我正在用谷歌的方式在一个闪亮的应用程序。
我从这个例子开始：在R中使用传单绘制旅程路径，并对其进行了少许修改，以包括目的地和起源地之间的2个额外的航点，并让google_directions渲染它们之间的最佳路线。
绘制的路线确实是最佳的，我能够复制这5-6-7或10个航点。然而，在每种情况下，要绘制路线，我需要把地址的所有航路点。如果一些航点留空，应用程序会返回错误，我不知道如何解决这个问题。我想应该使用某种“如果”运算符，但不确定如何以及在哪里使用。
这是我的代码：

library(shiny)
library(googleway)

ui <- navbarPage("APP NAME", position = c("static-top"),
tabPanel("MAP",
       google_mapOutput(outputId = "mapWarsaw"),
       textInput(inputId = "origin", label = "Departure point"
       ),
       textInput(inputId = "waypoint", label = "Waypoint 1"
       ),
       textInput(inputId = "waypoint2", label = "Waypoint 2",
       ),
       textInput(inputId = "destination", label = "Destination point"
       ),
       actionButton(inputId = "getRoute", label = "Get Route")
       )
)

server <- function(input, output, session) {

map_key <- '<APIKEY>'
api_key <- '<APIKEY>'

df_route <- eventReactive(input$getRoute,{

print("getting route")

o <- input$origin
w <- input$waypoint
q <- input$waypoint2
d <- input$destination

return(data.frame(origin = o, waypoint = w, waypoint2 = q, destination = d, stringsAsFactors = F))

})

output$mapWarsaw <- renderGoogle_map({
df <- df_route()
print(df)
if(df$origin == "" | df$waypoint == ""| df$waypoint2 == "" | df$destination == "")
  return()

res <- google_directions(key = api_key,
                         origin = df$origin,
                         waypoints = list(stop = df$waypoint,
                                          stop = df$waypoint2),
                         destination = df$destination,
                         optimise_waypoints = TRUE,
                         mode = "driving")

df_route <- data.frame(route = res$routes$overview_polyline$points)

google_map(key = map_key, search_box = TRUE, scale_control = TRUE, height = 1000) %>%
  add_traffic()%>%
  add_polylines(data = df_route,
                polyline = "route",
                stroke_colour = "#FF33D6",
                stroke_weight = 7,
                stroke_opacity = 0.7,
                info_window = "New route",
                load_interval = 100)
})
}

shinyApp(ui, server)

数据文件：

popupcontent;label;lat;lng          
Location 1;Location Label 1;52.2572126;20.9845778   
Location 2;Location Label 2;52.2423875;21.0244197   
Location 3;Location Label 3;52.238209;21.0202826    
Location 4;Location Label 4;52.23048060000001;21.0108891
Location 5;Location Label 5;52.231755;21.006482 
Location 6;Location Label 6;52.2376719;21.0158829A7 
Location 7;Location Label 7;52.2540379;21.0347079   
Location 8;Location Label 8;52.2550605;21.052299    
Location 9;Location Label 9;52.247861;21.049922 
Location 10;Location Label 10;52.2720819;21.0151038
Location 11;Location Label 11;52.2582368;21.0396915
Location 12;Location Label 12;52.2569792;21.0294134
Location 13;Location Label 13;52.2549106;21.0475752
Location 14;Location Label 14;52.206521;20.999852   
Location 15;Location Label 15;52.2937449;21.0333861
Location 16;Location Label 16;52.2878479;21.0412171
Location 17;Location Label 17;52.305039;21.0584014