将谷歌地图放在数据库的中心？

Question

我正在尝试将谷歌地图集中在从数据库中提取的单个标记上，到目前为止我所做的是使用此函数从数据库中获取单个标记

function getMarkers(){
        var urlstr="readsingle.php?v=<?php echo $cam ?>";
        var request = GXmlHttp.create();
        request.open('GET', urlstr , true); // request XML from PHP with AJAX call
        request.onreadystatechange = function () {
            if (request.readyState == 4) { // 4 is a completed request
                var xmlDoc = request.responseXML;
                locations = xmlDoc.documentElement.getElementsByTagName("location");
                markers = [];
                if (locations.length){
                    for (var i = 0; i < locations.length; i++) { // cycle thru locations
                        markers[i] = new GMarker(new GLatLng(locations[i].getAttribute("lat"),locations[i].getAttribute("lng")));
                        markers[i].infowindow = "This is "+locations[i].getAttribute("name");
                        markers[i].markerindex = i;
                        markers[i].db_id = locations[i].getAttribute("location_id");
                        map.addOverlay(markers[i]);

                    }
                }
            }
        }

        request.send(null);

    }

还有这个函数来加载地图

    function onLoad() {
      map = new GMap(document.getElementById("div_map"));
      map.addControl(new GSmallMapControl());
      map.addControl(new GMapTypeControl());
      map.setCenter(new GLatLng(53.76221, -2.71227), 8);
      map.enableScrollWheelZoom();
      getMarkers();
      GEvent.addListener(map, "click", function(overlay, point) {
          if (overlay){ // marker clicked
              overlay.openInfoWindowHtml(overlay.infowindow);   // open InfoWindow
          } else if (point) {   // background clicked

          }
      });
    }

如何更改此行的 Lat Lng 值

map.setCenter(new GLatLng(53.76, -2.71), 5); 

匹配来自单个标记的 lat lng 值？还是有更简单的方法从数据库中提取单个标记并将地图居中放置？

Answer 1

如果getMarkers() 只检索一个标记，看起来您可以简单地添加：

map.setCenter(new GLatLng(locations[i].getAttribute("lat"), 
                          locations[i].getAttribute("lng")), 5);

在将标记添加到地图之后或之前：

map.addOverlay(markers[i]);