can show devices

Build OK
Run OK
GPS Permission OK
Central -> Search.. No device shown. -> could not find callback wrapper

D/BluetoothLeScanner: startScan
D/BluetoothAdapter: getLeState() returning 12
    STATE_ON
D/BluetoothAdapter: getLeState() returning 12
D/BluetoothLeScanner: onClientRegistered() - status=0 clientIf=8
    mClientIf=0
I/BluetoothLeScanner: startRegisteration: mLeScanClients={org.zpcat.ble.data.BLEDataServer$1@b2ab48f=android.bluetooth.le.BluetoothLeScanner$BleScanCallbackWrapper@2f609ec}
I/art: Enter while loop.
D/BluetoothLeScanner: stopScan
D/BluetoothAdapter: getLeState() returning 12
    STATE_ON
I/BluetoothLeScanner: startRegisteration: mLeScanClients={org.zpcat.ble.data.BLEDataServer$1@b2ab48f=android.bluetooth.le.BluetoothLeScanner$BleScanCallbackWrapper@2f609ec} ,callback=org.zpcat.ble.data.BLEDataServer$1@b2ab48f