@Override
    public boolean isValid() {
        for (GeoItem item : getItems()) {
            if (!item.isValid()) {
                return false;
            }
        }
        return true;
    }
Represents a group of drawable GeoItem such as a point, polyline, polygon or enclosed groups
main/src/main/java/cgeo/geocaching/models/geoitem/GeoGroup.java