Have just one InfoWindow open in Google Maps API v3

I need to have only one InfoWindow open on my Google Map. I need to close all other InfoWindows before I open a new one.

Can someone show me how to do this?

You need to create just one InfoWindow object, keep a reference to it, and reuse if for all the markers. Quoting from the Google Maps API Docs:

If you only want one info window to display at a time (as is the behavior on Google Maps), you need only create one info window, which you can reassign to different locations or markers upon map events (such as user clicks).

Therefore, you may simply want to create the InfoWindow object just after you initialize your map, and then handle the click event handlers of your markers as follows. Let's say you have a marker called someMarker:

google.maps.event.addListener(someMarker, 'click', function() {
   infowindow.setContent('Hello World');
   infowindow.open(map, this);
});

Then the InfoWindow should automatically close when you click on a new marker without having to call the close() method.

Create your infowindow out of the scope so that you can share it.

Here is a simple example:

var markers = [AnArrayOfMarkers];
var infowindow = new google.maps.InfoWindow();

for (var i = 0, marker; marker = markers[i]; i++) {
  google.maps.event.addListener(marker, 'click', function(e) {
    infowindow.setContent('Marker position: ' + this.getPosition());
    infowindow.open(map, this);
  });
}

I had the same problem but the best answer didn't solve it completely, what I had to do in my for statement was using the this relating to my current marker. Maybe this helps someone.

for(var i = 0; i < markers.length; i++){
    name = markers[i].getAttribute("name");
    address = markers[i].getAttribute("address");        
    point = new google.maps.LatLng(parseFloat(markers[i].getAttribute("lat")), parseFloat(markers[i].getAttribute("lng")));                                     
    contentString = '<div style="font-family: Lucida Grande, Arial, sans-serif;>'+'<div><b>'+ name +'</b></div>'+'<div>'+ address +'</div>';                    
    marker = new google.maps.Marker({                       
        map: map,
        position: point,
        title: name+" "+address,
        buborek: contentString 
    });                                     
    google.maps.event.addListener(marker, 'click', function(){
        infowindow.setContent(this.buborek); 
        infowindow.open(map,this); 
    });                                                         
    marker.setMap(map);                 
}

a tad late, but I managed to have only one infowindow open by maken infowindow a global variable.

var infowindow = new google.maps.InfoWindow({});

then inside the listner

infowindow.close();
infowindow = new google.maps.InfoWindow({   
    content: '<h1>'+arrondissement+'</h1>'+ gemeentesFiltered                           
});

infowindow.open(map, this);

Declare a globar var selectedInfoWindow; and use it to hold the opened info window:

var infoWindow = new google.maps.InfoWindow({
    content: content
});

// Open the infowindow on marker click
google.maps.event.addListener(marker, "click", function() {
    //Check if there some info window selected and if is opened then close it
    if (selectedInfoWindow != null && selectedInfoWindow.getMap() != null) {
        selectedInfoWindow.close();
        //If the clicked window is the selected window, deselect it and return
        if (selectedInfoWindow == infoWindow) {
            selectedInfoWindow = null;
            return;
        }
    }
    //If arrive here, that mean you should open the new info window 
    //because is different from the selected
    selectedInfoWindow = infoWindow;
    selectedInfoWindow.open(map, marker);
});