/**
  * Sets the duration in milliseconds spent not scanning between each Bluetooth LE scan cycle when
  * no ranging/monitoring clients are in the background. default 5 minutes
  *
  * @param p (ms)
  */
 public void setBackgroundBetweenScanPeriod(long p) {
   mBeaconManager.setBackgroundBetweenScanPeriod(p);
   try {
     mBeaconManager.updateScanPeriods(); // 保证在下一个循环扫描周期生效
   } catch (RemoteException e) {
     LogManager.d(TAG, "RemoteException:" + e.toString());
   }
 }
 @Override
 public void onActivityStopped(Activity activity) {
   if (activity instanceof ScannerActivity) {
     isScannerActivityResumed = false;
     scannerActivityDestroyedTimestamp = SystemClock.elapsedRealtime();
     long delayBetweenScans = getDelayBetweenScans();
     Timber.d("setBackgroundBetweenScanPeriod to %d ", delayBetweenScans);
     beaconManager.setBackgroundBetweenScanPeriod(delayBetweenScans);
     beaconManager.setBackgroundMode(true);
     Timber.d("setBackgroundMode");
   }
 }
 @Override
 public void onActivityResumed(Activity activity) {
   ++this.activeActivityCount;
   if (activity instanceof ScannerActivity) {
     beaconManager.setBackgroundMode(false);
     isScannerActivityResumed = true;
     // the scanner activity runs in foreground mode, fast scanning
     Timber.d("setForegroundMode");
   } else {
     // the app is still active but scan is backgrounded indefinitely
     beaconManager.setBackgroundBetweenScanPeriod(DELAY_FOREVER);
     isScannerActivityResumed = false;
     Timber.d("setBackgroundBetweenScanPeriod to %d ", DELAY_FOREVER);
     beaconManager.setBackgroundMode(true);
     Timber.d("setBackgroundMode");
   }
 }