Classic Shiny app (blocking)

classicShiny.R

library(shiny)

ui <- fluidPage(
  
  # Application title
  titlePanel("Old Faithful Geyser Data"),
  
  # Sidebar with a slider input for number of bins 
  sidebarLayout(
    sidebarPanel(
      sliderInput("bins",
                  "Number of bins:",
                  min = 1,
                  max = 50,
                  value = 30),
      actionButton("MakePlot", "MakePlot")
    ),
    
    # Show a plot of the generated distribution
    mainPanel(
      fluidRow(
        column(6, plotOutput("distPlot")),
        column(6, plotOutput("FuturePlot")))
    )
  )
)

# Define server logic required to draw a histogram
server <- function(input, output) {
  
  output$distPlot <- renderPlot({
    # generate bins based on input$bins from ui.R
    x    <- faithful[, 2] 
    bins <- seq(min(x), max(x), length.out = input$bins + 1)
    
    # draw the histogram with the specified number of bins
    hist(x, breaks = bins, col = 'darkgray', border = 'white')
  })
  
  output$FuturePlot <- renderPlot({
    input$MakePlot
    Sys.sleep(5)
    plot(cbind(rnorm(1000), rnorm(1000)))
  })
  
}

shinyApp(ui = ui, server = server)