More widgets这个应用程序展示的是帮助文本和提交按钮，以及用嵌入HTML元素的方式来自定义格式。要运行例子，请键入：

> library(shiny) > runExample("07_widgets") 

UI增强

在这个例子里，我们更新了Shiny Text程序，增加了控件，调整了格式，特别地：

• 增加了helpText控件，用以在输入控件旁边添加解释文本。
• 增加了 submitButton控件，用来表示我们不想让输入和输出进行实时连接，而是想让用户点击按钮后才更新输出。这一特点在当计算过程非常复杂时是很有用的。
• 在输出面板上增加了 h4 元素（四级标题）。Shiny提供了大量的函数可直接往页面上添加HTML元素，包括标题、段落、链接等等。

下面更新后的用户接口界面的代码：

library(shiny) # Define UI for dataset viewer application shinyUI(pageWithSidebar( # Application title. headerPanel("More Widgets"), # Sidebar with controls to select a dataset and specify the number # of observations to view. The helpText function is also used to  # include clarifying text. Most notably, the inclusion of a  # submitButton defers the rendering of output until the user  # explicitly clicks the button (rather than doing it immediately # when inputs change). This is useful if the computations required # to render output are inordinately time-consuming. sidebarPanel( selectInput("dataset", "Choose a dataset:", choices = c("rock", "pressure", "cars")), numericInput("obs", "Number of observations to view:", 10), helpText("Note: while the data view will show only the specified", "number of observations, the summary will still be based", "on the full dataset."), submitButton("Update View") ), # Show a summary of the dataset and an HTML table with the requested # number of observations. Note the use of the h4 function to provide # an additional header above each output section. mainPanel( h4("Summary"), verbatimTextOutput("summary"), h4("Observations"), tableOutput("view") ) )) 

服务端脚本

和原来的Shiny Text的程序比，所有的变化都是在用户接口界面部分，服务端脚本保持不变。

library(shiny) library(datasets) # Define server logic required to summarize and view the selected dataset shinyServer(function(input, output) { # Return the requested dataset datasetInput <- reactive({ switch(input$dataset, "rock" = rock, "pressure" = pressure, "cars" = cars) }) # Generate a summary of the dataset output$summary <- renderPrint({ dataset <- datasetInput() summary(dataset) }) # Show the first "n" observations output$view <- renderTable({ head(datasetInput(), n = input$obs) }) })