Blutooth LE Scan

Question

I am developing a demo app to scan Blutooth Le devices. But startLeScan() returns null. and I am not getting any device name. I have tried using normal scan it shows up fine. I am adding my snippet here

private void scanLeDevice(final boolean enable) {
        if (enable) {
            // Stops scanning after a pre-defined scan period.
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    mScanning = false;
                    mTxtInfo.setText("Stopped Scanning.");
                    mBluetoothAdapter.stopLeScan(mLeScanCallback);
                }
            }, SCAN_PERIOD);

            mScanning = true;
            mTxtInfo.setText("Started Scanning...");
            mBluetoothAdapter.startLeScan(mLeScanCallback);
        } else {
            mTxtInfo.setText("Stopped Scanning.");
            mScanning = false;
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        }

    }

This is my function to start Le scan.

// Device scan callback.
    private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {
        @Override
        public void onLeScan(final BluetoothDevice device, int rssi,
                byte[] scanRecord) {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {

                    mTxtInfo.setText("Detected devices: " + device.getName());
                    Toast.makeText(MainActivity.this,
                            "Detected devices: " + device.getName(),
                            Toast.LENGTH_LONG).show();
                }
            });
        }


    };

this is the callback. And its showing me

07-04 12:50:17.833: D/BluetoothAdapter(3564): startLeScan(): null

Would appreciate any help.

Answer 1

The Problem there is that you are trying to use

startLeScan(callback) 

without setting the Uuid parameter. So the BluetoothAdapter code it's doing something like:

startLeScan(null, callback) 

on the back and printing

"startLeScan:" + Uuid. 

Which for you is null.