我有一组点,我想在嵌入式谷歌地图(API v3)上绘制。我希望边界容纳所有的点,除非缩放级别太低(即,缩小太多)。我的方法是这样的:
var bounds = new google.maps.LatLngBounds();
// extend bounds with each point
gmap.fitBounds(bounds);
gmap.setZoom( Math.max(6, gmap.getZoom()) );
这行不通。最后一行“gmap.setZoom()”如果在fitBounds之后直接调用,则不会改变地图的缩放级别。
有没有一种方法来获得缩放级别的边界而不应用到地图?还有其他解决方法吗?
为了配合另一个解决方案-我发现“监听bounds_changed事件,然后设置新的缩放”方法对我来说并不可靠。我认为我有时在地图已经完全初始化之前调用fitBounds,初始化导致一个bounds_changed事件,将使用侦听器,在fitBounds改变边界和缩放级别之前。我最终得到了这段代码,到目前为止似乎还可以工作:
// If there's only one marker, or if the markers are all super close together,
// `fitBounds` can zoom in too far. We want to limit the maximum zoom it can
// use.
//
// `fitBounds` is asynchronous, so we need to wait until the bounds have
// changed before we know what the new zoom is, using an event handler.
//
// Sometimes this handler gets triggered by a different event, before
// `fitBounds` takes effect; that particularly seems to happen if the map
// hasn't been fully initialized yet. So we don't immediately remove the
// listener; instead, we wait until the 'idle' event, and remove it then.
//
// But 'idle' might happen before 'bounds_changed', so we can't set up the
// removal handler immediately. Set it up in the first event handler.
var removeListener = null;
var listener = google.maps.event.addListener(map, 'bounds_changed', () => {
console.log(map.getZoom());
if (map.getZoom() > 15) {
map.setZoom(15);
}
if (!removeListener) {
removeListener = google.maps.event.addListenerOnce(map, 'idle', () => {
console.log('remove');
google.maps.event.removeListener(listener);
});
}
});
我有同样的问题,我能够解决它使用下面的代码。这个监听器(google.maps.addListenerOnce())事件只会在map.fitBounds()执行之后被触发一次。所以,没有必要
跟踪并手动删除侦听器,或者
等待地图空闲。
它最初设置适当的缩放级别,并允许用户放大和缩小超过初始缩放级别,因为事件侦听器已经过期。例如,如果只调用google.maps.addListener(),那么用户将永远无法放大超过指定的缩放级别(在本例中为4)。由于我们实现了google.maps.addListenerOnce(),用户将能够放大到他/她选择的任何级别。
map.fitBounds(bounds);
var zoom_level_for_one_marker = 4;
google.maps.event.addListenerOnce(map, 'bounds_changed', function(event){
if (this.getZoom() >= zoom_level_for_one_marker){
this.setZoom(zoom_level_for_one_marker)
}
});