我正在尝试从 JSON 文件创建路径，但无法显示该路径。控制台中没有任何错误或指示说明原因。除了 getJSON 循环之外，此代码直接来自 Google Example 。当我尝试将新的坐标对插入数组时，出现了问题。
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no">
<meta charset="utf-8">
<title>Simple Polylines</title>
<style>
html, body, #map-canvas {
height: 100%;
margin: 0px;
padding: 0px
}
</style>
<script src="http://code.jquery.com/jquery-2.1.0.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?v=3.exp"></script>
<script>
function initialize() {
var mapOptions = {
zoom: 3,
center: new google.maps.LatLng(0, -180),
mapTypeId: google.maps.MapTypeId.TERRAIN
};
var map = new google.maps.Map(document.getElementById('map-canvas'),
mapOptions);
var routeCoordinates = [];
$.getJSON('Tour_Down_Under_Stage_One.json', function(data) {
for (var i in data.points) {
coordinates = new google.maps.LatLng(data.points[i].latitude, data.points[i].longitude)
routeCoordinates.push(coordinates);
}
});
var route = new google.maps.Polyline({
path: routeCoordinates,
geodesic: true,
strokeColor: '#FF0000',
strokeOpacity: 1.0,
strokeWeight: 2
});
route.setMap(map);
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
</head>
<body>
<div id="map-canvas"></div>
</body>
</html>
这就是文件的样子。我知道它解析正确，因为我可以很好地 console.log 数据。这是与构建数组有关的事情。
{
"points": [
{
"distance": 0.0,
"latitude": -34.964927695699998,
"longitude": 138.647018457,
"elevation": 169.94999999999999
},
{
"distance": 0.0,
"latitude": -34.964927695699998,
"longitude": 138.647018457,
"elevation": 169.94999999999999
},
{
"distance": 8.1500000000000004,
"latitude": -34.964965833400001,
"longitude": 138.647094732,
"elevation": 170.0
},
{
"distance": 17.93,
"latitude": -34.965011598499999,
"longitude": 138.64718626300001,
"elevation": 170.06999999999999
},
{
"distance": 27.079999999999998,
"latitude": -34.965064991299997,
"longitude": 138.64726253800001,
"elevation": 170.36000000000001
},
{
"distance": 52.659999999999997,
"latitude": -34.965213769999998,
"longitude": 138.64747619299999,
"elevation": 171.03999999999999
},
{
"distance": 63.43,
"latitude": -34.965274790300001,
"longitude": 138.64756772300001,
"elevation": 172.0
},
{
"distance": 73.459999999999994,
"latitude": -34.965339666200002,
"longitude": 138.647644082,
"elevation": 172.97
},
{
"distance": 84.780000000000001,
"latitude": -34.965408314000001,
"longitude": 138.64773561199999,
"elevation": 173.96000000000001
},
// LOTS MORE OF THESE //
],
"totalDistance": 138442.46999999991,
"routeName": "Tour_Down_Under_Stage_One"
}
最佳答案
$.getJSON() 是一个异步函数。它获取的 JSON 数据在函数返回后不可用，而您的代码尝试使用它。相反，您需要将此代码移动到 $.getJSON() 回调内部，或者移动到该回调调用的函数中。
此外，您不应使用 for..in 循环来循环数组。使用老式的数字 for 循环，或者 .forEach() 等。
因此，代码的固定(但未经测试)版本可能如下所示:
function initialize() {
var mapOptions = {
zoom: 3,
center: new google.maps.LatLng(0, -180),
mapTypeId: google.maps.MapTypeId.TERRAIN
};
var map = new google.maps.Map(document.getElementById('map-canvas'),
mapOptions);
$.getJSON('Tour_Down_Under_Stage_One.json', function(data) {
var routeCoordinates = [];
data.points.forEach( function( point ) {
var coordinates =
new google.maps.LatLng( point.latitude, point.longitude );
routeCoordinates.push(coordinates);
});
var route = new google.maps.Polyline({
path: routeCoordinates,
geodesic: true,
strokeColor: '#FF0000',
strokeOpacity: 1.0,
strokeWeight: 2
});
route.setMap(map);
});
}
google.maps.event.addDomListener(window, 'load', initialize);
关于javascript - Google API 路径未显示，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27339769/