BluetoothAdapter won't stop scanning for BLE devices

Question

In my app i have start and stop button, when user press start i call startScan method

bluetoothAdapter.getBluetoothLeScanner().startScan(getLeScanCallback());

When user press stop i call stopScan however it doesn't seem to do anything. BluetoothAdapter keeps scanning for new devices.

bluetoothAdapter.getBluetoothLeScanner().stopScan(getLeScanCallback());

Here is my getLeScanCallback method:

private ScanCallback getLeScanCallback(){
    ScanCallback leScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {
            super.onScanResult(callbackType, result);
            boolean duplicate = false;
            for(Device d : devices) {
                if(d.getAddress().equals(result.getDevice().getAddress()))
                    duplicate = true;
            }
            if(!duplicate) {
                Device device = new Device();
                device.setName(result.getDevice().getName());
                device.setAddress(result.getDevice().getAddress());
                device.setStatus(getString(R.string.disconnected));
                devices.add(device);
                deviceListAdapter.notifyDataSetChanged();
            }
        }

        @Override
        public void onBatchScanResults(List<ScanResult> results) {
            super.onBatchScanResults(results);
        }

        @Override
        public void onScanFailed(int errorCode) {
            super.onScanFailed(errorCode);
        }
    };

    return leScanCallback;
}

It gets called even after stopScan() was called. What am I doing wrong or in other words, how to stop scanning for BLE devices?

Answer 1

Every time you call getLeScanCallback you create new instance of ScanCallback and lost reference to previous instance.

stopScan stops ongoing scan regardless what instance you pass BUT if it is a different instance (than the one you used to start) it will not remove old instance of callback so still some events will be delivered to it before it stops.