Marker on Google Map added only once.

Question

I have the following code:

function clicked(overlay, latlng) {
  var icon3 = new GIcon();
  icon3.image = "marker.png";  
  icon3.iconAnchor = new GPoint(15, 40);

  var marker2 = new GMarker(latlng, {  icon: icon3, draggable: true,   title: 'Drag me'  });
   map.addOverlay(marker2);

}

Each time I click on the map a new marker is placed on the map. The problem is that I need only one marker and if I click several times, each time a new marker is added. How to change the code so only one marker is placed and when the map is clicked again it just changes its location?

Answer 1

You will need to implement some sort of check to see if the marker has already been placed. One option would be to keep a list of markers already added and check that list for a marker at a specific point before calling the functions to add the marker to the map. If you need a code sample, let me know.

Answer 2

I would recommend keeping an instance of marker2 outside of the clicked function, then if marker2 is null, make and add a new one like you are now, otherwise call marker2.setLatLong(latlng); to update it's location.

Untested example code:

var marker2;

function clicked(overlay, latlng) {
  if (marker2 == null) {
    var icon3 = new GIcon();
    icon3.image = "marker.png";  
    icon3.iconAnchor = new GPoint(15, 40);

    marker2 = new GMarker(latlng, {  icon: icon3, draggable: true,   title: 'Drag me'  });
    map.addOverlay(marker2);
  }
  else {
    marker2.setLatLong(latlng);
  }
}

Answer 3

I think that it should test if marker2 is null and if not, removeOverlay(marker2) and add new one.

Answer 4

Well, dont bother, I figured it out myself. I just used map.clearOverlays(); before the marker is pplaced and that solved the problem.