How to make Shiny wait until you hit submit

user_5656723 0
Viewed 5806

So I am building an R Shinny app that runs a simulation study and so every time the user changes one of the inputs I don't want the app to start running the simulations until they hit a submit button. How can I achieve this?

Here is the code I have so far:

The UI file:

#ui.R
# Define UI for random distribution application 
shinyUI(fluidPage(

  # Application title
  titlePanel("ORR Simulator"),

  # Sidebar with controls to select the random distribution type
  # and number of observations to generate. Note the use of the
  # br() element to introduce extra vertical spacing
  sidebarLayout(
    sidebarPanel(
          fileInput('file1', 'Select the XXX.csv file',
                accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
      tags$hr(),
          fileInput('file2', 'Select the YYY.csv file',
                accept=c('text/csv','text/comma-separated-values,text/plain','.csv')),
      tags$hr(),
     numericInput("S", "Number of simulations to run:", 100),

       mainPanel(
plotOutput("plot")
    )
  )
))

And so I would like for there to be a button that says something like submit and once they push that the actual R programs runs rather than running as soon as they change any input.

shiny r
2 Answers

I had the same problem as you. Shiny waited for the first submit and when I typed a text a second time it immedialtely began to calculate. The solution I found is easy. Instead of using observeEvent you need to use eventReactive. I found it here

library(shiny)

ui <- fluidPage(
  headerPanel("Example eventReactive"),
  
  mainPanel(
    
    # input field
    textInput("user_text", label = "Enter some text:", placeholder = "Please enter some text."),

    # submit button
    actionButton("submit", label = "Submit"),
    
    # display text output
    textOutput("text"))
)

server <- function(input, output) {
  
  # reactive expression
  text_reactive <- eventReactive( input$submit, {
    input$user_text
  })
  
  # text output
  output$text <- renderText({
    text_reactive()
  })
}

shinyApp(ui = ui, server = server)
user_127120300
Related