Javascript Google Maps Api v3 - getBounds 未定义
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Google Maps Api v3 - getBounds is undefined
提问by DolceVita
I'm switching from v2 to v3 google maps api and got a problem with gMap.getBounds()function.
我正在从 v2 切换到 v3 google maps api，但gMap.getBounds()功能出现问题。
I need to get the bounds of my map after its initialization.
我需要在初始化后获取地图的边界。
Here is my javascript code:
这是我的 javascript 代码：
var gMap;
$(document).ready(
function() {
var latlng = new google.maps.LatLng(55.755327, 37.622166);
var myOptions = {
zoom: 12,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
gMap = new google.maps.Map(document.getElementById("GoogleMapControl"), myOptions);
alert(gMap.getBounds());
}
);
So now it alerts me that gMap.getBounds()is undefined.
所以现在它提醒我这gMap.getBounds()是未定义的。
I've tried to get getBounds values in click event and it works fine for me, but I cannot get the same results in load map event.
我试图在 click 事件中获取 getBounds 值，它对我来说很好用，但我无法在加载地图事件中获得相同的结果。
Also getBounds works fine while document is loading in Google Maps API v2, but it fails in V3.
在 Google Maps API v2 中加载文档时，getBounds 也能正常工作，但在 V3 中失败。
Could you please help me to solve this problem?
你能帮我解决这个问题吗？
回答by Daniel Vassallo
In the early days of the v3 API, the getBounds()method required the map tiles to have finished loading for it to return correct results. However now it seems that you can listen to bounds_changedevent, which is fired even before the tilesloadedevent:
在 v3 API 的早期，该getBounds()方法要求地图图块已完成加载才能返回正确的结果。但是现在看来您可以收听bounds_changed事件，该事件甚至在tilesloaded事件发生之前就被触发：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<title>Google Maps v3 - getBounds is undefined</title>
<script src="http://maps.google.com/maps/api/js?sensor=false"
type="text/javascript"></script>
</head>
<body>
<div id="map" style="width: 500px; height: 350px;"></div>
<script type="text/javascript">
var map = new google.maps.Map(document.getElementById("map"), {
zoom: 12,
center: new google.maps.LatLng(55.755327, 37.622166),
mapTypeId: google.maps.MapTypeId.ROADMAP
});
google.maps.event.addListener(map, 'bounds_changed', function() {
alert(map.getBounds());
});
</script>
</body>
</html>
回答by Salman A
It should be working, atleast according to the documentation for getBounds(). Nevertheless:
它应该可以工作，至少根据 getBounds() 的文档。尽管如此：
var gMap;
$(document).ready(function() {
var latlng = new google.maps.LatLng(55.755327, 37.622166);
var myOptions = {
zoom: 12,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
gMap = new google.maps.Map(document.getElementById("GoogleMapControl"), myOptions);
google.maps.event.addListenerOnce(gMap, 'idle', function(){
alert(this.getBounds());
});
});
See it working here.
看到它在这里工作。
回答by treznik
I was saying Salman's solution is better because the idleevent is called earlier than the tilesloadedone, since it waits for all the tiles to be loaded. But on a closer look, it seems bounds_changedis called even earlier and it also makes more sense, since you're looking for the bounds, right? :)
我是说 Salman 的解决方案更好，因为该idle事件的调用时间早于该事件tilesloaded，因为它会等待所有图块加载完毕。但仔细观察，它似乎bounds_changed被调用得更早，也更有意义，因为您正在寻找界限，对吧？:)
So my solution would be:
所以我的解决方案是：
google.maps.event.addListenerOnce(gMap, 'bounds_changed', function(){
alert(this.getBounds());
});
回答by Almer
In other comments here, it's adviced to use the "bounds_changed" event over "idle", which I agree with. Certainly under IE8 which triggers "idle" before "bounds_changed" on my dev machine at least, leaving me with a reference to null on getBounds.
在这里的其他评论中，建议在“空闲”上使用“bounds_changed”事件，我同意这一点。当然，在 IE8 下，它至少在我的开发机器上的“bounds_changed”之前触发“idle”，让我在 getBounds 上引用 null。
The "bounds_changed" event however, will be triggered continuously when you'll drag the map. Therefor, if you want to use this event to start loading markers, it will be heavy on your webserver.
但是，当您拖动地图时，“bounds_changed”事件将连续触发。因此，如果你想使用这个事件来开始加载标记，你的网络服务器会很重。
My multi browser solution to this problem:
我对这个问题的多浏览器解决方案：
google.maps.event.addListenerOnce(gmap, "bounds_changed", function(){
loadMyMarkers();
google.maps.event.addListener(gmap, "idle", loadMyMarkers);
});
回答by Fernando
Well, i'm not sure if i'm too late, but here's my solution using gmaps.jsplugin:
好吧，我不确定我是否为时已晚，但这是我使用gmaps.js插件的解决方案：
map = new GMaps({...});
// bounds loaded? if not try again after 0.5 sec
var check_bounds = function(){
var ok = true;
if (map.getBounds() === undefined)
ok = false;
if (! ok)
setTimeout(check_bounds, 500);
else {
//ok to query bounds here
var bounds = map.getBounds();
}
}
//call it
check_bounds();
