R，监视变量并更新ui

我正在尝试在一个闪亮的应用程序中创建一个消息系统，当某些任务完成时，它会收到通知，但目前它不起作用：

用户界面：

服务器：

library(shinydashboard)

shinyServer(function(input, output) {

  M_Store <- reactiveValues(DF = data.frame(
    from = c("Admininstrator", "New User", "Support"),
    message = c(
      "Sales are steady this month.",
      "How do I register?",
      "The new server is ready."
    ),
    stringsAsFactors = FALSE
  ))

  output$messageMenu <- renderMenu({
    msgs <- apply(M_Store$DF, 1, function(row) {
      messageItem(from = row[["from"]], message = row[["message"]])
    })
    dropdownMenu(type = "messages", .list = msgs)
  })

  reactive({
    input$go
    message("Button pressed. Execute analysis!")
    message("Pretend analysis got done!")
    message("Now want to send a message that the analysis is done!")
    M_Store$DF <- rbind(isolate(M_Store$DF), data.frame(from="Meee", message="Done message!"))
    })

  reactive({
    input$go2
    message("Second button pressed. Execute second analysis!")
    message("Some computation!")
    message("Want to update the user on progress with a message!")
    M_Store$DF <- rbind(isolate(M_Store$DF), data.frame(from="Someone else!", message="Progress message2!"))
    message("More computations....")
    message("Done, want to tell user I'm done!")
    M_Store$DF <- rbind(isolate(M_Store$DF), data.frame(from="Someone else!", message="Done message2!"))
  })
})

库（ShinydaShashboard）
shinyServer（功能（输入、输出）{
M_Store您可以将
reactiveValues
功能与
隔离功能结合使用。您的案例看起来像：

messageData <- data.frame(from = character(0),  message = character(0), stringsAsFactors = F) #simplified this a bit

shinyServer(function(input, output) {

  M_Store <- reactiveValues(DF = messageData)

  newMessage <- reactive(data.frame(from = as.character(input$from),message = as.character(input$message)))
  observe({
    M_Store$DF <- rbind(isolate(M_Store$DF), newMessage())
  })

  output$myUI <- renderUI({

   #some code
   ... M_Store$DF ...
   #some code

  })
})

每当
input$go
的值发生变化时（每次按下按钮时），就会触发该命令。如果您将其他输入值或响应值放在此处，您可以将其与其他流程或ui元素绑定
我尝试的是将其绑定，以便当有人执行某些操作时，例如加载数据或执行某些分析，在操作完成后，会将消息推送到messageData，并显示在ui中。将生成特定消息d当某个反应式表达式（例如依赖于输入的t检验）结束时。我刚刚编辑了问题，用一个玩具示例显示了我想要做的事情。（但不起作用）
messageData <- data.frame(from = character(0),  message = character(0), stringsAsFactors = F) #simplified this a bit

shinyServer(function(input, output) {

  M_Store <- reactiveValues(DF = messageData)

  newMessage <- reactive(data.frame(from = as.character(input$from),message = as.character(input$message)))
  observe({
    M_Store$DF <- rbind(isolate(M_Store$DF), newMessage())
  })

  output$myUI <- renderUI({

   #some code
   ... M_Store$DF ...
   #some code

  })
})

observeEvent(input$go,{
    message("Button pressed. Execute analysis!")
    message("Pretend analysis got done!")
    message("Now want to send a message that the analysis is done!")
    M_Store$DF <- rbind(isolate(M_Store$DF), data.frame(from="Meee", message="Done message!"))
  })