R Shiny中的Ggplot2图形根据用户输入带有线

我想在我的Shiny App中制作一个图形，ggplot2用于按主题绘制有关用户选择的线。在这个问题中，我被告知如何在给定主题没有任何项目的情况下添加那些0（使用ankrun的答案）。现在，我正在寻找在闪亮的应用程序中拟合该图的想法，并考虑添加一个slideInput，您可以在其中选择该行的主题。这是我尝试过的：

# # # global # # #
#1. App
if("shiny" %in% rownames(installed.packages()) == FALSE){ install.packages("shiny") }
library(shiny)
#2. Easier data handling
if("dplyr" %in% rownames(installed.packages()) == FALSE){ install.packages("dplyr") }
library(dplyr)
#3. Graphs
if("ggplot2" %in% rownames(installed.packages()) == FALSE){ install.packages("ggplot2") }
library(ggplot2)
#4. Completion in graphs
if("tidyr" %in% rownames(installed.packages()) == FALSE){ install.packages("tidyr") }
library(tidyr)

# # # ui # # #
ui <- fluidPage( 
  sidebarPanel(
    selectInput("select_topic_timeline", "What topic?",
                choices = c("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12"), 
                selected =  c("1", "2", "3", "4","5", "6", "7", "8", "9", "10", "11", "12"),
                multiple = T)
  ),#sidebarPanel
  mainPanel( 
    plotOutput("per_topic_timeline")
  ) #mainPanel
) #fluidPage

# # # server # # #
server <- function(input, output, session) {

  # TIMELINE PER TOPIC PER YEAR
  output$per_topic_timeline <- renderPlot({
  dtd2 <- structure(list(Topic = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
                                             1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
                                             3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 
                                             5L, 5L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 
                                             7L, 7L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 9L, 9L, 9L, 9L, 9L, 9L, 
                                             10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 11L, 11L, 11L, 11L, 
                                             11L, 11L, 11L, 11L, 11L, 12L, 12L, 12L, 12L, 12L, 12L, 12L), .Label = c("Topic 1", 
                                                                                                                     "Topic 10", "Topic 11", "Topic 12", "Topic 2", "Topic 3", "Topic 4", 
                                                                                                                     "Topic 5", "Topic 6", "Topic 7", "Topic 8", "Topic 9"), class = "factor"), 
                         Year = structure(c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 2L, 
                                            3L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 
                                            3L, 4L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 
                                            9L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 
                                            8L, 9L, 1L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 6L, 7L, 8L, 
                                            9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 
                                            6L, 7L, 8L, 9L, 2L, 3L, 4L, 5L, 6L, 7L, 8L), .Label = c("2011", 
                                                                                                    "2012", "2013", "2014", "2015", "2016", "2017", "2018", "2019"
                                            ), class = "factor"), Count = c(3L, 3L, 3L, 5L, 5L, 11L, 
                                                                            17L, 14L, 4L, 1L, 1L, 4L, 2L, 3L, 9L, 4L, 2L, 1L, 3L, 4L, 
                                                                            5L, 18L, 23L, 19L, 15L, 1L, 5L, 6L, 8L, 11L, 17L, 7L, 1L, 
                                                                            3L, 6L, 4L, 20L, 21L, 18L, 12L, 3L, 1L, 1L, 2L, 5L, 5L, 11L, 
                                                                            5L, 2L, 1L, 1L, 2L, 2L, 5L, 7L, 23L, 9L, 1L, 1L, 2L, 3L, 
                                                                            6L, 4L, 9L, 8L, 1L, 1L, 6L, 2L, 3L, 3L, 1L, 3L, 2L, 5L, 7L, 
                                                                            11L, 11L, 28L, 11L, 2L, 1L, 2L, 2L, 5L, 6L, 5L, 16L, 3L, 
                                                                            4L, 2L, 2L, 7L, 6L, 8L, 6L)), row.names = c(NA, -96L), class = "data.frame")

  dtd2 %>%
      expand(Topic = factor(Topic, levels = gtools::mixedsort(levels(c(input$select_topic_timeline)))) ,
             Year = unique(Year)) %>% 
      left_join(dtd2) %>% 
      mutate(Count = replace_na(Count, 0)) %>%
      ggplot(aes(x = Year, y = Count), colour = c(input$select_topic_timeline), group = Topic) + 
      geom_point() +
      geom_line() +
      labs(x = "Year", y = NULL, title = "Timeline")
  })
}

shinyApp(ui,server)

它并没有打印出任何错误，而是说Warning: Column "Topic" joining factors with different levels, coercing to character vector并且没有给出任何图形，只有一个空的灰色框。我不确定如何在图形代码中适合输入内容，我必须将其更改为错误！