r - clearShapes() 不起作用——R 的 leaflet()

Question

我不明白为什么 clearshapes() 在我的传单 Shiny 程序中不起作用。我正在尝试删除现有的圆圈并替换为根据我拥有的输入复选框选择的类别。然而，发生的情况是新的圆圈叠加在现有的圆圈之上。

有人遇到过这种情况吗？

df = read.csv("mappingData.csv",header=T, sep =",")

ui = fluidPage(
  checkboxGroupInput("set", label = "Pothole Reported by:",
                     choices = list("Citizens Connect App" = "Citizens Connect App", 
                                    "City Worker App" = "City Worker App",
                                    "Constituent Call" = "Constituent Call",
                                    "Self Service" = "Self Service",
                                    "Employee Generated" = "Employee Generated",
                                    "Not Available (Cambridge)" = "")),

  verbatimTextOutput("value"),

  leafletOutput("map")
)


server <- function(input, output) {

  filteredDataCheck <- reactive({
    # subset(df, Source == input$set)
    print(input$set)
  })

  output$value <- renderPrint ({ filteredDataCheck() })

  filteredData <- reactive({
    df[as.character(df$Source) == input$set, ]
  })


  output$map <- renderLeaflet ({
    leaflet(df) %>%
      setView(-71.083, 42.353, 13) %>%
     addProviderTiles("Stamen.TonerLite", options = providerTileOptions(noWrap=T))
  })

  observe({
    leafletProxy("map", data = filteredData() ) %>% clearShapes() %>%
      addCircles(radius = 1, color = "red", group = "circles") %>% clearShapes()

  })

}

shinyApp(ui = ui, server = server)

Answer 1

当 filteredData() 为空时，似乎存在问题。您可以尝试添加 if/else:

if(nrow(filteredData())==0) { leafletProxy("map") %>% clearShapes()} 
else {
    leafletProxy("map", data = filteredData() ) %>% clearShapes() %>%
      addCircles(radius = 1, color = "red", group = "circles")
    }

此外，如果您想要具有选定源的所有数据点，您可能需要使用%in%而不是==在您的过滤中:

df[as.character(df$Source) %in% input$set, ]