conditionalShowPDF - R and Shiny code to conditionally display a PDF file from a list of PDFs given in a selectInput.

App.R

#########################################################################
# Conditionaly displays a PDF file from a list of PDFs given
# in a selectInput.
#
# Author: Pedro Carneiro Junior
# This version: September-10-2017, Goiania-GO-Brazil
#
# * Will not work in browsers that don't support iframe;
# * PDF files pdf_file_1.pdf to pdf_file_n.pdf must be placed under the "www" subdirectory;
# * For better performance, use "Open in browser" button.
#
# * Ref. #1: https://gist.github.com/aagarw30/d5aa49864674aaf74951
# * Ref. #2: https://gist.github.com/wch/9609200
#
#########################################################################

library(shiny)

# Define UI ----
ui <- fluidPage(
        titlePanel("Show PDF file in app depending on chosen option from selectInput"),
        sidebarLayout(
                sidebarPanel(
                        selectInput(inputId = "choice_selected",
                                    label = "Select the PDF of your choice",
                                    choices = c(
                                            "PDF 1"
                                            , "PDF 2"
                                            , "PDF 3"
                                            , "PDF N"
                                    ),
                                    selected = "PDF 1"
                        )
                ),
                mainPanel(
                        tabsetPanel(
                                tabPanel("PDF", uiOutput("ui")),
                                tabPanel("More details", tags$p("Selected choice:"), verbatimTextOutput("choice_selected_text"))
                        )
                )
        )
)

# Define server logic ----
server <- function(input, output) {
        
        output$ui <- renderUI({
                if (is.null(input$choice_selected))
                        return()
                
                # Depending on input$choice_selected, we'll generate a different
                # UI with the PDF and send it to the client.
                switch(input$choice_selected,
                       "PDF 1" = tags$iframe(style="height:580px; width:100%; scrolling=yes", src="pdf_file_1.pdf")
                       , "PDF 2" = tags$iframe(style="height:580px; width:100%; scrolling=yes", src="pdf_file_2.pdf")
                       , "PDF 3" = tags$iframe(style="height:580px; width:100%; scrolling=yes", src="pdf_file_3.pdf")
                       , "PDF N" = tags$iframe(style="height:580px; width:100%; scrolling=yes", src="pdf_file_n.pdf")
                )
        })
        
        output$choice_selected_text <- renderText({
                input$choice_selected
        })
        
}

# Run the app ----
shinyApp(ui = ui, server = server)