title: R: rCharts and Shiny: Rickshaw plot won't show
body: <p>After having a lot of fun getting the basic of shiny down using ggplot2, I'm trying out rCharts. However, I can't get the Rickshaw graph to display. Any help much appreciated; take it easy - I'm just getting use to this ;)</p>
  
  <pre><code>### ui
  
  library(shiny)
  require(devtools)
  install_github('rCharts', 'ramnathv')
  # moved from lower down so call to `showOutput` would not fail
  library(rCharts) 
  library(rattle)
  
  shinyUI(
  
    pageWithSidebar(
  
    headerPanel("Rickshaw test"),
  
      sidebarPanel(
  
        selectInput("variable", 
                    "Choice is arbitrary:",
                    c("Choice 1", "Choice 2")
                    )
        ),  
  
    mainPanel(
  
      showOutput("plot", "Rickshaw")
      )
    )
  )
  
  ### server
  
  
  data(weather)
  w = weather
  
  dateToSeconds = function (date) {
  
    date = as.POSIXct(as.Date(date), origin = "1970-01-01")
    as.numeric(date)
  }
  
  w$Date = dateToSeconds(w$Date)
  
  shinyServer(function(input, output) {
  
    output$mpgPlot = renderChart({
  
      rs = Rickshaw$new()    
      rs$layer(MinTemp ~ Date,
               data = w,
               type = "line")    
      return(rs)    
    })  
  })
  </code></pre>