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I'm using the dismo::maxent function to create plots, but the problem is they can take a really long time (a few minutes). I want to have two tabs, one with a plot of the map and likelihoods and another one showing variable importance. This is working, but I want a wait message/plot/screen on both tabs while model is running. It's 2 function calls, there is no loop, so a placeholder message is all I need. It would need to be displayed after the submit button is pressed each time but not there initially.

Here's the server.R

data <- read.csv("CFR_Vaccine_Map_Corrected.csv")
load("./bioclim_10m.Rdata")

shinyServer(
  function(input, output) {
    observe({
      if (!(is.null(input$checkGroup))) {
        print(input$years)
        print(input$checkGroup)
        year.range <- input$years[1]:input$years[2]
        filtered.cases <- which(data$Outbreak %in% input$checkGroup & 
                                  data$Year %in% year.range)
        maxent.model <- maxent(bioStack, data[filtered.cases,5:4])
        print("model comp")
        maxent.map <- predict(maxent.model, bioStack)
        print("plotting map")
        output$map <- renderPlot({
          plot(maxent.map, xlab="Longitude", ylab="Latitude")
        })
        output$significance <- renderPlot({
          plot(maxent.model)
        })
    }
  })
  }
)

and here's the ui.R

shinyUI(fluidPage(
  titlePanel("Vaccine-Preventable Outbreaks"),

  sidebarLayout(
    sidebarPanel(
      helpText("Create maximum entropy maps with information from 
               Council on Foreign Relations data on vaccine-preventable 
               outbreaks."),

      checkboxGroupInput("checkGroup", h3("Category"),
                         choices = list("Polio" = "Polio", 
                             "Whooping Cough" = "Whooping Cough", 
                             "Measles" = "Measles",
                             "Mumps" = "Mumps",
                             "Rubella" = "Rubella",
                             "Polio" = "Polio",
                             "Violence" = "Violence")),
      sliderInput("years", "Years of interest:",
              min = 2007, max = 2016, value = c(2007, 2016), sep=""),
      submitButton("Submit")
    ),
    mainPanel(
      tabsetPanel(
        tabPanel("Map", plotOutput("map")), 
        tabPanel("Variable Significance", plotOutput("significance")) 
      )
    )
  )
))
TomNash
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1 Answers1

1

Two possible solutions:

  1. Use the withProgress function within Shiny:

    observeEvent(input$button, { 
    withProgress(message = "calculation in progress", detail = "This may take a while", value = 0, { 
        incProgress(1) 
        # You code that takes a long time.
    }) 
})

  2. Use Javascript as identified in this answer

    R shiny: display "loading..." message while function is running

Community
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Xiongbing Jin
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