我有一个闪亮的应用程序，允许用户根据加载的数据框选择在x和y轴上绘制的内容。我试图让用户下载当前的情节视图。我正在谷歌Chrome中启动应用程序，因为我知道如果应用程序在R studio中启动，它无法保存文件。截至目前，它保存了一个png文件，但它是空白的。
http://docs.geotools.org/stable/userguide/library/referencing/calculator.html
我已使用这些帖子尝试解决此问题：
Screenshot of app UI can be seen here
Downloading png from Shiny (R)
如果vis()更改为函数而不是被动，则该应用无效。但是，当filteredData()从被动变为函数时，应用仍然可以正常工作。但是，如果在downloadHandler(... vis() filteredData()，print(filteredData())或print(vis())范围内，则仍会产生空白png。如果使用#Check packages to use in library
library('shiny') #allows for the shiny app to be used
library('stringr') #string opperator
library('ggvis') #allows for interactive ploting
library('dplyr')
alldata <- iris
#establish options for drop down menus
specieschoices <- unique(as.character(alldata$Species))
petalwchoices <- unique(as.character(alldata$Petal.Width))
petallchoices <- unique(as.character(alldata$Petal.Length))
sepallchoices <- unique(as.character(alldata$Sepal.Length))
sepalwchoices <- unique(as.character(alldata$Sepal.Width))
# UI
ui<-fluidPage(
titlePanel("Explorer"),
fluidRow(
column(4,
wellPanel(
h4("Apply Filters"),
selectInput(inputId = "species", label="Select a Species:", choices = sort(specieschoices), selected="setosa", multiple = TRUE, selectize = TRUE),
selectInput(inputId = "petalw", label="Select Petal Width:", choices = sort(petalwchoices), selected=petalwchoices, multiple = TRUE, selectize = FALSE),
selectInput(inputId = "petall", label="Select Petal Length", choices = sort(petallchoices), selected=petallchoices, multiple = TRUE, selectize = FALSE),
selectInput(inputId = "sepall", label="Select Sepal Length", choices = sort(sepallchoices), selected=sepallchoices, multiple = TRUE, selectize = FALSE),
selectInput(inputId = "sepalw", label="Select Sepal Width", choices = sort(sepalwchoices), selected=sepalwchoices, multiple = TRUE, selectize = FALSE),
downloadButton('downloadPlot', 'Download Plot')
)),
column(8,
ggvisOutput("plot1")
),
column(4,
wellPanel(
h4("Data Variables"),
selectInput(inputId = "x", label="Select x-axis Variable:", choices=as.character(names(alldata[,1:4])),selected='Petal.Length', multiple = FALSE),
selectInput(inputId = "y", label="Select y-axis Variable:", choices=as.character(names(alldata[,1:4])),selected='Petal.Width', multiple = FALSE)
))
))
#SERVER
server<-function(input,output,session)
{
#Set up reactive variables
filteredData <- reactive({
# Apply filters
m <- alldata %>% filter(
`Species` %in% input$species,
`Petal.Width` %in% input$petalw,
`Petal.Length` %in% input$petall,
`Sepal.Width` %in% input$sepalw,
`Sepal.Length` %in% input$sepall
)
m <- droplevels(as.data.frame(m))
m
})
vis <- reactive({
xvar <- prop("x", as.symbol(input$x))
yvar <- prop("y", as.symbol(input$y))
p1 = filteredData() %>%
ggvis(x = xvar, y = yvar) %>%
layer_points(size.hover := 200,
fillOpacity:= 0.5, fillOpacity.hover := 1,
fill = ~Species
)
})
#Actually plots the data
vis %>% bind_shiny("plot1")
################# THIS IS THE PART THAT I NEED HELP WITH#####################
output$downloadPlot <- downloadHandler(
filename = paste0(input$y, '_vs_', input$x, "_", Sys.Date(), ".png"),
content = function(file) {
png(file)
vis()
dev.off()
},
contentType = 'image/png'
)
##############################################################################
}
#Run the Shiny App to Display Webpage
shinyApp(ui=ui, server=server)
，则会在浏览器中弹出另一个窗口，其中显示＆＃34; Key /已在使用＆＃34;。下面是复制问题的最小工作代码，非常感谢您提供的任何帮助。
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答案 0 :(得分：0)
我通过创建另一个创建ggplot图的函数解决了这个问题，该图是我用ggvis图完全复制的，用于downloadHandler。