How to get all visible markers on current zoom lev

问题:

Here are some points:

1. I have some markers on the map and records associated with it on the right panel besides the map. They are connected via numeric id, which is stored as a property of marker.
2. All the markers are stored in an array.
3. When the user zooms in the map, records, associated to only visible markers should be shown on the right panel.

So, how to get the list of all visible markers on the current zoom level? I've searched over the internet and didn't find something useful. Some kind of what I'm trying to achieve could be found here

回答1:

Use GMap2.getBounds() to find the bounding box. The use GLatLngBounds.containsLatLng() to check each marker to see if it is visible.

回答2:

In Google Maps JavaScript API V3 we can use something like this:

var markers; // your markers
var map; // your map
for (var i=0; i<markers.length; i++){
    if( map.getBounds().contains(markers[i].getPosition()) ){
        // code for showing your object, associated with markers[i]
    }
}

回答3:

I know you wanted API V2, but i had to correct some stuff i saw in @bruha's response for V3, in case someone comes looking for it:

var markers; // your markers
var map; // your map

for(var i = markers.length, bounds = map.getBounds(); i--;) {
    if( bounds.contains(markers[i].getPosition()) ){
        // code for showing your object
    }
}

going backwards through the array this way goes through the array of markers faster, plus we set the bounds into a variable before going into the loop so we're not requesting it every time we go through the loop, and the only request we have to make is if the specific marker lies inside the bounds.

EDIT: goofed my decrementer

EDIT: map.getBounds() should be, was map.getBounds

回答4:

It's easy code. Try this code.

private boolean CheckVisibility(Marker marker)
{
    if(googleMap != null)
    {
        //This is the current user-viewable region of the map
        LatLngBounds latLongBounds = googleMap.getProjection().getVisibleRegion().latLngBounds;

            if(latLongBounds.contains(marker.getPosition()))
                   //If the item is within the the bounds of the screen
                  return true;
            else
                  //If the marker is off screen
                  return false;
    }
    return false;
}

回答5:

My code snippet

private boolean isAnyMarkerVisible(LatLng ll) {
    if(gMap != null && markersData != null) {
        final LatLngBounds latLongBounds = LatLngBounds.builder().include(ll).build();
        for (Store store : markersData) {
            if (latLongBounds.contains(store.getLatLng())) {
                return true;
            }
        }
    }
    return false;
}