我正在设计一个R Shiny应用程序，我已经能够将选定的文件名显示回单选按钮。
然而，我尝试了很多方法，包括从AI bot那里获得帮助，但都没有成功。我希望能够在点击带有文件名的单选按钮后再次可视化数据，而不必从头开始重新选择文件。下面是我的server.R代码：

library(shiny)
library(ggplot2)
library(dplyr)
library(readr)
library(lubridate)

selectedFileNames <- reactiveVal(character(0))

shinyServer(function(input, output, session) {
  data <- reactive({
    req(input$file)
    selectedFileName <- input$file$name

    if (!(selectedFileName %in% selectedFileNames())) {
      selectedFileNames(c(selectedFileNames(), selectedFileName))
    }
    
    read.csv(input$file$datapath, stringsAsFactors = FALSE)
  })
  
  observe({
    updateRadioButtons(session, "selectedOption", choices = c("", selectedFileNames()), selected = input$selectedOption)
  })
  
  
  filteredData <- reactive({
    data_filtered <- data()
    date_range <- input$dateRange
    if (!is.null(date_range)) {
      start_date <- as.POSIXct(date_range[1], format = "%Y-%m-%d", tz = "UTC")
      end_date <- as.POSIXct(date_range[2], format = "%Y-%m-%d", tz = "UTC")
      data_filtered <- data_filtered %>%
        filter(between(as.POSIXct(Start.Time), start_date, end_date))
    }
    data_filtered
  })
  
  output$userSearchPlot <- renderPlot({
    ggplot(filteredData(), aes(x = as.Date(Start.Time), fill = factor(User))) +
      geom_bar() +
      labs(title = "Number of User Searches Over Time",
           x = "Date",
           y = "Number of Searches",
           fill = "User") +
      theme_minimal() +
      scale_x_date(date_labels = "%Y-%m-%d", date_breaks = "1 day") +
      theme(axis.text.x = element_text(angle = 90, hjust = 1))
  })
  
  output$summaryText <- renderPrint({
    summary_data <- filteredData() %>%
      group_by(date = as.Date(Start.Time)) %>%
      summarise(NumUsers = n_distinct(User), NumSearches = n()) %>%
      as.data.frame()
    
    summary_label <- "Summary of User Searches Over Time"

    colnames(summary_data) <- c("Date", "Number of User", "Number of Searcher")

    cat(summary_label, "\n")
    print(summary_data)
  })
})

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