LatLng界限显示自定义标记

时间：2011-08-18 18:37:09

标签： javascript google-maps-api-3

我使用下面的代码在mySQL数据库中显示给定位置内的标记。我正在尝试设置LatLng边界，这样我就可以看到每个给定位置的所有标记但是它不起作用，即地图没有显示可视地图中的所有标记，我也收到一个错误，说'findid未定义'。作为一个新的东西，我不确定这段代码的代码或定位是否错误。

我只是想知道是否有可能请有人看看这个，让我知道我哪里出错了。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>All Locations</title>
        <link rel="stylesheet" href="css/alllocationsstyle.css" type="text/css" media="all" />
        <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false&language=en"></script>
        <script type="text/javascript"> 
            var customIcons = {
            Artefact: {
            icon: 'http://labs.google.com/ridefinder/images/mm_20_red.png',
            shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
            },
            Coin: {
            icon: 'http://labs.google.com/ridefinder/images/mm_20_green.png',
            shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
            },
            Jewellery: {
            icon: 'http://labs.google.com/ridefinder/images/mm_20_yellow.png',
            shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
            }
            };

            function load() { 
            var map = new google.maps.Map(document.getElementById("map"), { 
            center: new google.maps.LatLng(54.312195845815246,-4.45948481875007), 
            zoom:14, 
            mapTypeId: 'satellite' 
            }); 

            // Change this depending on the name of your PHP file 
            downloadUrl("phpfile.php", function(data) { 
            var xml = data.responseXML; 
            var markers = xml.documentElement.getElementsByTagName("marker"); 
            for (var i = 0; i < markers.length; i++) { 
            var findid = markers[i].getAttribute("findid");
            var locationid = markers[i].getAttribute("locationid"); 
            var dateoftrip = markers[i].getAttribute("dateoftrip");
            var findcategory = markers[i].getAttribute("findcategory");
            var findname = markers[i].getAttribute("findname");
            var finddescription = markers[i].getAttribute("finddescription");
            var detectorname = markers[i].getAttribute("detectorname");
            var searchheadname = markers[i].getAttribute("searchheadname");
            var detectorsettings = markers[i].getAttribute("detectorsettings");
            var pasref = markers[i].getAttribute("pasref");
            var findimage= markers[i].getAttribute("findimage");
            var additionalcomments= markers[i].getAttribute("additionalcomments");
            var point = new google.maps.LatLng( 
            parseFloat(markers[i].getAttribute("findosgb36lat")), 
            parseFloat(markers[i].getAttribute("findosgb36lon")));
            var icon = customIcons[findcategory] || {}; 
            var marker = new google.maps.Marker({          
            map: map, 
            position: point,
            title: 'Click to view details',
            icon: icon.icon,
            shadow: icon.shadow
            }); 

            } 
            }); 
            } 

            // Creating a LatLngBounds object
            var bounds = new google.maps.LatLngBounds();
            // Looping through the places array
            for (var i = 0; i < findid.length; i += 1) {
            // Extending the bounds object with each LatLng
            bounds.extend(findid[i]);
            }
            // Adjusting the map to new bounding box
            map.fitBounds(bounds)

            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"></div>
            </body> 
            </html>

更新代码 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>All Locations</title>
        <link rel="stylesheet" href="css/alllocationsstyle.css" type="text/css" media="all" />
        <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false&language=en"></script>
        <script type="text/javascript"> 
            var customIcons = {
            Artefact: {
            icon: 'http://labs.google.com/ridefinder/images/mm_20_red.png',
            shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
            },
            Coin: {
            icon: 'http://labs.google.com/ridefinder/images/mm_20_green.png',
            shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
            },
            Jewellery: {
            icon: 'http://labs.google.com/ridefinder/images/mm_20_yellow.png',
            shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
            }
            };

            var markers;

            function load() { 
            var map = new google.maps.Map(document.getElementById("map"), { 
            center: new google.maps.LatLng(54.312195845815246,-4.45948481875007), 
            zoom:14, 
            mapTypeId: 'satellite' 
            }); 

