Question

我有一个问题，当我在我的服务器的自定义地图中使用此代码时（下面是google文档中的示例，但我的脚本类似，不包括地图的路径）。异步加载对我不起作用：

<!DOCTYPE html>
<html>
  <head>
    <title>Image map types</title>
    <style>
      html, body, #map-canvas {
        height: 100%;
        margin: 0px;
        padding: 0px
      }
    </style>
    <script>
var moonTypeOptions = {
  getTileUrl: function(coord, zoom) {
      var normalizedCoord = getNormalizedCoord(coord, zoom);
      if (!normalizedCoord) {
        return null;
      }
      var bound = Math.pow(2, zoom);
      return 'http://mw1.google.com/mw-planetary/lunar/lunarmaps_v1/clem_bw' +
          '/' + zoom + '/' + normalizedCoord.x + '/' +
          (bound - normalizedCoord.y - 1) + '.jpg';
  },
  tileSize: new google.maps.Size(256, 256),
  maxZoom: 9,
  minZoom: 0,
  radius: 1738000,
  name: 'Moon'
};

var moonMapType = new google.maps.ImageMapType(moonTypeOptions);

function initialize() {
  var myLatlng = new google.maps.LatLng(0, 0);
  var mapOptions = {
    center: myLatlng,
    zoom: 1,
    streetViewControl: false,
    mapTypeControlOptions: {
      mapTypeIds: ['moon']
    }
  };

  var map = new google.maps.Map(document.getElementById('map-canvas'),
      mapOptions);
  map.mapTypes.set('moon', moonMapType);
  map.setMapTypeId('moon');
}

// Normalizes the coords that tiles repeat across the x axis (horizontally)
// like the standard Google map tiles.
function getNormalizedCoord(coord, zoom) {
  var y = coord.y;
  var x = coord.x;

  // tile range in one direction range is dependent on zoom level
  // 0 = 1 tile, 1 = 2 tiles, 2 = 4 tiles, 3 = 8 tiles, etc
  var tileRange = 1 << zoom;

  // don't repeat across y-axis (vertically)
  if (y < 0 || y >= tileRange) {
    return null;
  }

  // repeat across x-axis
  if (x < 0 || x >= tileRange) {
    x = (x % tileRange + tileRange) % tileRange;
  }

  return {
    x: x,
    y: y
  };
}

google.maps.event.addDomListener(window, 'load', initialize);

function loadScript() {
  var script = document.createElement('script');
  script.type = 'text/javascript';
  script.src = 'http://maps.googleapis.com/maps/api/js?sensor=false&' +
      'callback=initialize';
  document.body.appendChild(script);
}

window.onload = loadScript;

      </script>
  </head>
  <body>
    <div id="map-canvas"></div>
  </body>
</html>

我的网站空白，控制台告诉我：

Uncaught ReferenceError: google is not defined

但是当我使用这段代码时：

<!DOCTYPE html>
<html>
  <head>
    <title>Image map types</title>
    <style>
      html, body, #map-canvas {
        height: 100%;
        margin: 0px;
        padding: 0px
      }
    </style>
    <script>
function loadScript() {
  var script = document.createElement('script');
  script.type = 'text/javascript';
  script.src = 'http://maps.googleapis.com/maps/api/js?sensor=false&' +
      'callback=initialize';
  document.body.appendChild(script);
}

window.onload = loadScript; 

var moonTypeOptions = {
  getTileUrl: function(coord, zoom) {
      var normalizedCoord = getNormalizedCoord(coord, zoom);
      if (!normalizedCoord) {
        return null;
      }
      var bound = Math.pow(2, zoom);
      return 'http://mw1.google.com/mw-planetary/lunar/lunarmaps_v1/clem_bw' +
          '/' + zoom + '/' + normalizedCoord.x + '/' +
          (bound - normalizedCoord.y - 1) + '.jpg';
  },
  tileSize: new google.maps.Size(256, 256),
  maxZoom: 9,
  minZoom: 0,
  radius: 1738000,
  name: 'Moon'
};

var moonMapType = new google.maps.ImageMapType(moonTypeOptions);

function initialize() {
  var myLatlng = new google.maps.LatLng(0, 0);
  var mapOptions = {
    center: myLatlng,
    zoom: 1,
    streetViewControl: false,
    mapTypeControlOptions: {
      mapTypeIds: ['moon']
    }
  };

  var map = new google.maps.Map(document.getElementById('map-canvas'),
      mapOptions);
  map.mapTypes.set('moon', moonMapType);
  map.setMapTypeId('moon');
}

// Normalizes the coords that tiles repeat across the x axis (horizontally)
// like the standard Google map tiles.
function getNormalizedCoord(coord, zoom) {
  var y = coord.y;
  var x = coord.x;

  // tile range in one direction range is dependent on zoom level
  // 0 = 1 tile, 1 = 2 tiles, 2 = 4 tiles, 3 = 8 tiles, etc
  var tileRange = 1 << zoom;

  // don't repeat across y-axis (vertically)
  if (y < 0 || y >= tileRange) {
    return null;
  }

  // repeat across x-axis
  if (x < 0 || x >= tileRange) {
    x = (x % tileRange + tileRange) % tileRange;
  }

  return {
    x: x,
    y: y
  };
}

google.maps.event.addDomListener(window, 'load', initialize);

      </script>
  </head>
  <body>
    <div id="map-canvas"></div>
  </body>
</html>

Google地图已加载到页面上，但仍会显示：

Uncaught ReferenceError: google is not defined

可能是什么原因？

Answer 1

在全局范围内（函数外）发生google会导致此错误。您第一次访问google时会访问initialize。

自定义谷歌地图中的异步不起作用

1 个答案: