Question

I have a problem with my shinyapp. I want to upload data for my calculations. When I do so the app automatically runs through the whole script the moment the upload is complete, so I implemented an action button. When I start the app and upload the data I have to click on the action button, the program executes and everything works fine. But when I start the app and click on the action Button first and then upload data, the program executes without having to click on the run button again. I made an example here. Because my actual app is ways bigger I need this feature that the programs is not executing automatically after uploading new data once the action button was clicked for the data I uploaded in the first place. I know that there is isolate() and I tried to implement it in every position possible but without any result. Can somebody help me out here? Here the code. with example data.

Mydata<-data.frame(A=1:1100,B=rnorm(1100, 50, 5))
write.csv(Mydata, file = "MyData.csv")

and the app:

ui <- fluidPage(
  titlePanel("Uploading Files"),
  sidebarLayout(
    sidebarPanel(
      fileInput('files1', 'Choose CSV File',
                accept=c('text/csv', 
                         'text/comma-separated-values,text/plain', 
                         '.csv'), multiple = TRUE),
      tags$hr(),

      radioButtons('sep', 'Separator',
                   c(Comma=',',
                     Semicolon=';',
                     Tab='\t'),
                   ','),
      actionButton("go","run",class = "btn-primary"),br()
    ),
    mainPanel(tags$head(tags$style(type="text/css", "
             #loadmessage {
                           position: fixed;
                           top: 95%;
                           left: 0px;
                           width: 100%;
                           padding: 5px 0px 5px 0px;
                           text-align: center;
                           font-weight: bold;
                           font-size: 100%;
                           color: #000000;
                           background-color: #CCFF66;
                           z-index: 105;
                           }
                           ")),
              conditionalPanel(condition="$('html').hasClass('shiny-busy')",
                               tags$div("Loading...",id="loadmessage")),
      verbatimTextOutput('text1')

      )
      )
  )


server <- function(input, output) {

observeEvent(input$go,{
  mapz <- reactive({
    inFiles <- input$files1

    if (is.null(inFiles))
      return(NULL)
    Q <- read.csv(input$files1[[1, 'datapath']],sep=input$sep,dec="." )
    names(Q)<-c("A","B")
    Q<-Q[Q$A<1000,]
    nom<-seq(round(min(Q$A)),floor(max(Q$A)),by=1)
    counts<-matrix(NA,nrow=length(nom),ncol=length(input$files1[,1]))
    return(list(as.matrix(nom),counts))
  })
  output$text1 <-renderPrint(if(is.null(input$files1)==FALSE) as.data.frame(mapz()[[1]]))
})}

shinyApp(ui, server)

Many thanks!

Answer 1

一种非常快速有效的方法是在上传文件或文件之前使UI的那部分不可用。基本上调用uiOutput()来代替actionButton()调用，并将actionButton()移动到服务器中的renderUI()函数中，该函数具有条件查找{{}的非NULL返回值1}}。除非mapz()有非NULL返回，否则按钮不可用。您还应该在mapz()之外移动创建mapz()的反应，以便无论是否按下该按钮，它都可以对应用程序使用。现在作为一个警告，这永远不会重置按钮，只要有上传的文件按钮是可按下的。它在功能上是一样的！运算符的工作方式类似于== FALSE条件。下面是建议更改的代码：

observeEvent()

Answer 2

不知道原因究竟是什么，但这似乎有效：

ui <- fluidPage(
  titlePanel("Uploading Files"),
  sidebarLayout(
    sidebarPanel(
      fileInput('files1', 'Choose CSV File',
                accept=c('text/csv', 
                         'text/comma-separated-values,text/plain', 
                         '.csv'), multiple = TRUE),
      tags$hr(),

      radioButtons('sep', 'Separator',
                   c(Comma=',',
                     Semicolon=';',
                     Tab='\t'),
                   ','),
      actionButton("go","run",class = "btn-primary"),br()
    ),
    mainPanel(tags$head(tags$style(type="text/css", "
                                   #loadmessage {
                                   position: fixed;
                                   top: 95%;
                                   left: 0px;
                                   width: 100%;
                                   padding: 5px 0px 5px 0px;
                                   text-align: center;
                                   font-weight: bold;
                                   font-size: 100%;
                                   color: #000000;
                                   background-color: #CCFF66;
                                   z-index: 105;
                                   }
                                   ")),
              conditionalPanel(condition="$('html').hasClass('shiny-busy')",
                               tags$div("Loading...",id="loadmessage")),
              verbatimTextOutput('text1')

    )
    )
    )


server <- function(input, output) {

  observeEvent(input$go,{
    mapz1 <- reactive({
      inFiles <- input$files1

      if (is.null(inFiles))
        return(NULL)
      Q <- read.csv(input$files1[[1, 'datapath']],sep=input$sep,dec="." )
      names(Q)<-c("A","B")
      Q<-Q[Q$A<1000,]
      nom<-seq(round(min(Q$A)),floor(max(Q$A)),by=1)
      counts<-matrix(NA,nrow=length(nom),ncol=length(input$files1[,1]))
      return(list(as.matrix(nom),counts))
    })
    mapz<-reactive({isolate(mapz1())})

    output$text1 <-renderPrint(as.data.frame(mapz()[[1]]))
  })}

shinyApp(ui, server)

stop calculation after upload of data until run is clicked again

2 个答案: