google maps 如何显示文字或者数字，且为动态的
如题：
google maps 如何根据经纬度显示文字或者数字，且为动态的。（JavaScript实现）
例：根据给定经纬度，显示一些数字，并且这些数字是动态显示的，每3s或者其他时间显示不同数据！
[解决办法]
显示自定义文本/图片的话，你需要创建一个自定义的覆盖层。给你一个改编自官方谷歌文档的例子，你自己参考一下吧。
//adapded from this example http://code.google.com/apis/maps/documentation/javascript/overlays.html#CustomOverlays
//text overlays
function TxtOverlay(pos, txt, cls, map){
// Now initialize all properties.
this.pos = pos;
this.txt_ = txt;
this.cls_ = cls;
this.map_ = map;
// We define a property to hold the image's
// div. We'll actually create this div
// upon receipt of the add() method so we'll
// leave it null for now.
this.div_ = null;
// Explicitly call setMap() on this overlay
this.setMap(map);
}
TxtOverlay.prototype = new google.maps.OverlayView();
TxtOverlay.prototype.onAdd = function(){
// Note: an overlay's receipt of onAdd() indicates that
// the map's panes are now available for attaching
// the overlay to the map via the DOM.
// Create the DIV and set some basic attributes.
var div = document.createElement('DIV');
div.className = this.cls_;
div.innerHTML = this.txt_;
// Set the overlay's div_ property to this DIV
this.div_ = div;
var overlayProjection = this.getProjection();
var position = overlayProjection.fromLatLngToDivPixel(this.pos);
div.style.left = position.x + 'px';
div.style.top = position.y + 'px';
// We add an overlay to a map via one of the map's panes.
var panes = this.getPanes();
panes.floatPane.appendChild(div);
}
TxtOverlay.prototype.draw = function(){
var overlayProjection = this.getProjection();
// Retrieve the southwest and northeast coordinates of this overlay
// in latlngs and convert them to pixels coordinates.
// We'll use these coordinates to resize the DIV.
var position = overlayProjection.fromLatLngToDivPixel(this.pos);
var div = this.div_;
div.style.left = position.x + 'px';
div.style.top = position.y + 'px';
}
//Optional: helper methods for removing and toggling the text overlay.
TxtOverlay.prototype.onRemove = function(){
this.div_.parentNode.removeChild(this.div_);
this.div_ = null;
}
TxtOverlay.prototype.hide = function(){
if (this.div_) {
this.div_.style.visibility = "hidden";
}
}
TxtOverlay.prototype.show = function(){
if (this.div_) {
this.div_.style.visibility = "visible";
}
}
TxtOverlay.prototype.toggle = function(){
if (this.div_) {
if (this.div_.style.visibility == "hidden") {
this.show();
}
else {
this.hide();
}
}
}
TxtOverlay.prototype.toggleDOM = function(){
if (this.getMap()) {
this.setMap(null);
}
else {
this.setMap(this.map_);
}
}
var map;
function init(){
var latlng = new google.maps.LatLng(37.9069, -122.0792);
var myOptions = {
zoom: 4,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById("map"), myOptions);
var marker = new google.maps.Marker({
position: latlng,
map: map,
title: "Hello World!"
});
customTxt = "<div>Blah blah sdfsddddddddddddddd ddddddddddddddddddddd<ul><li>Blah 1<li>blah 2 </ul></div>"
txt = new TxtOverlay(latlng,customTxt,"customBox",map )
}
</script>
<style>
.customBox {
background: yellow;
border: 1px solid black;
position: absolute;
}
</style>
</head>
<body onload="init()">
<div id="map" style="width: 600px; height: 600px;">
</div>
</body>
</html>
