Questions about android-beacon-library's scan-period - ibeacon

Question

I have a problem about scan-period when i'm using android-beacon-library. And here is my problem:
I have three main class: MainActivity, BaseService and BeaconService.
MainActivity: Just do startForeground and stopForeground operation.
BaseService: Do some parameters initialization, BeaconManager and so on.
BeaconService: Beacon operation.
I describe my problems first. I’m using a foreground service to do scan operation and the backgroundScanPeriod is 20l. And i also have a MainActivity with two buttons, startService and stopService. The scan-period is 10s when First time i open the app and click startService.
And then i click HOME and kill this app the service is running normal and the scan-period is 10s also. But when i re-open MainActivity by click the notification on the picture.
The scan-period will become 1s. It's fast for me. But the scan-period would become normal if i click HOME again. That means, the scan-period will become very fast every time except the first time i open the MainActivity.
I wanna know why. And here is my important code below:
MainActivity.class
#OnClick(R.id.start_service)
void start_Service() {
if (Utils.isServiceRunning(MainActivity.this, Constants.CLASSNAME)) {
Toast.makeText(this, "service is running, don't start again", Toast.LENGTH_SHORT).show();
} else {
Intent intent = new Intent(MainActivity.this, BeaconService.class);
intent.setAction(Constants.ACTION.STARTFOREGROUND_ACTION);
startService(intent);
setInfo();
}
}
#OnClick(R.id.stop_service)
void stop_Service() {
if (Utils.isServiceRunning(MainActivity.this, Constants.CLASSNAME)) {
Intent intent = new Intent(MainActivity.this, BeaconService.class);
intent.setAction(Constants.ACTION.STOPFOREGROUND_ACTION);
startService(intent);
setInfo();
} else {
Toast.makeText(this, "service is dead, don't kill again", Toast.LENGTH_SHORT).show();
}
}
BaseService.class
private void setBeaconManager() {
beaconManager.setBackgroundBetweenScanPeriod(20l);
beaconManager.setBackgroundMode(true);
beaconManager.getBeaconParsers().clear();
beaconManager.getBeaconParsers().add(new BeaconParser().setBeaconLayout(Constants.BEACON_LAYOUT.COMMON_LAYOUT));
}
BeaconService.class
public class BeaconService extends BaseService implements BootstrapNotifier, BeaconConsumer {
private static final int NOTIFICATION = R.string.notify_service_started;
private static final String TAG = "BeaconService";
private int size = -1;
private RegionBootstrap regionBootstrap;
private BackgroundPowerSaver backgroundPowerSaver;
private Beacon beacon;
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
Log.d(TAG, "onCreate");
regionBootstrap = new RegionBootstrap(this, region);
beaconManager.bind(this);
backgroundPowerSaver = new BackgroundPowerSaver(getApplicationContext());
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
if (intent != null && intent.getAction() != null) {
switch (intent.getAction()) {
case Constants.ACTION.STARTFOREGROUND_ACTION:
startForeground(NOTIFICATION, getNotification());
break;
case Constants.ACTION.STOPFOREGROUND_ACTION:
Log.d(TAG, "Received stop foreground request");
stopForeground(true);
stopSelf();
break;
}
}
return START_STICKY;
}
#Override
public void onDestroy() {
beaconManager.unbind(this);
regionBootstrap.disable();
Log.d(TAG, "service onDestroy");
}
/**
* Called when at least one beacon in a Region is visible.
*
* #param region region
*/
#Override
public void didEnterRegion(Region region) {
// TODO: 3/8/16 reload all the resource
Log.d(TAG, "didEnterRegion called");
L.object(region);
try {
beaconManager.startRangingBeaconsInRegion(region);
} catch (RemoteException e) {
e.printStackTrace();
}
}
/**
* Called when no beacons in a Region are visible.
*
* #param region region
*/
#Override
public void didExitRegion(Region region) {
// TODO: 3/8/16 close all the resource
Log.d(TAG, "didExitRegion called");
try {
beaconManager.stopRangingBeaconsInRegion(region);
} catch (RemoteException e) {
e.printStackTrace();
}
beaconManager.unbind(this);
regionBootstrap.disable();
L.object(region);
}
/**
* Called with a state value of MonitorNotifier.INSIDE when at least one beacon in a Region is visible
*
* #param region region
*/
#Override
public void didDetermineStateForRegion(int i, Region region) {
Log.d(TAG, "switch from seeing/not seeing beacons");
L.object(region);
}
#Override
public void onBeaconServiceConnect() {
Log.d(TAG, "onBeaconServiceConnect");
if (null == beaconManager.getRangingNotifier()) {
beaconManager.setRangeNotifier(new RangeNotifier() {
#Override
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
Log.d(TAG, "beacons.size():" + beacons.size() + "," + this);
if (beacons.size() != 0) {
Iterator<Beacon> iterator = beacons.iterator();
if (beacons.size() != size) {
saveBeacon(iterator);
size = beacons.size();
}
}
}
});
}
}
/**
* Save beacon p-o-j-o to SQLite.
*/
private void saveBeacon(Iterator<Beacon> iterator) {
while (iterator.hasNext()) {
beacon = iterator.next();
L.object(beacon);
entity.setId(null);
entity.setUuid(beacon.getId1().toString());
entity.setMajor(beacon.getId2().toString());
entity.setMinor(beacon.getId3().toString());
entity.setTxpower(beacon.getTxPower());
entity.setTime(Utils.getCurrentTime());
dbHelper.provideNinjaDao().insert(entity);
Log.d(TAG, "sql save success");
}
}
private Notification getNotification() {
CharSequence text = getText(R.string.notify_service_started);
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
Notification notification = new Notification.Builder(this)
.setSmallIcon(R.mipmap.ninja_turtle)
.setTicker(text)
.setWhen(System.currentTimeMillis())
.setContentTitle(getText(R.string.info_service))
.setContentText(text)
.setContentIntent(contentIntent)
.build();
return notification;
}
}
Hope you guys can help me. Thanks in advance.

Answer 1

A few points:
There are two different sets of settings for scan period using the Android Beacon Library, foreground and background. When using the BackgroundPowerSaver as shown in the code, the Android Beacon Library automatically switches back and forth between the foreground scan period and the background scan period.
When using the BackgroundPowerSaver, manually setting beaconManager.setBackgroundMode(true) will only have an effect until the next time the app cycles to the foreground -- the BackgroundPowerSaver will change the value of this setting automatically.
The units of the scan periods is milliseconds. So setting beaconManager.setBackgroundBetweenScanPeriod(20l); sets the scan period to be 20 milliseconds. This is way too short to pick up beacons reliably. I recommend a minimum scan period of 1100 ms. The longer the period, the higher probability of detecting a beacon, but the more battery is used.
If you want to wait 10 seconds between scans, you want to set: beaconManager.setBackgroundBetweenScanPeriod(10000l); // 10000 ms = 10.0 secs
If you want the same scan periods to apply both in the foreground and background, simply set them to be the same:
beaconManager.setBackgroundBetweenScanPeriod(10000l);
beaconManager.setForegroundBetweenScanPeriod(10000l);
beaconManager.setBackgroundScanPeriod(1100l);
beaconManager.setForegroundScanPeriod(1100l);