使用传单中的 map_click 选择多个项目，链接到闪亮应用程序 (R) 中的 selectizeInput()

Question

我想创建一个传单地图，您可以在其中选择多个多边形，这将在闪亮的应用程序中更新selectizeInput()。这将包括删除选定的多边形，当它在selectizeInput() 中被删除时。

我略微更改/更新了the code from the answer here（使用 sf 而不是 sp 和更多 dplyr，我可以在其中计算出基本 R 是什么）。

多边形可能会使用与input$clicked_locations 绑定的observeEvent 进行更新，但不确定具体如何。

代码如下：

library(shiny)
library(leaflet)
library(sf)
library(dplyr)

#load shapefile
nc <- st_read(system.file("shape/nc.shp", package="sf")) %>%
  st_transform(4326)

shinyApp(
  ui = fluidPage(
    
    "Update selectize input by clicking on the map",
    
    leafletOutput("map"),
    "I would like the selectize input to update to show all the locations clicked,",
    "but also when items are removed here, they are removed on the map too, so linked to the map.",
    selectizeInput(inputId = "clicked_locations",
                   label = "Clicked",
                   choices = nc$NAME,
                   selected = NULL,
                   multiple = TRUE)
  ),
  
  server <- function(input, output, session){
    
    #create empty vector to hold all click ids
    clicked_ids <- reactiveValues(ids = vector())
    
    #initial map output
    output$map <- renderLeaflet({
      leaflet() %>%
        addTiles() %>%
        addPolygons(data = nc,
                    fillColor = "white",
                    fillOpacity = 0.5,
                    color = "black",
                    stroke = TRUE,
                    weight = 1,
                    layerId = ~NAME,
                    group = "regions",
                    label = ~NAME)
    }) #END RENDER LEAFLET
    
    observeEvent(input$map_shape_click, {
      
      #create object for clicked polygon
      click <- input$map_shape_click
      
      #define leaflet proxy for second regional level map
      proxy <- leafletProxy("map")
      
      #append all click ids in empty vector
      clicked_ids$ids <- c(clicked_ids$ids, click$id) # name when clicked, id when unclicked
      
      #shapefile with all clicked polygons - original shapefile subsetted by all admin names from the click list
      clicked_polys <- nc %>%
        filter(NAME %in% clicked_ids$ids)
      
      #if the current click ID [from CNTY_ID] exists in the clicked polygon (if it has been clicked twice)
      if(click$id %in% clicked_polys$CNTY_ID){
        
        #define vector that subsets NAME that matches CNTY_ID click ID - needs to be different to above
        name_match <- clicked_polys$NAME[clicked_polys$CNTY_ID == click$id]
        
        #remove the current click$id AND its name match from the clicked_polys shapefile
        clicked_ids$ids <- clicked_ids$ids[!clicked_ids$ids %in% click$id]
        clicked_ids$ids <- clicked_ids$ids[!clicked_ids$ids %in% name_match]
        
        # just to see
        print(clicked_ids$ids)
        
        # update
        updateSelectizeInput(session,
                             inputId = "clicked_locations",
                             label = "",
                             choices = nc$NAME,
                             selected = clicked_ids$ids)
        
        #remove that highlighted polygon from the map
        proxy %>% removeShape(layerId = click$id)
        
      } else {
        
        #map highlighted polygons
        proxy %>% addPolygons(data = clicked_polys,
                              fillColor = "red",
                              fillOpacity = 0.5,
                              weight = 1,
                              color = "black",
                              stroke = TRUE,
                              layerId = clicked_polys$CNTY_ID)
        
        # just to see
        print(clicked_ids$ids)
        
        # update
        updateSelectizeInput(session,
                             inputId = "clicked_locations",
                             label = "",
                             choices = nc$NAME,
                             selected = clicked_ids$ids)
        
      } #END CONDITIONAL
    }) #END OBSERVE EVENT
  }) #END SHINYAPP

这也发布在here 中，您还可以从答案（最初是sp 数据集）中找到代码的编辑版本，这是有效的。 nc 数据集的这段代码对我来说似乎是一样的，但似乎不起作用，尽管基于 selectizeInput() 更新多边形不在那里。

对此有什么想法吗？

Answer 1

请参阅以下解决方法：

我在渲染地图和隐藏红色叠加层时添加了所有多边形。此外，每个红色多边形都分配给它自己的组。单击相应的组，因此显示/隐藏多边形。

library(shiny)
library(leaflet)
library(sf)
library(dplyr)

#load shapefile
nc <- st_read(system.file("shape/nc.shp", package="sf")) %>%
  st_transform(4326)

shinyApp(
  ui = fluidPage(
    
    "Update selectize input by clicking on the map",
    
    leafletOutput("map"),
    "I would like the selectize input to update to show all the locations selected,",
    "but also when items are removed here, they are removed on the map too, so linked to the map.",
    selectizeInput(inputId = "selected_locations",
                   label = "selected",
                   choices = nc$NAME,
                   selected = NULL,
                   multiple = TRUE)
  ),
  
  server <- function(input, output, session){
    
    #create empty vector to hold all click ids
    selected_ids <- reactiveValues(ids = vector())
    
    #initial map output
    output$map <- renderLeaflet({
      leaflet() %>%
        addTiles() %>%
        addPolygons(data = nc,
                    fillColor = "white",
                    fillOpacity = 0.5,
                    color = "black",
                    stroke = TRUE,
                    weight = 1,
                    layerId = ~NAME,
                    group = "regions",
                    label = ~NAME) %>%
        addPolygons(data = nc,
                    fillColor = "red",
                    fillOpacity = 0.5,
                    weight = 1,
                    color = "black",
                    stroke = TRUE,
                    layerId = ~CNTY_ID,
                    group = ~NAME) %>%
        hideGroup(group = nc$NAME) # nc$CNTY_ID
    }) #END RENDER LEAFLET
    
    #define leaflet proxy for second regional level map
    proxy <- leafletProxy("map")
    
    #create empty vector to hold all click ids
    selected <- reactiveValues(groups = vector())
    
    observeEvent(input$map_shape_click, {
      if(input$map_shape_click$group == "regions"){
        selected$groups <- c(selected$groups, input$map_shape_click$id)
        proxy %>% showGroup(group = input$map_shape_click$id)
      } else {
        selected$groups <- setdiff(selected$groups, input$map_shape_click$group)
        proxy %>% hideGroup(group = input$map_shape_click$group)
      }
      updateSelectizeInput(session,
                           inputId = "selected_locations",
                           label = "",
                           choices = nc$NAME,
                           selected = selected$groups)
    })
    
    observeEvent(input$selected_locations, {
      removed_via_selectInput <- setdiff(selected$groups, input$selected_locations)
      added_via_selectInput <- setdiff(input$selected_locations, selected$groups)
      
      if(length(removed_via_selectInput) > 0){
        selected$groups <- input$selected_locations
        proxy %>% hideGroup(group = removed_via_selectInput)
      }
      
      if(length(added_via_selectInput) > 0){
        selected$groups <- input$selected_locations
        proxy %>% showGroup(group = added_via_selectInput)
      }
    }, ignoreNULL = FALSE)
    
  })

---

编辑：关于您适应 this answer 的初始方法，您需要将 layerId 传递为 character 以使事情再次正常运行：

    proxy %>% removeShape(layerId = as.character(click$id))
    
    proxy %>% addPolygons(data = clicked_polys,
                          fillColor = "red",
                          fillOpacity = 0.5,
                          weight = 1,
                          color = "black",
                          stroke = TRUE,
                          layerId = as.character(clicked_polys$CNTY_ID))

我提交了issue regarding this。

但是，我仍然更喜欢上面的显示/隐藏方法，因为我猜它比添加和删除多边形更高效。