我从这篇关于 SO如何安全地为谷歌地图加载外部 JSON 样式文件并通过使用回调函数避免竞争条件的帖子中了解到。但是,添加该代码似乎破坏了地图上所有在添加该代码之前曾经可以工作的后续操作。
这是一个演示该问题的片段(注释掉 javascript 的第 6-39 行,取消注释第 41-49 行演示了除样式之外的所有其他工作)。
添加基于回调的 JSON 地图样式是如何破坏所有后续操作的?
var map;
var myParser;
var markerClusterer;
function initMap() {
function loadJSON(callback) {
var xobj = new XMLHttpRequest();
xobj.overrideMimeType("application/json");
xobj.open('GET', 'https://api.myjson.com/bins/uvef2', true);
const readyOK = 4;
const responseOK = 200;
xobj.onreadystatechange = function() {
if (xobj.readyState === readyOK && xobj.status === responseOK) {
callback(xobj.responseText);
}
};
xobj.send(null);
}
var loaded_json;
loadJSON(function(response) {
loaded_json = JSON.parse(response);
// console.log("loaded json");
// console.log(loaded_json);
var styledMapType = new google.maps.StyledMapType(loaded_json, {
name: 'Map'
});
map = new google.maps.Map(document.getElementById('map'), {
gestureHandling: 'greedy',
center: {lat: 45.41, lng: -75.7},
zoom: 14,
mapTypeControlOptions: {
mapTypeIds: ['roadmap', 'satellite', 'hybrid', 'terrain', 'styled_map']
}
});
// console.log("loaded map");
map.mapTypes.set('styled_map', styledMapType);
map.setMapTypeId('styled_map');
console.log("styled_map set");
});
/* map = new google.maps.Map(document.getElementById('map'), {
gestureHandling: 'greedy',
center: {lat: 45.41, lng: -75.7},
zoom: 14,
mapTypeControlOptions: {
mapTypeIds: ['roadmap', 'satellite', 'hybrid', 'terrain', 'styled_map']
}
});
*/
markerClusterer = new MarkerClusterer(map, [], {});
myParser = new geoXML3.parser({
map: map,
zoom: false,
markerOptions: {
icon: {
url: "http://maps.google.com/mapfiles/ms/icons/yellow-dot.png", // url
scaledSize: new google.maps.Size(32, 32) // scaled size
}
},
createMarker: function(placemark) {
var marker = myParser.createMarker(placemark);
markerClusterer.addMarker(marker);
return marker;
},
afterParse: useData
});
myParser.parseKmlString(file2kml);
function useData(docs) {
console.log("parsed " + docs[0].placemarks.length + " placemarks");
}
}
google.maps.event.addDomListener(window, 'load', initMap);
var file2kml = `<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document>
<name>test placemarks</name>
<Style id="icon-1899-DB4436-labelson">
<IconStyle>
<color>ff3644db</color>
<scale>1</scale>
<Icon>
<href>http://maps.google.com/mapfiles/ms/icons/red-dot.png</href>
</Icon>
<hotSpot x="32" xunits="pixels" y="64" yunits="insetPixels"/>
</IconStyle>
</Style>
<Placemark>
<name>Church Of Ascension</name>
<description><![CDATA[latitude: 45.410755<br>longitude: -75.681623]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.410755</value>
</Data>
<Data name="longitude">
<value>-75.681623</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.681623,45.410755,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Bank Street Dragon</name>
<description><![CDATA[latitude: 45.420032<br>longitude: -75.699788]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.420032</value>
</Data>
<Data name="longitude">
<value>-75.699788</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.699788,45.420032,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Place Bell Canada</name>
<description><![CDATA[latitude: 45.420214<br>longitude: -75.692603]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.420214</value>
</Data>
<Data name="longitude">
<value>-75.692603</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.692603,45.420214,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>The Royal Canadian Legion Dominion Command</name>
<description><![CDATA[latitude: 45.310682<br>longitude: -75.899762]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.310682</value>
</Data>
<Data name="longitude">
<value>-75.899762</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.899762,45.310682,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Lieutenant Colonel John By</name>
<description><![CDATA[latitude: 45.422076<br>longitude: -75.692515]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.422076</value>
</Data>
<Data name="longitude">
<value>-75.692515</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.692515,45.422076,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Oscar Peterson, the Street Musician</name>
<description><![CDATA[latitude: 45.42268<br>longitude: -75.693955]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.42268</value>
</Data>
<Data name="longitude">
<value>-75.693955</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.693955,45.42268,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Somerset Square</name>
<description><![CDATA[latitude: 45.406222<br>longitude: -75.722117]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.406222</value>
</Data>
<Data name="longitude">
<value>-75.722117</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.722117,45.406222,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Windsor Park Flood Control</name>
<description><![CDATA[latitude: 45.39149<br>longitude: -75.677548]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.39149</value>
</Data>
<Data name="longitude">
<value>-75.677548</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.677548,45.39149,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Frank Clair Statue</name>
<description><![CDATA[latitude: 45.397413<br>longitude: -75.683657]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.397413</value>
</Data>
<Data name="longitude">
<value>-75.683657</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.683657,45.397413,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Ottawa Mill St. Brewpub</name>
<description><![CDATA[latitude: 45.419537<br>longitude: -75.71263]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.419537</value>
</Data>
<Data name="longitude">
<value>-75.71263</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.71263,45.419537,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>David Perry Memorial Bench</name>
