How do I get the latlng after the dragend event in leaflet?

问题

I'm trying to update the lat/lng value of a marker after it is moved. The example provided uses a popup window to display the lat/lng.

I have a "dragend" event listener for the marker, but when I alert the value of e.latlng it returns undefined.

javascript:

function markerDrag(e){
    alert("You dragged to: " + e.latlng);
}

function initialize() {
    // Initialize the map
    var map = L.map('map').setView([38.487, -75.641], 8);
    L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
        attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>',
        maxZoom: 18
    }).addTo(map);

    // Event Handlers
    map.on('click', function(e){
        var marker = new L.Marker(e.latlng, {draggable:true});
        marker.bindPopup("<strong>"+e.latlng+"</strong>").addTo(map);

        marker.on('dragend', markerDrag);
    });
}


$(document).ready(initialize());

http://jsfiddle.net/rhewitt/Msrpq/4/

回答1:

latlng value is not in e.latlng but in e.target._latlng . Use console.

回答2:

Use e.target.getLatLng() to get the latlng of the updated position.

    // Script for adding marker on map click
    function onMapClick(e) {

        var marker = L.marker(e.latlng, {
                 draggable:true,
                 title:"Resource location",
                 alt:"Resource Location",
                 riseOnHover:true
                }).addTo(map)
                  .bindPopup(e.latlng.toString()).openPopup();

        // #12 : Update marker popup content on changing it's position
        marker.on("dragend",function(e){

            var chagedPos = e.target.getLatLng();
            this.bindPopup(chagedPos.toString()).openPopup();

        });
    }

JSFiddle demo

回答3:

While using e.target._latlng works (as proposed by this other answer), it's better practice to use

e.target.getLatLng();

That way we're not exposing any private variables, as is recommended by Leaflet:

Private properties and methods start with an underscore (_). This doesn’t make them private, just recommends developers not to use them directly.

回答4:

I think the API changed.

Nowadays is: const { lat, lng } = e.target.getCenter();

来源：https://stackoverflow.com/questions/18382945/how-do-i-get-the-latlng-after-the-dragend-event-in-leaflet

标签

event-handling

leaflet