在leaflet/shiny中选择和取消选择多边形时,可以通过监听双击事件和单击事件来实现样式的更改。以下是一个可能的解决方案:
dblclick
事件监听器,当双击多边形时触发回调函数。click
事件监听器,当单击多边形时触发回调函数。请注意,具体的代码实现取决于Leaflet和Shiny的版本和用法。以下是一个简单示例代码:
library(leaflet)
library(shiny)
# 创建Leaflet地图
map <- leaflet() %>%
addTiles() %>%
setView(lng = 0, lat = 0, zoom = 2)
# 创建多边形图层
polygon <- leaflet::addPolygons(
map = map,
lng = c(-10, 10, 10, -10),
lat = c(-10, -10, 10, 10)
)
# Shiny应用程序
shinyApp(
ui = fluidPage(
leafletOutput("mapOutput")
),
server = function(input, output, session) {
output$mapOutput <- renderLeaflet({
map
})
# 双击事件
observeEvent(input$mapOutput_shape_dblclick, {
# 获取多边形ID
shape_id <- input$mapOutput_shape_dblclick$id
# 根据ID找到多边形图层并更改样式
leaflet::leafletProxy("mapOutput") %>%
leaflet::addIdMarker(
id = shape_id,
lat = 0,
lng = 0,
label = paste("Double Clicked Shape ID:", shape_id),
popup = "Double Clicked!",
icon = leaflet::makeIcon(
iconUrl = "http://leafletjs.com/examples/custom-icons/leaf-green.png",
iconSize = c(38, 95),
iconAnchor = c(22, 94),
popupAnchor = c(-3, -76),
shadowUrl = "http://leafletjs.com/examples/custom-icons/leaf-shadow.png",
shadowSize = c(50, 64),
shadowAnchor = c(4, 62)
)
)
})
# 单击事件
click_count <- reactiveValues(count = 0)
observeEvent(input$mapOutput_shape_click, {
click_count$count <- click_count$count + 1
if (click_count$count == 2) {
# 获取多边形ID
shape_id <- input$mapOutput_shape_click$id
# 根据ID找到多边形图层并更改样式
leaflet::leafletProxy("mapOutput") %>%
leaflet::removeMarker(shape_id) # 移除之前双击添加的标记
leaflet::leafletProxy("mapOutput") %>%
leaflet::addCircleMarker(
lat = 0,
lng = 0,
radius = 10,
color = "red",
popup = "Double Clicked!"
)
} else if (click_count$count == 3) {
# 获取多边形ID
shape_id <- input$mapOutput_shape_click$id
# 根据ID找到多边形图层并更改样式
leaflet::leafletProxy("mapOutput") %>%
leaflet::removeMarker(shape_id) # 移除之前双击添加的标记
leaflet::leafletProxy("mapOutput") %>%
leaflet::addCircleMarker(
lat = 0,
lng = 0,
radius = 10,
color = "blue",
popup = "Triple Clicked!"
)
click_count$count <- 0 # 重置计数器
}
})
}
)
上述代码示例中,双击多边形时将添加一个绿色的标记,双击后将更换成红色的圆圈标记,三次单击后将更换成蓝色的圆圈标记。你可以根据实际需求自定义样式和行为。
领取专属 10元无门槛券
手把手带您无忧上云