<description><![CDATA[latitude: 45.397002<br>longitude: -75.6743]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.397002</value>
</Data>
<Data name="longitude">
<value>-75.6743</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.6743,45.397002,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Companions of the Cross</name>
<description><![CDATA[latitude: 45.412132<br>longitude: -75.70911]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.412132</value>
</Data>
<Data name="longitude">
<value>-75.70911</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.70911,45.412132,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>The Sunburst Building</name>
<description><![CDATA[latitude: 45.419296<br>longitude: -75.699572]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.419296</value>
</Data>
<Data name="longitude">
<value>-75.699572</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.699572,45.419296,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Rideau Curling Club</name>
<description><![CDATA[latitude: 45.413011<br>longitude: -75.704687]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.413011</value>
</Data>
<Data name="longitude">
<value>-75.704687</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.704687,45.413011,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Carling Otrain Station </name>
<description><![CDATA[latitude: 45.397474<br>longitude: -75.709528]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.397474</value>
</Data>
<Data name="longitude">
<value>-75.709528</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.709528,45.397474,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Geese Artwork</name>
<description><![CDATA[latitude: 45.417308<br>longitude: -75.700673]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.417308</value>
</Data>
<Data name="longitude">
<value>-75.700673</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.700673,45.417308,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name><![CDATA[Saint Patrick\'s Basilica]]></name>
<description><![CDATA[latitude: 45.41667<br>longitude: -75.70057]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.41667</value>
</Data>
<Data name="longitude">
<value>-75.70057</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.70057,45.41667,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Headless Elephants</name>
<description><![CDATA[latitude: 45.409045<br>longitude: -75.688275]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.409045</value>
</Data>
<Data name="longitude">
<value>-75.688275</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.688275,45.409045,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Valour Bridge</name>
<description><![CDATA[latitude: 45.310651<br>longitude: -75.901318]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.310651</value>
</Data>
<Data name="longitude">
<value>-75.901318</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.901318,45.310651,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Marble Soccer Balls</name>
<description><![CDATA[latitude: 45.404574<br>longitude: -75.711718]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.404574</value>
</Data>
<Data name="longitude">
<value>-75.711718</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.711718,45.404574,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Shrine To Mary.</name>
<description><![CDATA[latitude: 45.414046<br>longitude: -75.708891]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.414046</value>
</Data>
<Data name="longitude">
<value>-75.708891</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.708891,45.414046,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Guigues Hall Saint Paul University</name>
<description><![CDATA[latitude: 45.408308<br>longitude: -75.676281]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.408308</value>
</Data>
<Data name="longitude">
<value>-75.676281</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.676281,45.408308,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Ottawa Chinese Bible Church</name>
<description><![CDATA[latitude: 45.41234<br>longitude: -75.680081]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.41234</value>
</Data>
<Data name="longitude">
<value>-75.680081</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.680081,45.41234,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Canadian Bank Note Company</name>
<description><![CDATA[latitude: 45.395734<br>longitude: -75.745783]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.395734</value>
</Data>
<Data name="longitude">
<value>-75.745783</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.745783,45.395734,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>Dominion Arboretum</name>
<description><![CDATA[latitude: 45.391174<br>longitude: -75.704042]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.391174</value>
</Data>
<Data name="longitude">
<value>-75.704042</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.704042,45.391174,0
</coordinates>
</Point>
</Placemark>
<Placemark>
<name>BiTe This</name>
<description><![CDATA[latitude: 45.395077<br>longitude: -75.747579]]></description>
<styleUrl>#icon-1899-DB4436-labelson</styleUrl>
<ExtendedData>
<Data name="latitude">
<value>45.395077</value>
</Data>
<Data name="longitude">
<value>-75.747579</value>
</Data>
</ExtendedData>
<Point>
<coordinates>
-75.747579,45.395077,0
</coordinates>
</Point>
</Placemark>
</Document>
</kml>
`;
html,
body {
height: 100%;
;
width: 100%;
padding: 0px;
margin: 0px;
}
#map {
height: 90%;
width: 100%;
}
<script src="https://maps.googleapis.com/maps/api/js"></script>
<script src="https://cdn.rawgit.com/geocodezip/geoxml3/master/polys/geoxml3.js"></script>
<script src="https://cdn.rawgit.com/googlemaps/v3-utility-library/master/markerclustererplus/src/markerclusterer.js"></script>
<div id="map"></div>