Shiny + ggplot2: reactive value plotted as factor

Question

I'm attempting to draw a heatmap visualizing different measures of engagement along several social media platforms. I have followed the suggested workarounds to handle several of the problems between shiny and ggplot2, but am stuck on this last one:

My ui.R file

    # ui.R

    library(shiny)

    # Define UI for application that draws a heat map
    shinyUI(fluidPage(

      # Application title
      titlePanel("Social Media"),

      # select platform and measure 
      sidebarLayout(
        sidebarPanel(
          selectInput("medium", "Choose a platform:",
            choices = c("twitter", "facebook", "linkedin")),
        selectInput("measure", "Choose a measure:",
          choices = c("audience", "reach", "kudos", "engagement", "clicks"))
        ),

        # plot heat of measure
        mainPanel(
          plotOutput('heat'))
      )
    ))

my server.R file

server.R

    library(shiny)
    library(ggplot2)
    library(dplyr)
    library(readr)

    social_media <- read_csv("data/social_media.csv")

    # Define server logic required to draw a heat map
    shinyServer(function(input, output) {

       output$heat <- renderPlot({

           plot_data <- reactive({
               social_media %>%
               filter(social_media$source==input$medium)
            }) 

            ggplot(plot_data(), aes_string(x="hour_of_day", y="day"),
                environment = environment()) +
                geom_raster(aes_string(fill="input$measure")) 

        })

    })

Rather than the heat map I expect, I get a monochromatic plot where the fill appears to be the metric plotted as a factor: http://i.imgur.com/tA6kX7d.png) http://i.imgur.com/8RLU453.png

The variable names in my dataset correspond to the select inputs: Source: local data frame [6 x 20]

           time       date
          (chr)     (time)
    1 03:55 PM  2014-01-02
    2 03:30 PM  2014-01-03
    3 04:30 PM  2014-01-06
    4 06:04 PM  2014-01-07
    5 11:53 AM  2014-01-08
    6 04:15 PM  2014-01-08
    Variables not shown: message text (chr), audience (int), reach (int), kudos (int), engagement (int), author (chr),
      account name (chr), message URL (chr), clicks (int), tags (chr), source (chr), datetime (chr), date_time (time),
      hour_of_day (int), day (fctr), week (dbl), month (fctr), year (dbl)

I don't know what else to do. Thoughts?

Rorschach Rorschach · Accepted Answer · 2016-03-13T23:57:47

change fill="input$measure" to fill=input$measure. That variable will be a string already. Your code is currently considering the fill data to be a single string (or factor cause its ggplot), "input$measure".

Shiny + ggplot2: reactive value plotted as factor

server.R

1 Answers