Difference in Bluetooth scanning and discovery on Android

Question

There are two approaches defined in the Android to find out bluetooth devices. 1. Using bluetoothAdapter.startScan 2. bluetoothAdapter.discover

which approach is better.

2nd question, In onLeScan callback, how to check if scanning has been stopped.

Answer 1

These methods apply to different versions of Bluetooth. Which one to use depends on what kind of device you have.

Classic Bluetooth uses BluetoothAdapter.startDiscovery() to find devices which are discoverable.

Bluetooth Low Energy support was added in API level 18, it uses BluetoothAdapter.startLeScan(ScanCallback). As of API level 21 this is replaced by BluetoothLeScanner.startScan().

See this samplecode on how to scan for LE devices. In onLeScan if you've found the device just call scanLeDevice(false);.

The onLeScan callback does not check if scanning has been stopped. You have to give the stopLeScan() command yourself.

Answer 2

startScan() will be scanning for LE devices, startDiscovery() for normal bluetooth devices.

As far I know startLeScan() or startScan() will scan as long as method stopLeScan() or stopScan() will be called and you must call them.