试图从外部PHP文件标记数据创建Google Maps api群集

Question

我正在尝试从数据库中的位置显示标记并将它们聚类。我可以正常显示标记，但似乎无法弄清楚如何为群集创建纬度和经度数组。我从这样的外部php文件中获取数据-

function initMap() {
     var map = new google.maps.Map(document.getElementById('grid-map'), {
         var infoWindow = new google.maps.InfoWindow;

         downloadUrl('myfile.php', function(data) {
         var xml = data.responseXML;
         var markers = xml.documentElement.getElementsByTagName('marker');
         Array.prototype.forEach.call(markers, function(markerElem) {

         // Returned marker data from php file //
          var id = markerElem.getAttribute('id');
          var name = markerElem.getAttribute('title');
          var city = markerElem.getAttribute('city');

          // Lat and Long for each marker
          var point = new google.maps.LatLng(
            parseFloat(markerElem.getAttribute('lat')),
            parseFloat(markerElem.getAttribute('lng'))
          );

          var marker;
            var iconBase = 'mysite.com/img/';           
            marker = new google.maps.Marker({
                map: map,
                position: point,         
                title: name,
                icon: iconBase + 'loc.png'
            });   

           marker.addListener('click', function() {
               map.setZoom(14);
               map.setCenter(marker.getPosition());
           });

           marker.addListener('click', function() {
               infoWindow.setContent(infowincontent);
               infoWindow.open(map, marker);
               return 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() {}

<script src="https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/markerclusterer.js"></script>

这里是集群呼叫-

 // Add a marker cluster to manage the markers.
    var markerCluster = new MarkerClusterer(map, markers,
        {imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m',zoomOnClick: false});

这是myfile.php中的循环

$sql = "SELECT * FROM `table`";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        $id = $row['id'];
        $lat = $row['lat'];
        $lng = $row['lng'];
        $title =$row['post_title'];
        $city = $row['post_city'];
        $price = $row['post_price'];

        echo "<marker id='".$id."' price='".$price."' title='".$title."' city='".$city."'  lat='".$lat."' lng='".$lng."' type='X'/>";
   }
}

我只是从文件中复制了相关代码，试图使其保持可读性，所以我可能缺少括号。基本上，我认为我需要为群集创建一个坐标数组，或者是否可以对已经显示的位置进行群集？

Answer 1

现有代码的最简单方法是在创建标记之前定义MarkerClusterer，然后在创建它们时将每个标记添加到其中。>

1. 在加载XML之前，使用空数组创建MarkerClusterer：