Insert warning message in Shiny

问题

I would like to insert a alert message when the file inserted in fileInput was different from ".xlsx", ".shp", ".shx", ".dbf". Can you help me? I entered an executable code below. You can even see it in my observeEvent (input$data, which I inserted something similar, but I would like it to be presented as a text box in Shiny.

Thank you!

library(shiny)
library(ggplot2)
library(shinythemes)
library(rdist)
library(openxlsx) 
library(geosphere)
library(rgdal)

function.cl<-function(df,k){
 
}

ui <- bootstrapPage(
  navbarPage(theme = shinytheme("flatly"), collapsible = TRUE,
             "Cl", 
             tabPanel("Solution",
                      fileInput("data", h3("Excel or Shapefile import"),
                                accept = c(".xlsx",".shp",".shx",".dbf"),
                                multiple= T),  
                      sidebarLayout(
                        sidebarPanel(
                          
                          sliderInput("Slider", h5(""),
                                      min = 2, max = 4, value = 3)
                        ),
                        mainPanel(
                          tabsetPanel(      
                            tabPanel("Solution", plotOutput("ScatterPlot"))))
                        
                      ))))

server <- function(input, output, session) {
  
  v <- reactiveValues(df = NULL)
  
  observeEvent(input$data, {
    if(any(grepl(".xlsx",input$data$name))){
      v$df <- read.xlsx(input$data$datapath) 
    }else if(any(grepl(".shp",input$data$name))){
      shpDF <- input$data
      failed <- F
      if(!any(grepl(".shx",input$data$name))){
        failed<-T
      }
      
      if(!any(grepl(".dbf",input$data$name))){
        failed<-T
      }
      
      if(failed){
        print("You Need 3 files, '*.shp', '*shx' and '*.dbf'")
      }else{
        prevWD <- getwd()
        uploadDirectory <- dirname(shpDF$datapath[1])
        setwd(uploadDirectory)
        for (i in 1:nrow(shpDF)){
          file.rename(shpDF$datapath[i], shpDF$name[i])
        }
        shpName <- shpDF$name[grep(x=shpDF$name, pattern="*.shp")]
        shpName<-substr(shpName,1,nchar(shpName)-4)
        
        setwd(prevWD)
        shpFile<-readOGR(dsn=uploadDirectory,layer=shpName)
        
        v$df<-shpFile@data
      } 
    }else{
      print("Wrong File")
    }
  })
  
  
  Modelcl<-reactive({if (!is.null(v$df)) {
    function.cl(v$df,input$Slider)
  }
  })
  
  
  output$ScatterPlot <- renderPlot({
    Modelcl()[[1]]
  })
  
}

shinyApp(ui = ui, server = server)

回答1:

As @Stéphane Laurent already pointed out in the comments, shinyWidgets can be used to display sweet alerts. For some inputs the {shinyFeedback} package will work as well, however, fileInputs are not supported yet.

Below is one possible implementation using sendSweetAlert replacing your print calls.

library(shiny)
library(shinyWidgets)
library(ggplot2)
library(shinythemes)
library(rdist)
library(openxlsx) 
library(geosphere)
library(rgdal)

function.cl<-function(df,k){
  
}

ui <- bootstrapPage(
  navbarPage(theme = shinytheme("flatly"), collapsible = TRUE,
             "Cl", 
             tabPanel("Solution",
                      fileInput("data", h3("Excel or Shapefile import"),
                                accept = c(".xlsx",".shp",".shx",".dbf"),
                                multiple= T),  
                      sidebarLayout(
                        sidebarPanel(
                          
                          sliderInput("Slider", h5(""),
                                      min = 2, max = 4, value = 3)
                        ),
                        mainPanel(
                          tabsetPanel(      
                            tabPanel("Solution", plotOutput("ScatterPlot"))))
                        
                      ))))

server <- function(input, output, session) {
  
  v <- reactiveValues(df = NULL)
  
  observeEvent(input$data, {
    if(any(grepl(".xlsx",input$data$name))){
      v$df <- read.xlsx(input$data$datapath) 
    }else if(any(grepl(".shp",input$data$name))){
      shpDF <- input$data
      failed <- F
      if(!any(grepl(".shx",input$data$name))){
        failed<-T
      }
      
      if(!any(grepl(".dbf",input$data$name))){
        failed<-T
      }
      
      if(failed){
        
        sendSweetAlert(
          session = session,
          title = "Error !!",
          text = "You Need 3 files, '*.shp', '*shx' and '*.dbf'",
          type = "error"
        )
        
      }else{
        prevWD <- getwd()
        uploadDirectory <- dirname(shpDF$datapath[1])
        setwd(uploadDirectory)
        for (i in 1:nrow(shpDF)){
          file.rename(shpDF$datapath[i], shpDF$name[i])
        }
        shpName <- shpDF$name[grep(x=shpDF$name, pattern="*.shp")]
        shpName<-substr(shpName,1,nchar(shpName)-4)
        
        setwd(prevWD)
        shpFile<-readOGR(dsn=uploadDirectory,layer=shpName)
        
        v$df<-shpFile@data
      } 
    }else{
      sendSweetAlert(
        session = session,
        title = "Error !!",
        text = "Wrong File",
        type = "error"
      )
    
      }
  })
  

  Modelcl<-reactive({if (!is.null(v$df)) {
    function.cl(v$df,input$Slider)
  }
  })
  
  
  output$ScatterPlot <- renderPlot({
    Modelcl()[[1]]
  })
  
}

shinyApp(ui = ui, server = server)

来源：https://stackoverflow.com/questions/62613323/insert-warning-message-in-shiny