当用户在闪亮的应用程序中上传扩展名错误的文件时弹出显示

Question

在下面的应用程序中，当用户未上传 .xls 文件时，我希望显示一个弹出窗口。现在它只出现在开头，但如果上传另一个让我们说 doc 文件它是隐藏的。我不在乎它是用 shinyalert 包还是其他方法。

library(shiny)
library(shinyalert)

ui <- fluidPage(
  useShinyalert(),  # Set up shinyalert
  fileInput('file1', 'Choose xls file',
            accept = c(".xls")
  )
)

server <- function(input, output, session) {
  observeEvent(input$file1, {
    if (is.null(input$file1))
    # Show a modal when the button is pressed
    shinyalert("Oops!", "Something went wrong.", type = "error")
  }, ignoreNULL = FALSE)
}

shinyApp(ui, server)

Answer 1

这也会重置 fileInput:

library(shiny)
library(tools)

ui <- fluidPage(
  uiOutput("fileUpload")
)

server <- function(input, output, session) {
  
  showModal(modalDialog("My startup modal..."))
  
  resetFileUpload <- reactiveVal(FALSE)
  output$fileUpload <- renderUI({
    resetFileUpload() # reactive dependency
    resetFileUpload(FALSE)
    fileInput('file1', 'Choose xls file', accept = c(".xls"))
  })
  
  observeEvent(input$file1, {
    if(file_ext(input$file1$name) != "xls"){
      resetFileUpload(TRUE)
      showModal(modalDialog("That's not a .xls file"))
    }
  })
}

shinyApp(ui, server)

当用户在闪亮的应用程序中上传扩展名错误的文件时弹出显示

Display pop up when user uploads file with the wrong extension in shiny app

r

shiny