Portion of server.R that contains dynamic UI with renderUI and uiOutput for R Shiny Google Vision API project

shiny-vision-server-renderUI.R

### Body of image_analyze tab ###
output$image_analyze <- renderUI({
  ### Image upload UI Step ###
  if (values$analysis_stage == 1) {
    shiny::sidebarLayout(
      shiny::sidebarPanel(
        title = "Image and Analysis Selection",
        # ask for file input from user
        shiny::fileInput(
          inputId = "file1",
          label   = "Input Image",
          accept  = c(
            "image/png",
            "image/jpeg"
          )
        ),
        # provide dropdown menu to select analysis type
        shiny::selectInput(
          inputId = "analysis_type",
          label   = "Analysis Type",
          choices = c(  # key (seen from user): value (for code)
            "Select Analysis"     = "analysis_select",
            "Facial Detection"    = "FACE_DETECTION",
            "Label Detection"     = "LABEL_DETECTION",
            "Landmark Detection"  = "LANDMARK_DETECTION",
            "Logo Detection"      = "LOGO_DETECTION",
            "Object Localization" = "OBJECT_LOCALIZATION",
            "Text Detection"      = "TEXT_DETECTION"
          )
        ),
        # Allow for user to choose when to analyze with button
        shiny::actionButton("analyze", "Analyze!"),
        br(),
        # If file not uploaded or analysis type not selected, warning
        values$warning_inputs
      ),
      shiny::mainPanel(
        # do not need anything in here
      )
    )
    ### Image Analysis UI Step ###
  } else if (values$analysis_stage == 2) {
    # stage 2 within our renderUI function
    shiny::fluidPage(
      shiny::tagList(
      # Row 1: our analyzed image
      shiny::fluidRow(
        column(8, align = "center", 
          shinycssloaders::withSpinner(  # Spinner loading bar
            imageOutput("picture2"),  # Outputted Image
            color = '#999999'
          )
        )
      ),
      br(),
      br(),
      # Row 2: our table results
      shiny::fluidRow(
        column(8, align = "center",
          shinydashboard::box(
            width=12, 
            title = "Analysis Results",
            solidHeader = TRUE,
            DT::dataTableOutput("results"),  # Outputted table
            collapsible = TRUE,
            collapsed = FALSE,
            status = "primary"
          )
        )
      ),
      br(),
      br(),
      # Row three: our restart button
      shiny::fluidRow(
        column(8, align = "center",
          shiny::actionButton("reset", "Restart") 
        )
      )
    )
  )
}
})