Question

我希望能够通过文件输入上传多张图像并显示在用户界面中选择的单张图像

ui.R

library(shiny)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      fileInput("file","Upload the file", multiple = TRUE), # fileinput() function is used to get the file upload contorl option
      uiOutput("selectfile")
    ),
    mainPanel(
      uiOutput('images')


    )

  )
)

server.R

server <- function(input,output) {


  ## Side bar select input widget coming through renderUI()
  # Following code displays the select input widget with the list of file loaded by the user
  output$selectfile <- renderUI({
    if(is.null(input$file)) {return()}
    list(hr(), 
         helpText("Select the files for which you need to see data and summary stats"),
         selectInput("Select", "Select", choices=input$file$name)
    )

  })

  output$images <- renderImage({
    if(is.null(input$file)) {return(NULL)}
    for (i in 1:nrow(input$file))
    {
      if(input$file$name[i] == input$Select){
        list(src=input$file$datapath[i],
             alt= "error")
        print(input$file$name[i])
        print(input$file$datapath[i])
      }
    }
  })
}

使用此解决方案，数据路径和名称的打印为我显示了正确的答案，但在尝试渲染图像后我仍然遇到相同的错误：“警告：基名错误：预期为字符向量参数”。 >

Answer 1

这是使用base64编码的解决方案。

library(shiny)
library(base64enc)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      fileInput("file", "Upload the file", multiple = TRUE), 
      uiOutput("selectfile")
    ),
    mainPanel(
      uiOutput('image')
    )
  )
)

server <- function(input,output) {
  output$selectfile <- renderUI({
    req(input$file)
    list(hr(), 
         helpText("Select the files for which you need to see data and summary stats"),
         selectInput("Select", "Select", choices=input$file$name)
    )
  })

  output$image <- renderUI({
    req(input$Select)
    i <- which(input$file$name == input$Select)
    if(length(i)){
      base64 <- dataURI(file = input$file$datapath[i], mime = input$file$type[i])
      tags$img(src = base64, alt= "error")
    }
  })
}

shinyApp(ui, server)

显示在Shiny UI中上传的选定图像

1 个答案: