r閃亮的傳單 - 按需創建彈出窗口

Question

在addCirclemarkers中插入彈出窗口導致需要映射數千個點的數據的冗長計算時間。我假設在顯示地圖之前必須計算所有彈出窗口。

我在網上搜索了一種方法，只點擊點/圓/標記就可以添加/創建彈出窗口。目前，我在下面的代碼。如果運行此代碼，您將看到彈出窗口已創建，但未從數據中提取字符串。我究竟做錯了什麼？

library(shiny) 
library(leaflet) 
library(htmltools) 
library(sp) 

data <- data.frame(
    "name"=c("Place 1","Place 2","Place 3"), 
    "lat"=c(50,51,52), 
    "lng"=c(3,4,5), stringsAsFactors = FALSE) 

ui = fluidPage(
    fluidRow(column(8, offset = 2, leafletOutput("map", width = "100%", height = "650px"))) 
)        

server = function(input, output, session) { 

    pts <- reactive({ 
    pts <- data 
    coordinates(pts) <- ~lng+lat 
    pts 
    }) 

    output$map <- renderLeaflet({ 
    leaflet(pts()) %>% 
     addTiles(group="OSM") %>% 
     addCircleMarkers() 
    }) 

    observeEvent(input$map_marker_click, { 
    leafletProxy("map") %>% clearPopups() 
    event <- input$map_marker_click 
    if (is.null(event)) 
     return() 
    isolate({ 
     pts2 <- pts() 
     sgh <- pts2[row.names(pts2) == event$id,] 
     # sgh <- pts2[pts2$name == event$id,] 
     content <- htmlEscape(paste("This place is",as.character(sgh$name))) 
     leafletProxy("map") %>% addPopups(event$lng, event$lat, content, layerId = event$id) 
    }) 
    }) 

} 

shinyApp(ui = ui, server = server, options = list(launch.browser=TRUE)) 

Answer 1

有了你的代碼event$id是NULL，所以sgh <- pts2[row.names(pts2) == event$id,]線返回NULL爲好。

你必須在layerId添加到CircleMarkers（而沒有必要將其添加到Popup
這也讓訪問它wothout需要對「合併」它與原始數據：

output$map <- renderLeaflet({ 
    leaflet(pts()) %>% 
     addTiles(group="OSM") %>% 
     addCircleMarkers(layerId = ~name) 
}) 

observeEvent(input$map_marker_click, { 
    leafletProxy("map") %>% 
     clearPopups() 
    event <- input$map_marker_click 
    if (is.null(event)) 
     return() 
    isolate({ 
     content <- htmlEscape(paste("This place is", event$id)) 

     leafletProxy("map") %>% 
      addPopups(event$lng, event$lat, content) 
    }) 
})