Generate table and clickable images in Shiny R

Question

I need to do the following in R:

1) Dynamically(for X images in ...) create a table/grid where I display them, for example in a 4xN table.

2) Make each of those images clickable, so that it feeds its name into a function in R. For example if we clicked on a monkey, it is supposed to call a function: selected(monkey.jpg).

Answer 1

Feels like cheating but using a little JS is the easiest way.

In your ui.R, put this somewhere (like inside your mainPanel or whatever):

uiOutput("imageGrid"),
tags$script(HTML(
  "$(document).on('click', '.clickimg', function() {",
  "  Shiny.onInputChange('clickimg', $(this).data('value'));",
  "};"
))

In your server function:

output$imageGrid <- renderUI({
  fluidRow(
    lapply(images, function(img) {
      column(3, 
        tags$img(src=paste0("images/", img), class="clickimg", data-value=img)
      )
    })
  )
})

Then in your server function you can access input$clickimg to determine the last clicked images. Keep in mind this'll be a reactive value (just like any other input), so you have to access it from within a reactive expression or output rendering function (or observer if you're a more advanced Shiny user). Oh and the initial value will be NULL so don't forget to check for that too.