Shiny应用点击下载按钮后添加下载等待提示功能的实现咨询

实现方案 #

我们仅需对原有下载逻辑做少量修改即可实现需求：利用Shiny自带的通知组件，在文件生成前弹出持久化的下载提示，文件生成完成后自动关闭提示。修改后的完整可运行代码如下：

library(shiny)
library(shinythemes)
library(dplyr)
library(writexl)
library(tidyverse)
library(lubridate)

function.test<-function(){
  
  df1 <- structure(
    list(date1= c("2021-06-28","2021-06-28","2021-06-28"),
         date2 = c("2021-07-01","2021-07-02","2021-07-04"),
         Category = c("ABC","ABC","ABC"),
         Week= c("Wednesday","Wednesday","Wednesday"),
         DR1 = c(4,1,0),
         DR01 = c(4,1,0), DR02= c(4,2,0),DR03= c(9,5,0),
         DR04 = c(5,4,0),DR05 = c(5,4,0),DR06 = c(5,4,0),DR07 = c(5,4,0),DR08 = c(5,4,0)),
    class = "data.frame", row.names = c(NA, -3L))
  
  return(df1)
  
}

return_coef <- function(df1, dmda, CategoryChosse) {

x<-df1 %>% select(starts_with("DR0"))

x<-cbind(df1, setNames(df1$DR1 - x, paste0(names(x), "_PV")))
PV<-select(x, date2,Week, Category, DR1, ends_with("PV"))

med<-PV %>%
  group_by(Category,Week) %>%
  summarize(across(ends_with("PV"), median))

SPV<-df1%>%
  inner_join(med, by = c('Category', 'Week')) %>%
  mutate(across(matches("^DR0\\d+$"), ~.x + 
                  get(paste0(cur_column(), '_PV')),
                .names = '{col}_{col}_PV')) %>%
  select(date1:Category, DR01_DR01_PV:last_col())

SPV<-data.frame(SPV)

mat1 <- df1 %>%
  filter(date2 == dmda, Category == CategoryChosse) %>%
  select(starts_with("DR0")) %>%
  pivot_longer(cols = everything()) %>%
  arrange(desc(row_number())) %>%
  mutate(cs = cumsum(value)) %>%
  filter(cs == 0) %>%
  pull(name)

(dropnames <- paste0(mat1,"_",mat1, "_PV"))

SPV <- SPV %>%
  filter(date2 == dmda, Category == CategoryChosse) %>%
  select(-any_of(dropnames))

if(length(grep("DR0", names(SPV))) == 0) {
  SPV[head(mat1,10)] <- NA_real_
}

datas <-SPV %>%
  filter(date2 == ymd(dmda)) %>%
  group_by(Category) %>%
  summarize(across(starts_with("DR0"), sum)) %>%
  pivot_longer(cols= -Category, names_pattern = "DR0(.+)", values_to = "val") %>%
  mutate(name = readr::parse_number(name))
colnames(datas)[-1]<-c("Days","Numbers")


datas <- datas %>% 
  group_by(Category) %>% 
  slice((as.Date(dmda) - min(as.Date(df1$date1) [
    df1$Category == first(Category)])):max(Days)+1) %>%
  ungroup

m<-df1 %>%
  group_by(Category,Week) %>%
  summarize(across(starts_with("DR1"), mean))

m<-subset(m, Week == df1$Week[match(ymd(dmda), ymd(df1$date2))] & Category == CategoryChosse)$DR1


if (nrow(datas)<=2){
  return (as.numeric(m))
}

else if(any(table(datas$Numbers) >= 3) & length(unique(datas$Numbers)) == 1){
  yz <- unique(datas$Numbers)
  return(as.numeric(yz))

}

else{
  mod <- nls(Numbers ~ b1*Days^2+b2,start = list(b1 = 0,b2 = 0),data = datas, algorithm = "port")
   return(as.numeric(coef(mod)[2]))
}

}



ui <- fluidPage(
  
  shiny::navbarPage(theme = shinytheme("flatly"), collapsible = TRUE,
                    br(),
                    tabPanel("",
                             sidebarLayout(
                               sidebarPanel(
                                 uiOutput('daterange'),
                                 br()
                                 
                               ),
                               mainPanel(
                                 dataTableOutput('table'),
                                 br(), br(),
                                 downloadButton("dl", "Download")
                               ),
                             ))
  ))

server <- function(input, output,session) {
  
  data <- reactive(function.test())
  
  data_subset <- reactive({
    req(input$daterange1)
    req(input$daterange1[1] <= input$daterange1[2])
    days <- seq(input$daterange1[1], input$daterange1[2], by = 'day')
    df1 <- subset(data(), as.Date(date2) %in% days)
    df2 <- df1 %>% select(date2,Category)
    Test <- cbind(df2, coef = apply(df2, 1, function(x) {return_coef(df1,x[1],x[2])}))
    Test
  })
  
  output$daterange <- renderUI({
    dateRangeInput("daterange1", "Period you want to see:",
                  min = min(data()$date2),
                  max   = max(data()$date2))
  })
  
  output$table <- renderDataTable({
    data_subset()
  })
  
  output$dl <- downloadHandler(
    filename = function() { "data.xlsx"},
    content = function(file) {
      # 弹出下载中提示，设置duration为NULL则一直展示到手动关闭
      showNotification(
        ui = "请稍候，电子表格正在下载中",
        id = "download_notice",
        duration = NULL,
        type = "message"
      )
      writexl::write_xlsx(data_subset(), path = file)
      # 文件生成完成后关闭提示
      removeNotification(id = "download_notice")
    }
  )
}

shinyApp(ui = ui, server = server) 

可选参数调整说明

如果需要自定义提示效果，可以修改showNotification的参数：

• 修改duration参数为数字（单位为秒）即可设置固定展示时长，到期后提示自动消失
• 修改position参数可调整提示展示位置，可选值为bottom-right/top-right/bottom-left/top-left
• 修改type参数可切换提示样式，可选值为message/warning/error

内容的提问来源于stack exchange，提问作者Antonio