在RShiny中从下拉菜单中选择“绘图”

Question

我正在创建一个shiny应用程序，用户可以在其中选择要查看的plot。我使用this问题作为一种方法，但我得到了一个错误。我怎么才能解决这个问题？

用户界面

library(shiny)
library(shinydashboard)
library(shinythemes) 
library(tidyverse)

ui =   navbarPage("Project ", theme = shinytheme("cyborg")
                  uiOutput("all"),
       tabPanel("Plot",
                      icon = icon("chart-area"),
                      sidebarLayout(sidebarPanel(
                                    selectInput("Plot", "Please select a plot to view:",
                                                 choices = c("Plot-1", "Plot-2")),
                                    submitButton("Submit")),
                      plotOutput(outputId = "Plots",
                                   width = "1024px",
                               height = "768px")
              )))

服务器

server = function(input, output, session) {

data = eventReactive(input$Plot,{
            switch(input$Plot,
                   "Plot-1" = Plot1,
                   "Plot-1" = Plot2)
        })

output$Plots = renderPlot({

             data("midwest", package = "ggplot2") # Sample data

              Plot1 = ggplot(midwest, aes(x=area, y=poptotal)) +
                      geom_point()
              Plot2 =  ggplot(midwest, aes(x=area, y=poptotal)) + geom_point() + 
                       geom_smooth(method="lm")
 
        })
        

}

# Run the application 
shinyApp(ui = ui, server = server)

错误

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Answer 1

有个办法-

library(shiny)
library(shinydashboard)
library(shinythemes)

ui =   navbarPage("Project ", theme = shinytheme("cyborg"),
                  uiOutput("all"),
                  tabPanel("Plot",
                           icon = icon("chart-area"),
                           sidebarLayout(sidebarPanel(
                             selectInput("Plot", "Please select a plot to view:",
                                         choices = c("Plot-1", "Plot-2")),
                             actionButton("submit", "Submit")),
                             plotOutput(outputId = "Plots",
                                        width = "1024px",
                                        height = "768px")
                           )))

server = function(input, output, session) {
  
  observeEvent(input$submit,{

      Plot1 = ggplot(midwest, aes(x=area, y=poptotal)) +
        geom_point()
      Plot2 =  ggplot(midwest, aes(x=area, y=poptotal)) + geom_point() + 
        geom_smooth(method="lm")

  output$Plots = renderPlot({
    switch(isolate(input$Plot),
           "Plot-1" = Plot1,
           "Plot-2" = Plot2)
  })
  
  })
  

  
  
}

# Run the application 
shinyApp(ui = ui, server = server)