我对Shiny Apps相当新，我希望将这些图作为png / pdf文件下载。在线发布应用程序后，下载的文件名是正确的，但它是一个空文件。我在downloadHandler的内容中应用了print函数，但它似乎没有用。谁能帮我吗？感谢
ui.r
library(shiny)
ui <- fluidPage(
titlePanel("My First Shiny Project"),
sidebarLayout(
sidebarPanel(
selectInput("select","Choose a Dataset",
choices = list("trees","pressure"),
selected = "pressure"),
selectInput("format","Choose file format",
choices = list("pdf","png"))
),
mainPanel(
plotOutput("graph")
)
),
downloadButton("download","Download Here")
)
server.r
library(shiny)
server <- function(input,output){
data <- function()({
switch(input$select,
"trees" = trees,
"pressure" = pressure)
})
output$graph <- renderPlot(
plot(data())
)
output$download <- downloadHandler(
filename = function(){
paste("data",input$select,input$format,sep = ".")
},
content = function(file){
if(input$format == "png")
png(file)
if(input$format == "pdf")
pdf(file)
print(plot(data()))
dev.off
}
)
}