使Leaflet图层可单击或不可点击而无需重新排序

Question

在SO或Google中找不到答案，然后我自己成功找到解决方案，我决定同时提出问题并立即回答。

可以在“答案”中找到可重现的代码。

问题

默认情况下，所有图层都是“可点击的”。因此，当使用多个图层时，特别是在覆盖另一个图层时（例如标记和多边形），图层的顺序决定了可点击的内容。覆盖多边形的标记将保持不可点，即使多边形没有弹出标签。

我发现谈论此问题的唯一帖子是：Leaflet Map - second Polygon makes the first layer unclickable

天真的解决方案是确保标记最后分层。不幸的是，如果您使用addLayersControl()之类的功能，启用/禁用图层会将该图层移到前面。因此，虽然图层顺序最初 ，但它并没有真正“解决”问题。

Answer 1

解决方案

相应地使用功能pathOptions()，markerOptions()和labelOptions()。

就我而言，导致问题的是多边形图层。通过执行addPolygons(..., options = pathOptions(clickable = FALSE))使这些“无法点击”。

实施例

library(rgdal) # for spatial data
library(leaflet)
library(dplyr)
library(magrittr)

# download and load state border data
url <- "http://www2.census.gov/geo/tiger/GENZ2015/shp/cb_2015_us_state_5m.zip"
temp <- tempfile(fileext = '.zip')
download.file(url, temp)
unzip(temp, exdir = dirname(temp))
states <- rgdal::readOGR(file.path(dirname(temp), "cb_2015_us_state_5m.shp"),
  layer = "cb_2015_us_state_5m", verbose = FALSE)
unlink(temp)

# code adopted from https://rstudio.github.io/leaflet/shapes.html
neStates <- subset(states, states$STUSPS %in% c(
  "CT","ME","MA","NH","RI","VT","NY","NJ","PA"
))

cities <- read.csv(textConnection("
City,Lat,Long,Pop
Boston,42.3601,-71.0589,645966
Hartford,41.7627,-72.6743,125017
New York City,40.7127,-74.0059,8406000
Philadelphia,39.9500,-75.1667,1553000
Pittsburgh,40.4397,-79.9764,305841
Providence,41.8236,-71.4222,177994
"))


# (1) polygon layer added last; cannot click cities/circles
map_1 <- leaflet(neStates) %>%
  addProviderTiles("CartoDB.Positron") %>%
  addCircles(data = cities, lng = ~Long, lat = ~Lat, weight = 1,
    radius = ~sqrt(Pop) * 30, popup = ~City,
    group = "Cities") %>%
  addPolygons(
    stroke = FALSE, fillOpacity = 0.2, smoothFactor = 0.5,
    color = ~colorQuantile("YlOrRd", states$AWATER)(AWATER),
    group = "States") %>%
  addLayersControl(overlayGroups = c('Cities', 'States'),
    options = layersControlOptions(collapsed = FALSE))


# (2) polygon layer made 'unclickable' (clickable = FALSE)
map_2 <- leaflet(neStates) %>%
  addProviderTiles("CartoDB.Positron") %>%
  addCircles(data = cities, lng = ~Long, lat = ~Lat, weight = 1,
    radius = ~sqrt(Pop) * 30, popup = ~City,
    group = "Cities") %>%
  addPolygons(
    stroke = FALSE, fillOpacity = 0.2, smoothFactor = 0.5,
    color = ~colorQuantile("YlOrRd", states$AWATER)(AWATER),
    group = "States",
    options = pathOptions(clickable = FALSE)) %>% # DISABLE 'clickable'
  addLayersControl(overlayGroups = c('Cities', 'States'),
    options = layersControlOptions(collapsed = FALSE))


map_1 # even if polygon layer is put last, disable/enable layer puts it in front again
map_2 # disable/enabling any layer has no impact!