我在PHP / MYSQL应用程序中使用谷歌地图。我得到了地图形式Goolge Docs的代码，并对应用程序进行了一些调整。 应用程序中出现了新的修改，现在应用程序需要知道“谷歌地图的当前缩放级别”。我在互联网上办理登机手续，但我找不到明确的答案。 有可能吗？是否必须在每次缩放更改时重新加载页面？ 这是代码和谢谢。
<code>
function load() {
var map = new google.maps.Map(document.getElementById("map"), {
center: new google.maps.LatLng(latitude,longitude),
zoom: zoommapa,
zoomControl: true,
zoomControlOptions: {
style: google.maps.ZoomControlStyle.LARGE
},
mapTypeId: 'roadmap'
});
// drap center
var image = 'images/icons/etapa/etapa.png';
var myLatLng = new google.maps.LatLng(latitude,longitude);
var beachMarker = new google.maps.Marker({
position: myLatLng,
map: map,
icon: image
});
var infoWindow = new google.maps.InfoWindow;
// Change this depending on the name of your PHP file
downloadUrl("marquers_motor_3.php", function(data) {
var xml = data.responseXML;
var markers = xml.documentElement.getElementsByTagName("marker");
//var name = 1;
var markers2 = [];
for (var i = 0; i < markers.length; i++) {
//var name = markers[i].getAttribute("name");
var image = markers[i].getAttribute("image");
var sombra = markers[i].getAttribute("sombra");
var address = markers[i].getAttribute("address");
var type = markers[i].getAttribute("type");
var orden = markers[i].getAttribute("order");
var name = markers[i].getAttribute("name"); // web_site email ciudad pais
var web_site = markers[i].getAttribute("web_site");
var email = markers[i].getAttribute("email");
var ciudad = markers[i].getAttribute("ciudad");
var pais = markers[i].getAttribute("pais");
var point = new google.maps.LatLng(
parseFloat(markers[i].getAttribute("lat")),
parseFloat(markers[i].getAttribute("lng")));
if (ciudad =="" || ciudad =='Desconocido') { ciudad = ""} else {ciudad =ciudad + " " }
if (!(web_site =="")) {web_site = "<a href='" + web_site + "' class='list' target='_blank'>" + web_site +"</a>"+"<br>"} else {web_site =""}
var html = "<div id='infoWindow'>" + orden + " - " + name + "<br>" + web_site + ciudad + " " + pais + "</div>";
//var name = name + 1;
var icon = customIcons[type] || {};
var marker = new google.maps.Marker({
map: map,
position: point,
icon: image,
shadow: sombra
});
var marker2 = new google.maps.Marker({
position: point
});
markers2.push(marker);
bindInfoWindow(marker, map, infoWindow, html);
}
});
var mcOptions = {gridSize: 50, maxZoom: 15};
var MarkerClusterer = new MarkerClusterer(map, markers2,mcOptions);
}
function bindInfoWindow(marker, map, infoWindow, html) {
google.maps.event.addListener(marker, 'click', function() {
infoWindow.setContent(html);
infoWindow.open(map, marker);
});
}
function downloadUrl(url, callback) {
var request = window.ActiveXObject ?
new ActiveXObject('Microsoft.XMLHTTP') :
new XMLHttpRequest;
request.onreadystatechange = function() {
if (request.readyState == 4) {
request.onreadystatechange = doNothing;
callback(request, request.status);
}
};
request.open('GET', url, true);
request.send(null);
}
function doNothing() {}
//]]>
//google.maps.event.addDomListener(window, 'load', initialize);
答案 0 :(得分：1)
我认为应用程序需要知道缩放级别，但缩放级别在用户空间（客户端）。
使用javascript从地图中获取缩放级别（请参阅https://developers.google.com/maps/documentation/javascript/reference?hl=nl#Map）
map.getZoom（）;
必须使用AJAX调用
服务器可以根据需要进行缩放级别
请记住，如果多个用户可以打开相同的地图，缩放级别可能会有所不同，那么所需的行为是什么？
答案 1 :(得分：1)
是的，您可以使用getZoom对象的google.maps.Map方法获取地图的当前缩放级别。
如果您需要在缩放更改时触发方法，则可以收听zoom_changed对象的google.maps.Map事件。有关google.maps.Map对象读取的更多信息：this
考虑以下示例（使其工作：在记事本中复制将文件另存为html并使用Chrome运行）：
<!DOCTYPE html>
<html>
<head>
<title>Getting Zoom Demo</title>
<style type="text/css">
html, body{ height: 100%; height: 100%; margin: 0; padding: 0; }
#map-container{ height: 100%; width: 100%; min-width:500px; min-height:300px; }
</style>
<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
</head>
<body>
<div>
<label id="display-zoom-label">
</label>
</div>
<div id="map-container"></div>
<script>
// Global map variable to have access to map object everywhere in the code
var map,
firstBoundChangedListener,
markers = [];
// Add random markers
function addMarkers(count) {
// map is the google.maps.Map object
var bounds = map.getBounds();
var northEast = bounds.getNorthEast();
var southWest = bounds.getSouthWest();
var minLat = Math.min(northEast.lat(), southWest.lat());
var maxLat = Math.max(northEast.lat(), southWest.lat());
var minLng = Math.min(northEast.lng(), southWest.lng());
var maxLng = Math.max(northEast.lng(), southWest.lng());
var latDifference = maxLat - minLat;
var lngDifference = maxLng - minLng;
var latLngArray = new Array();
for (var i = 0; i < count; i++) {
var lat = minLat + Math.random() * latDifference;
var lng = minLng + Math.random() * lngDifference;
var latLng = new google.maps.LatLng(lat, lng);
latLngArray.push(latLng);
}
for (var i = 0; i < latLngArray.length; i++) {
var marker = new google.maps.Marker({
position: latLngArray[i],
title: "Marker: " + i
});
markers.push(marker);
marker.setMap(map);
}
}
function UpdateZoomLabel() {
var displayZoomLabel = document.getElementById("display-zoom-label"),
// get current zoom
zoomValue = map.getZoom();
displayZoomLabel.innerHTML = "The Current Map's Zoom is: " + zoomValue;
}
// Initialize the map object
function initialize() {
var latlng = new google.maps.LatLng(-34.397, 150.644);
var mapOptions = {
zoom: 8,
center: latlng
};
map = new google.maps.Map(document.getElementById('map-container'), mapOptions);
firstBoundChangedListener = google.maps.event.addListener(map, "bounds_changed", function () {
if (firstBoundChangedListener) google.maps.event.removeListener(firstBoundChangedListener);
// call add markers: add 'n' markers randomly
addMarkers(6);
});
//Listen for the 'zoom_changed' event of the map
google.maps.event.addListener(map, "zoom_changed", function () {
//show zoom in label
UpdateZoomLabel();
});
UpdateZoomLabel();
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
</body>
</html>