前言：

Shiny是一款R软件包，能够构建交互式Web应用，功能十分强大。官网地址：https://shiny.rstudio.com/

Shiny官网主页

install.packages("shiny")

2.运行示例
shiny中内置了很多使用示例，可以直接运行：

library(shiny)#导入shiny包
runExample("01_hello")#运行内置示例"01_hello"

弹出交互式窗口

3.Shiny apps的构成
Shiny apps包含一个R script即app.R,位于某个目录下如(newdir/),app可以通过函数runApp("newdir/app.R")运行。
app.R 包括三部分:
1.a user interface object
2.a server function
3.a call to the shinyApp function
即：1.用户界面（ui）object 控制应用程序的布局和外观。2.server function包含构建应用程序所需的说明。3.最后，shinyApp function通过ui和server创建Shiny应用程序对象。
4.自己构建交互程序
只要准备好app.R的三个部分，就是一个完整的交互式应用程序了，可以看下边的举例：
1）首先需要安装maps，mapproj包

install.packages(c("maps", "mapproj"))

2）数据下载
首先下载美国地图数据counties.rds，
然后下载帮助统计数据的脚本helpers.R
其次，将文件布置在文件夹中，命名为census-app，在其中创建data文件夹，将counties.rds文件放在里面，然后helpers.R放在census-app目录下，如图:

census-app

# Load packages ----
library(shiny)
library(maps)
library(mapproj)

# Load data ----
counties <- readRDS("data/counties.rds")

# Source helper functions -----
source("helpers.R")

# User interface ----
ui <- fluidPage(
  titlePanel("censusVis"),
  
  sidebarLayout(
    sidebarPanel(
      helpText("Create demographic maps with 
        information from the 2010 US Census."),
      
      selectInput("var", 
                  label = "Choose a variable to display",
                  choices = c("Percent White", "Percent Black",
                              "Percent Hispanic", "Percent Asian"),
                  selected = "Percent White"),
      
      sliderInput("range", 
                  label = "Range of interest:",
                  min = 0, max = 100, value = c(0, 100))
    ),
    
    mainPanel(plotOutput("map"))
  )
)

# Server logic ----
server <- function(input, output) {
  output$map <- renderPlot({
    data <- switch(input$var, 
                   "Percent White" = counties$white,
                   "Percent Black" = counties$black,
                   "Percent Hispanic" = counties$hispanic,
                   "Percent Asian" = counties$asian)
    
    color <- switch(input$var, 
                    "Percent White" = "darkgreen",
                    "Percent Black" = "black",
                    "Percent Hispanic" = "darkorange",
                    "Percent Asian" = "darkviolet")
    
    legend <- switch(input$var, 
                     "Percent White" = "% White",
                     "Percent Black" = "% Black",
                     "Percent Hispanic" = "% Hispanic",
                     "Percent Asian" = "% Asian")
    
    percent_map(data, color, legend, input$range[1], input$range[2])
  })
}

# Run app ----
shinyApp(ui, server)

保存app.R文件并运行runApp("census-app")

library(shiny)
runApp("census-app")

运行结果：

census-app运行结果