Question

我使用Google Maps API请求路线，之后路线会自动居中，因为我使用的选项是“preserveViewport：false”。现在我希望转移中心一点点。所以我通过以下代码尝试了它：

var overlay_1 = new google.maps.OverlayView();
overlay_1.draw = function () {};
overlay_1.setMap(map_1);

var point_1
point_1 = overlay_1.getProjection().fromLatLngToContainerPixel(map_1.getCenter());
point_1.x = point_1.x + 300;
map_1.setCenter(overlay_1.getProjection().fromContainerPixelToLatLng(point_1));

当我启动网页时，我收到以下错误：

未捕获的TypeError：无法读取属性'fromLatLngToContainerPixel' 未定义的

正如您在我的Printscreen中看到的那样，当我将它放入我的控制台时代码正常工作。

有没有人知道为什么我在加载网页时遇到错误？

Answer 1

在projection_changed方法返回有效结果之前，您必须等待覆盖重叠.getProjection事件。

相关问题：Why getProjection() is not working in V3

var overlay_1 = new google.maps.OverlayView();
overlay_1.draw = function() {};
overlay_1.setMap(map_1);

var point_1;
google.maps.event.addListener(overlay_1, 'projection_changed', function() {
  point_1 = overlay_1.getProjection().fromLatLngToContainerPixel(map_1.getCenter());
  point_1.x = point_1.x + 300;

  map_1.setCenter(overlay_1.getProjection().fromContainerPixelToLatLng(point_1));
});

proof of concept fiddle

代码段

＆＃13;

function initialize() {
  var map_1 = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  var overlay_1 = new google.maps.OverlayView();
  overlay_1.draw = function() {};
  overlay_1.setMap(map_1);

  var point_1;
  google.maps.event.addListener(overlay_1, 'projection_changed', function() {
    point_1 = overlay_1.getProjection().fromLatLngToContainerPixel(map_1.getCenter());
    point_1.x = point_1.x + 300;
    map_1.setCenter(overlay_1.getProjection().fromContainerPixelToLatLng(point_1));
  });
}
google.maps.event.addDomListener(window, "load", initialize);

＆＃13;

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

＆＃13;

<script src="https://maps.googleapis.com/maps/api/js"></script>
<div id="map_canvas"></div>

＆＃13;

谷歌地图的转移中心（错误：无法读取未定义的属性'fromLatLngToContainerPixel'）

1 个答案: