How can i access all marker on my GoogleMap-Object

问题:

i am currently trying to implement an ActionBar-Button that on usage sets all my markers on my GoogleMap-object visible or invisible. My problem is that i don't know how i can get a reference to all my markers once they have been created and are shown on my map. Im looking for a solution where i stash all my marker-objects into an array, that i can access in other parts of my code aswell. is this approach reasonable?

here is what i am thinking of:

 private Marker[] mMarkerArray = null;
 for (int i = 0; i < MainActivity.customers.size(); i++) {

     LatLng location = new LatLng(mData.lat, mData.lng);

     Marker marker = mMap.addMarker(new MarkerOptions().position(location)
                          .title(mData.title)
                          .snippet(mData.snippet));
     mMarkerArray.add(marker);                      
   }

and set all my markers invisible on within another method:

for (int i = 0;  i < mMarkerArray.length;; i++) {
    mMarkerArray[i].setVisible(false);
}

it refuses to add the markers to a Marker[]-array. how can i achieve it?

mMarkerArray.add(marker) doesnt work

回答1:

i figured out an answer that also regards my customerList having customers without coordinates --> (0,0;0,0). inspired by this blog.

initialize ArrayList:

private ArrayList<Marker> mMarkerArray = new ArrayList<Marker>();

add marker to my map and to the mMarkerArray:

for (int i = 0; i < MainActivity.customers.size(); i++) {
        Customer customer = MainActivity.customers.get(i);
        if (customer.getLon() != 0.0) {
            if (!customer.isProspect()) {
                Data mData= new Data(customer.getLat(),customer.getLon(),customer.getName(),
                        customer.getOrt());

                LatLng location = new LatLng(mData.lat, mData.lng);

                Marker marker = mMap.addMarker(new MarkerOptions().position(location)
                          .title(mData.title)
                          .snippet(mData.snippet));

                mMarkerArray.add(marker); 
}}} 

set all markers not-visible

for (Marker marker : mMarkerArray) {
    marker.setVisible(false);
    //marker.remove(); <-- works too!
}

回答2:

You can keep a Collection of OverlayItem within your Activity or Fragment and then call MapView.getOverlays().clear() to make them "invisible" and then add them back to make them visible again. Call MapView.invalidate() after each action to cause the map to be repainted.

回答3:

Replace

private Marker[] mMarkerArray = null;

with

private List<Marker> mMarkerArray = new ArrayList<Marker>();

and you should be fine.

If you use Android Maps Extensions, you can simply iterate over all markers using

for (Marker marker : googleMap.getMarkers()) {
    marker.setVisible(false);
}

without having your own List of all Markers.