a reactive variable. You will need to use renderText and observeEvent . Also you have not defined input$mu in your ui, I think it should be input$Mean

After implementing the above modifications your server code should be something like this:

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

           observeEvent(input$show, {
           output$number <- renderText(round(rnorm(as.numeric(input$Mean)), 2))
           })

         }
         )

Hope it helps!