问题
Android Lollipop introduced a new way to scan for BLE peripherals, via BluetoothLeScanner.
From what I read, the new scanning API solved an issue that happened with the old scanning API (BluetoothAdapter.startLeScan(UUID[],LeScanCallback)) where on some devices the callback (onLeScan) was called only once per peripheral, even if the peripheral keeps advertising.
This issue is handled on iOS with the CBCentralManagerScanOptionAllowDuplicatesKey option, that allows you to choose whether you want to detect only new peripherals or keep getting advertisements from previously-found peripherals.
Is there a similar option in the new Android Lollipop API? i.e. decide that you want the callback to be called only for new peripherals (new MAC addresses) and not called twice for the same peripheral.
I know that it could easily be implemented by saving a list\set of all the MAC addresses that were previously received - but this way does not take advantage of hardware optimizations.
来源：https://stackoverflow.com/questions/30512976/android-lollipop-ble-scan-getting-peripherals-without-duplications