我有这段代码来从谷歌地图上的数据库中填充标记，但它不起作用，xml文件完全起作用，我引用了https://developers.google.com/maps/articles/phpsqlajax_v3，但没有用。
markers.php代码
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "jainmunilocator";
$connection=mysqli_connect($servername, $username, $password, $dbname);;
if (!$connection) {
die("Connection failed: " . mysqli_connect_error());
}
$sql = "SELECT name,id,lat,lng FROM muni_location,munishri WHERE mid=id";
header('Content-Type: application/xml');
$result=mysqli_query($connection,$sql);
$dom = new DOMDocument("1.0");
$node = $dom->createElement("markers");
$parnode = $dom->appendChild($node);
if (mysqli_num_rows($result) > 0)
{
while($row = mysqli_fetch_assoc($result)){
if(isset($row['id'])){ $id = $row['id']; }
if(isset($row['name'])){ $name = $row['name']; }
if(isset($row['lat'])){ $lat = $row['lat']; }
if(isset($row['lng'])){ $lng = $row['lng']; }
$node = $dom->createElement("marker");
$newnode = $parnode->appendChild($node);
$newnode->setAttribute("id",$id);
$newnode->setAttribute("name", $name);
$newnode->setAttribute("lat", $lat);
$newnode->setAttribute("lng", $lng);
}
}
echo $dom->saveXML();
?>
*谷歌地图标记代码**
<!DOCTYPE html >
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<title>PHP/MySQL & Google Maps Example</title>
<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js"></script>
<script type="text/javascript">
//<![CDATA[
function load() {
var map = new google.maps.Map(document.getElementById("map"), {
center: new google.maps.LatLng(22.6145,77.3418),
zoom: 7,
mapTypeId: 'roadmap'
});
var infoWindow = new google.maps.InfoWindow;
var gm_marker = new Array();
// Change this depending on the name of your PHP file
downloadUrl("markers.php", function(data) {
var xml = data.responseXML;
var markers = xml.documentElement.getElementsByTagName("marker");
for (var i = 0; i < markers.length; i++) {
var id = markers[i].getAttribute("id");
var name = markers[i].getAttribute("name");
var point = new google.maps.LatLng(
parseFloat(markers[i].getAttribute("lat")),
parseFloat(markers[i].getAttribute("lng")));
//var html = "<b>" + name + "</b> <br/>" + id;
var html = name;
var icon = 'http://labs.google.com/ridefinder/images/mm_20_blue.png';
var marker = new google.maps.Marker({
map: map,
position: point,
title: name
});
addMarker(point,name);
bindInfoWindow(marker, map, infoWindow, html);
}
});
}
//stackoverflow
function addMarker(latLng, contentstr) {
var marker = new google.maps.Marker({
position: latLng,
map: map
});
google.maps.event.addListener(marker, 'click', function() {
infowindow = new google.maps.InfoWindow({
content: contentstr
});
});
gm_markers.push(marker);
}
setAllmap(map);
function setAllMap(map) {
for (var i = 0; i < gm_markers.length; i++) {
gm_markers[i].setMap(map);
}
function showMarkers() { setAllMap(map);}
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() {}
//]]>
</script>
</head>
<body onload="load()">
<div id="map-canvas-show" style="width: 100%; height: 300px;"></div>
</body>
</html>
我认为有两个元素是必不可少的，但在您的代码中没有看到。这是我的来源，我将它们包括在这里，以展示这些概念。您可以在for循环中实现这种类型的东西，也可以分解为多个函数。我更喜欢函数，所以我是这样做的。
首先，我要确认您的标记数组的长度不是0——这是一个简单的健全性检查——确保您有要加载的标记
构建谷歌地图标记堆栈
虽然有标记。。。
-
使用新创建标记
-
创建具有新的侦听器
-
将标记作为标记对象数组推入谷歌的标记对象
// Add a marker to the map and push to the array.
function addMarker(latLng, contentstr) {
var marker = new google.maps.Marker({
position: latLng,
map: map
});
google.maps.event.addListener(marker, 'click', function() {
infowindow = new google.maps.InfoWindow({
content: contentstr
});
});
gm_markers.push(marker);
}
要显示标记，请将标记指定给地图
将阵列中的每个标记与地图画布相关联。
// Sets the map on all markers in the array.
function setAllMap(map) {
for (var i = 0; i < gm_markers.length; i++) {
gm_markers[i].setMap(map);
}
清除谷歌地图标记（关闭）
强化这个概念。若要清除标记，请从地图对象中拔下地图标记对象阵列。
// Removes the markers from the map, but keeps them in the array.
function clearMarkers() {
setAllMap(null);
}
显示已加载的标记（打开）
// Shows any markers currently in the array.
function showMarkers() {
setAllMap(map);
}
在视图中
显示带有标记的地图
<div id="map-canvas-show" style="width: 100%; height: 300px;"></div>
调试步骤（已添加）
我建议首先确认有效坐标正在加载到php中的标记vars中。事实上，我会从一个单一标记的测试开始。放入调试语句以显示您的lat和lng。这是至关重要的。将php中的有效标记数据确认到js中。
然后，您需要确认这些标记在您的谷歌地图的可见范围内标记在那里，只是看不见吗？为了帮助你，我建议你把谷歌地图放大，这样你就可以在半个地球上看到一个标记。