I already posted the answer in Detect a new Android notification:
You need to register an AccessibilityService and make sure the user enables the service.
Example for a service:
public class InstantMessenger extends AccessibilityService {
@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
if (event.getEventType() == AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED) {
//Do something, eg getting packagename
final String packagename = String.valueOf(event.getPackageName());
}
}
@Override
protected void onServiceConnected() {
if (isInit) {
return;
}
AccessibilityServiceInfo info = new AccessibilityServiceInfo();
info.eventTypes = AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED;
info.feedbackType = AccessibilityServiceInfo.FEEDBACK_SPOKEN;
setServiceInfo(info);
isInit = true;
}
@Override
public void onInterrupt() {
isInit = false;
}
}