javascript - 谷歌地图 API v3，getBound()；不返回当前视口(viewport)的纬度/经度范围

Question

我需要将我的混搭页面代码从 google map api v2 升级到 v3。但是 getBound() 不适用于新代码!错误在哪里？提前谢谢你。

旧代码是:

   <script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key= (my key api)"
      type="text/javascript"></script>

    <script type="text/javascript">

    function updateStatus() {
      var div = document.getElementById('mapinfo');
      div.innerHTML = map.getBounds();

      document.forms[0].lat0.value = map.getBounds().getSouthWest().lat();
      document.forms[0].lon0.value = map.getBounds().getSouthWest().lng();
      document.forms[0].lat1.value = map.getBounds().getNorthEast().lat();
      document.forms[0].lon1.value = map.getBounds().getNorthEast().lng();

      get_pictures();

    }

    function onMapMove() {
      //map.setCenter(map.getCenter());
      updateStatus();
    }

    function onMapZoom(oldZoom, newZoom) {
      //map.setCenter(map.getCenter(),newZoom)
      updateStatus();
    }


    function load() {
      if (GBrowserIsCompatible()) {
        var map = new GMap2(document.getElementById("map"));
        window.map = map
        map.setCenter(new GLatLng(41.879786443521795,12.427597045898438), 6);
        map.addControl(new GSmallMapControl());
        map.addControl(new GMapTypeControl());
        window.kh = new GKeyboardHandler(map);

        GEvent.addListener(map,'moveend',onMapMove);
        GEvent.addListener(map,'zoomend',onMapZoom);
        updateStatus();
      }
    }

    </script>

新代码:

 <script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key= (my api key)"
      type="text/javascript"></script>

       <script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>

      <script type="text/javascript"
  src="https://maps.googleapis.com/maps/api/js?libraries=weather&sensor=true">
</script>

    <script type="text/javascript">

    function updateStatus() {
      var div = document.getElementById('mapinfo');
      div.innerHTML = map.getBounds();

      document.forms[0].lat0.value = map.getBounds().getSouthWest().lat();
      document.forms[0].lon0.value = map.getBounds().getSouthWest().lng();
      document.forms[0].lat1.value = map.getBounds().getNorthEast().lat();
      document.forms[0].lon1.value = map.getBounds().getNorthEast().lng();

      get_pictures();

    }

    function onMapMove() {
      //map.setCenter(map.getCenter());
      updateStatus();
    }

    function onMapZoom(oldZoom, newZoom) {
      //map.setCenter(map.getCenter(),newZoom)
      updateStatus();
    }

    function load() {
      if (GBrowserIsCompatible()) {

        var mapOptions = {
        zoom: 6,
        center: new google.maps.LatLng(41.879786443521795,12.427597045898438),
        mapTypeId: google.maps.MapTypeId.ROADMAP
        };

        var map = new google.maps.Map(document.getElementById("map_canvas"),
        mapOptions);

        var weatherLayer = new google.maps.weather.WeatherLayer({
        temperatureUnits: google.maps.weather.TemperatureUnit.CELSIUS
        });
        weatherLayer.setMap(map);

        var cloudLayer = new google.maps.weather.CloudLayer();
        cloudLayer.setMap(map);

        updateStatus();
      }
    }

    </script>

Answer 1

目前 map 只能在初始化内部访问，使其全局可访问:

window.map = new google.maps.Map(/*.....*/);

此外:getBounds() 无法在 map 加载完成之前返回结果( map 加载是异步的，因此您不能立即调用 updateStatus())。

您可能会观察到 tilesloaded-event:

google.maps.event.addListenerOnce(map,'tilesloaded',updateStatus);

但是看起来你还想观察缩放和平移，你可以一次观察:

google.maps.event.addListener(map,'bounds_changed',updateStatus);