downloadButton/ downloadHandler does not recognize filename argument
I've run into a problem with downloadHandler() in Shiny:
If I want to download any file via this function, the filename in the download window is the same as the name of the output-variable (in the example: "downloadData"), but not as it is declared in "filename=" in downloadHandler() (which should be "data-2017-02-13.csv").
Note that the following example is from the downloadHandler() - help page, so I guess there is a general problem with R or RStudio in which I write R scripts.
Additionally when I open the shiny app in a web browser, the problem vanishes.
This partially solves it, but I would still like to know why shiny is behaving differently inside RStudio and a web browser.
## Only run examples in interactive R sessions
if (interactive()) {
ui <- fluidPage(
downloadLink("downloadData", "Download")
)
server <- function(input, output) {
# Our dataset
data <- mtcars
output$downloadData <- downloadHandler(
filename = function() {
paste("data-", Sys.Date(), ".csv", sep="")
},
content = function(file) {
write.csv(data, file)
}
)
}
shinyApp(ui, server)
}
and here the download window I get: 
当我使用RStudio预览窗口时，我遇到了同样的问题，并且始终通过使用该命令打开浏览器来解决此问题
runApp(launch.browser = TRUE)