/** Notifies the listener about possible region-based events */
private void notifyListener() {
IBeacon newNearestBeacon = null;
if (_arrOrderedIBeacons.size() > 0) newNearestBeacon = _arrOrderedIBeacons.get(0);
// Case 1: enter iBeacon region from nowhere
if (_previousNearestIBeacon == null && newNearestBeacon != null) {
_listener.enterRegion(newNearestBeacon);
_previousNearestIBeacon = newNearestBeacon;
}
// Case 2: keep in the same iBeacon region, update proximity
else if (_previousNearestIBeacon != null
&& newNearestBeacon != null
&& _previousNearestIBeacon.equals(newNearestBeacon)) {
_previousNearestIBeacon = newNearestBeacon;
}
// Case 3: enter a different iBeacon region (roaming)
else if (_previousNearestIBeacon != null
&& newNearestBeacon != null
&& !_previousNearestIBeacon.equals(newNearestBeacon)) {
_listener.exitRegion(_previousNearestIBeacon);
_listener.enterRegion(newNearestBeacon);
_previousNearestIBeacon = newNearestBeacon;
}
// Case 4: leave iBeacon region
else if (_previousNearestIBeacon != null && newNearestBeacon == null) {
_listener.exitRegion(_previousNearestIBeacon);
_previousNearestIBeacon = null;
}
}
