R Shiny ggplot2没有显示

Question

ui.R和server.R文件运行没有错误，但ggplot2没有显示。运行server.R文件只会在浏览器中创建一个名为in_range函数（x，range）的新函数。有谁知道如何解决这一问题？感谢。

server.R文件出现两个错误：

ui.R

require(shiny)

shinyUI(pageWithSidebar(

 headerPanel("Home Automation Data Model - TV"),

 sidebarPanel(

     wellPanel(
         selectInput(inputId = "x_var",
                     label = "X variable",
                     choices = c("Temperature (Celcius)" = "Temp", "Humidity (Percentage)" = "Hum", "Hours" = "Hrs"),
                     selected = "Temperature"
                     ),

         uiOutput("x_range_slider")
     ),


     wellPanel(
         selectInput(inputId = "y_var",
                     label = "Y variable",
                     choices = c("Breakdowns (Yes/No)" = "y"),
                     ),

         uiOutput("y_range_slider")
     ),


     wellPanel(
         p(strong("Model predictions")),
         checkboxInput(inputId = "mod_logistic",    label = "Logistic (dot-dash)"),
         conditionalPanel(
             condition = "input.mod_loess == true",
             sliderInput(inputId = "mod_loess_span", label = "Smoothing (alpha)",
                 min = 0.15, max = 1, step = 0.05, value = 0.75)
         )
     )
 ),

 mainPanel(
     plotOutput(outputId = "main_plot"),

     conditionalPanel("input.mod_logistic == true",
         p(strong("Logit model")),
         verbatimTextOutput(outputId = "mod_logistic_text")
     )
 )     

））

Server.R

library(ggplot2)

hw <- read.csv("LogitTV.csv")

in_range <- function(x, range) {
  x >= min(range) & x <= max(range)

}

shinyServer(function(input, output) {

  limit_data_range <- reactive {

  if (is.null(input$x_range) || is.null(input$y_range)) {
   return(NULL)
  }

  hw_sub <- hw[in_range(hw[[input$x_var]], input$x_range) &
               in_range(hw[[input$y_var]], input$y_range), ]

  hw_sub
}

output$main_plot <- renderPlot({


  hw_sub <- limit_data_range()

  if (is.null(hw_sub))
    return()


  xdat <- hw[[input$x_var]]
  ydat <- hw[[input$y_var]]


  if (input$mod_logistic)
    point_alpha <- 0.5  
  else
    point_alpha <- 1


  p <- ggplot(hw_sub, mapping = aes_mapping) +
    points +
    theme_bw() +
    scale_colour_hue(l = 40) +
    scale_shape(solid = FALSE) +

    scale_x_continuous(limits = range(xdat)) +
    scale_y_continuous(limits = range(ydat))


  if (max(input$x_range) != max(xdat)) {
    p <- p + geom_vline(xintercept = max(input$x_range), linetype = "dashed",
                      alpha = 0.3)
  }

  if (min(input$x_range) != min(xdat)) {
    p <- p + geom_vline(xintercept = min(input$x_range), linetype = "dashed",
                      alpha = 0.3)
  }

  if (max(input$y_range) != max(ydat)) {
    p <- p + geom_hline(yintercept = max(input$y_range), linetype = "dashed",
                      alpha = 0.3)
  }

  if (min(input$y_range) != min(ydat)) {
    p <- p + geom_hline(yintercept = min(input$y_range), linetype = "dashed",
                      alpha = 0.3)
  }


  if (input$mod_logistic) {
    p <- p + geom_smooth(method = lm, se = FALSE, size = 0.75,    
                       linetype = "dotdash")
  }

  print(p)
 })

output$x_range_slider <- renderUI({
 xmin <- floor(min(hw[[input$x_var]]))
 xmax <- ceiling(max(hw[[input$x_var]]))

 sliderInput(inputId = "x_range",
            label = paste("Limit range"),
            min = xmin, max = xmax, value = c(xmin, xmax))
})

output$y_range_slider <- renderUI({
 ymin <- floor(min(hw[[input$y_var]]))
 ymax <- ceiling(max(hw[[input$y_var]]))

 sliderInput(inputId = "y_range",
            label = paste("Limit range"),
            min = ymin, max = ymax, value = c(ymin, ymax))
})


make_model <- function(model_type, formula, ...) {

  hw_sub <- limit_data_range()
  if (is.null(hw_sub))
    return()


  do.call(model_type, args = list(formula = formula, data = quote(hw_sub), ...))
}

output$mod_logistic_text <- renderPrint({
  formula <- paste(input$y_var, "~", input$x_var)

})
Error in output$mod_logistic_text <- renderPrint({ : 
object 'output' not found
>   runApp("~/LogitTV.csv", port=8100)
Error in setwd(appDir) : cannot change working directory