            // Change this depending on the name of your PHP file 
            downloadUrl("phpfile.php", function(data) { 
            var xml = data.responseXML; 
            var markers = xml.documentElement.getElementsByTagName("marker"); 
            for (var i = 0; i < markers.length; i++) { 
            var findid = markers[i].getAttribute("findid");
            var locationid = markers[i].getAttribute("locationid"); 
            var dateoftrip = markers[i].getAttribute("dateoftrip");
            var findcategory = markers[i].getAttribute("findcategory");
            var findname = markers[i].getAttribute("findname");
            var finddescription = markers[i].getAttribute("finddescription");
            var detectorname = markers[i].getAttribute("detectorname");
            var searchheadname = markers[i].getAttribute("searchheadname");
            var detectorsettings = markers[i].getAttribute("detectorsettings");
            var pasref = markers[i].getAttribute("pasref");
            var findimage= markers[i].getAttribute("findimage");
            var additionalcomments= markers[i].getAttribute("additionalcomments");
            var point = new google.maps.LatLng( 
            parseFloat(markers[i].getAttribute("findosgb36lat")), 
            parseFloat(markers[i].getAttribute("findosgb36lon")));
            var icon = customIcons[findcategory] || {}; 
            var marker = new google.maps.Marker({          
            map: map, 
            position: point,
            title: 'Click to view details',
            icon: icon.icon,
            shadow: icon.shadow
            }); 
            } 
            }); 
               // Creating a LatLngBounds object
            var bounds = new google.maps.LatLngBounds();
            // Looping through the places array
            for (var i = 0; i < markers.length; i += 1) {
            // Extending the bounds object with each LatLng
            bounds.extend(markers[i]);
            }
            // Adjusting the map to new bounding box
            map.fitBounds(bounds)   
            } 
            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"></div>
            </body> 
            </html>

1 个答案:

答案 0 :(得分：1)

当它不存在时，您试图遍历findid数组。有两个原因导致它不存在：

  1. 它没有在您尝试循环的范围内声明
  2. 即使它是，直到之后 ajax请求（用于获取XML数据）完成后才会定义

    3. Ajax中的“A”代表“异步”，这意味着当您请求某些内容时，您的代码会立即继续，并且不会等待服务器响应请求。

    至于第一点，您传递给downloadUrl的函数循环遍历XML中的<marker>元素，并将大量数据导入 local 变量，但是它实际上并没有对大多数人做任何事情。由于它们是本地的，因此在功能完成后它们不存在。实际上，它们只是被覆盖了每个<marker>元素，但就是这样。

    所以，不要试图在函数外部（不存在它）中遍历findid，而是将循环中的代码放入函数中，这样它就可以实际访问你在那里创建的标记。 / p>

    修改

    这里只是重写了load函数，所以它应该可以工作（你仍然需要其余的代码）。我已删除所有局部变量，因为您不会将它们用于任何事情。最后，您正在构建一个来自纬度/经度的标记 - 您没有使用的所有其他数据。如果您需要它，请稍后添加。

    function load() { 
    var map = new google.maps.Map(document.getElementById("map"), { 
        center: new google.maps.LatLng(54.312195845815246,-4.45948481875007), 
        zoom:14, 
        mapTypeId: 'satellite' 
    });

    var bounds  = new google.maps.LatLngBounds();
    var markers = [];

    downloadUrl("phpfile.php", function(data) { 
        var xml = data.responseXML; 
        var markers = xml.documentElement.getElementsByTagName("marker");
        // loop through the markers in the xml file
        for (var i = 0; i < markers.length; i++) { 
            var point = new google.maps.LatLng( 
                parseFloat(markers[i].getAttribute("findosgb36lat")), 
                parseFloat(markers[i].getAttribute("findosgb36lon"))
            );
            var icon = customIcons[findcategory] || {}; 
            var marker = new google.maps.Marker({          
                map: map, 
                position: point,
                title: 'Click to view details',
                icon: icon.icon,
                shadow: icon.shadow
            });
            // LatLngBounds expects a LatLng object - not a marker object
            bounds.extend(point);
        }
        // fit the map after all the points and markers have been created - i.e. after the loop
        map.fitBounds(bounds);
    });
}
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