R Shiny DT 自动在新添加的行中生成一个值

Question

我有一个Shiny的应用程序，允许用户将他们的project details输入数据库。 这是通过向表中添加空行的“ Add Project Details Button来实现的。 现在下一步是：

• 单击添加按钮时，应用程序会根据前一个参考号在新行中自动生成下一个reference number （在Reference.Number列下）。 因此，就像基于下面的sample data一样，因为最后一个reference number是33335 ，下一个参考编号将是33336 。 如果添加另一行，那么它将是33337 。

我怎样才能做到这一点？

样本数据（ df ）：

df <- structure(list(Reference.Number = c("33331", "33332", "33333", 
                                          "33334", "33335"), 
                     Request.Date = c("1/6/2022", "1/6/2022", "1/19/2022", 
                                                                              "1/20/2021", "1/24/2022"), 
                     Requestor.Name = c("Comm Dist 3 by Kitty", "Comm Dist 3 by Kitty", "Updated maps for David", "    Stone Cold", "Updated SOE 60 inch wall map"),
                     Requestor.Dept.Div = c("C 3 Staff",    "C 3 Staff", "Unincorp & Comm", "Mt.Rushmore AME Church Ft. Billy",                                         "SOE"), 
                     Requestor.Phone = c("", "", "", "", ""), 
                     Contact.Person = c("Tommy",                             "Tommy", "Bob", "Bob", "Joe"),
                     Contact.Phone = c("1111",                               "2222", "3333", "ext 1111", "3434"),
                     Deadline = c("1/20/2022",         "1/20/2022", "1/22/2022", "", "1/24/2022"),
                     Project.Description = c("45x36 portrait map ",          "45x36 portrait map  ",   "24x24 Unincorporated areas", "Percent Females Aged 25 - 55  Below Poverty Level By Zip Code",                "SOE Wall Map 60x60 p"), 
                     Project.File.Location = c("", 
                                                  "", "C:\\ABC\\Tommy\\work|Map-Projects\\BD Unincororated\\#14785 Unincorporated 24x24.pdf", 
                                                  "C:\\ABC\\Demographics\\Demographic_Request\\FemalesAge10-18BelowPoveryLevel\\FemalesAge10-18BelowPoveryLevel.aprx", 
                                                  "C:\\ABC\\Tommy\\work|Map-Projects\\BD Unincororated\\#14786 V P 60x60.pdf"
                                                                                                                                                                                                                                                                                                                                                                             ), PDF.File.....Map.Name.... = c("", "", "", "C:\\ABC\\Demographics\\Demographic_Request\\FemalesAge10-18BelowPoveryLevel\\pdfs\\MapNo14785.pdf", 
                                                                                                                                                                                                                                                                                                                                                                                                              ""), Assigned.To = c("", "", "", "", ""), Completion.Date = c("", 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                            "", "", "", ""), Notes = c(NA, NA, NA, NA, NA), Year = c(2022, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     2022, 2022, 2022, 2022)), class = "data.frame", row.names = c(NA, -5L)) 

代码：

library(shiny)
library(shinythemes)
library(shinyWidgets)
library(shinyanimate)
library(DT)
library(tidyverse)

# Define UI for application that draws a histogram
ui =   navbarPage(tags$style("table, .table {color: unset;} .dataTable th, .datatables input {color: white}"),
                  title = div("GIS Team Projects"),
                  theme = shinytheme("cyborg"),
                  tabPanel("GIS Projects",
                           icon = icon("info"),
                           div(p(h1("Instructions:"),style="text-align: justify;")),
                           p("1. The user can add their project details.", style="color:black"),
                           uiOutput("all"),
                  sidebarLayout(
                    sidebarPanel(
                      actionButton("addData", "Add Project Details"),
                      ),
                    mainPanel(
                      downloadButton("download1","Download data as csv"),                
                      DTOutput("contents")),)
                    )
)

# Define server logic required to draw a histogram
server <- function(input, output) {

  myData = df
  
  # Create an 'empty' tibble 
   user_table =
     myData %>% 
      slice(1) %>% 
    # Transpose the first row of test into two columns
    gather(key = "column_name", value = "value") %>%
    # Replace all values with ""
    mutate(value = "") %>%
    # Reshape the data from long to wide
    spread(column_name, value) %>%
    # Rearrange the column order to match that of test
    select(colnames(myData))
   
   # Display data as is
   output$contents =
     renderDT(myData,
              server = FALSE,
              editable = TRUE,
              options = list(lengthChange = TRUE),
              rownames = FALSE)
   
   # Store a proxy of contents 
   proxy = dataTableProxy(outputId = "contents")
   
   # Each time addData is pressed, add user_table to proxy
   observeEvent(eventExpr = input$addData, {
     proxy %>% 
       addRow(user_table)
   })
  
}

# Run the application 
shinyApp(ui = ui, server = server)
   

Answer 1

myData应该是一个reactiveVal ：

library(shiny)
library(shinythemes)
library(shinyWidgets)
library(shinyanimate)
library(DT)
library(tidyverse)

# Define UI for application that draws a histogram
ui =   navbarPage(tags$style("table, .table {color: unset;} .dataTable th, .datatables input {color: white}"),
                  title = div("GIS Team Projects"),
                  theme = shinytheme("cyborg"),
                  tabPanel("GIS Projects",
                           icon = icon("info"),
                           div(p(h1("Instructions:"),style="text-align: justify;")),
                           p("1. The user can add their project details.", style="color:black"),
                           uiOutput("all"),
                           sidebarLayout(
                             sidebarPanel(
                               actionButton("addData", "Add Project Details"),
                             ),
                             mainPanel(
                               downloadButton("download1","Download data as csv"),                
                               DTOutput("contents")),)
                  )
)

# Define server logic required to draw a histogram
server <- function(input, output) {
  
  myData = reactiveVal(df)
  
  # Create an 'empty' tibble 
  user_table =  
    df %>% 
    slice(1) 
  
  user_table[1,]<-NA
  
  # Display data as is
  output$contents =
    renderDT(myData(),
             server = FALSE,
             editable = TRUE,
             options = list(lengthChange = TRUE),
             rownames = FALSE)
  
  # Store a proxy of contents 
  proxy = dataTableProxy(outputId = "contents")
  
  # Each time addData is pressed, add user_table to proxy
  observeEvent(eventExpr = input$addData, {
    myData(myData() %>% bind_rows(user_table %>% mutate(Reference.Number=as.character(max(as.numeric(myData()$Reference.Number))+1))))
  })
  
}

# Run the application 
shinyApp(ui = ui, server = server)