Using getConnectedDevices() to get the BLE connected Device is not working in Android 4.3

Question

I am developing an application where I have to connect to Bluetooth device on Android 4.3.

And I want to use getConnectedDevices() like the following code to get the connected Device after connect BLE device using by mBluetoothGatt.connect(), but is not working.

    @Override
    public void onServiceDisconnected(int profile) {
        // TODO Auto-generated method stub
        Log.v(TAG, "profile1" + profile);
        Log.v(TAG, "BluetoothProfile.HEADSET1 = " + BluetoothProfile.HEADSET);
        if(profile == BluetoothProfile.HEADSET) {
            mBluetoothHeadset  = null;
        }
    }

    @Override
    public void onServiceConnected(int profile, BluetoothProfile proxy) {
        // TODO Auto-generated method stub
        Log.v(TAG, "profile2 " + profile);
        Log.v(TAG, "BluetoothProfile.HEADSET2 = " + BluetoothProfile.HEADSET);
        if(profile == BluetoothProfile.HEADSET) {
            mBluetoothHeadset  = (BluetoothHeadset) proxy;

            Log.v(TAG, "mBluetoothHeadset = " + mBluetoothHeadset);
            List<BluetoothDevice> devicelist = mBluetoothHeadset.getConnectedDevices();
            Log.v(TAG, "mBluetoothHeadset.getConnectedDevices = " + mBluetoothHeadset.getConnectedDevices());
            Log.v(TAG, "devicelist = " + devicelist);
            for(BluetoothDevice dev : devicelist) {
                Log.v(TAG, "connectedDevices = " + dev);
            }
        }
    }
    };



@Override
    protected void onNewIntent(Intent intent) {
        // TODO Auto-generated method stub
        super.onNewIntent(intent);
        setIntent(intent);

    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    mBluetoothAdapter.getProfileProxy(Main.this, mProfileListener, BluetoothProfile.HEADSET);




}

and seen from the log , it didn't call the function getConnectedDevices(); The Log is:

D/BluetoothHeadset( 3454): Proxy object connected
V/Main    ( 3454): profile2 = 1
V/Main    ( 3454): BluetoothProfile.HEADSET2 = 1
V/Main    ( 3454): mBluetoothHeadset = android.bluetooth.BluetoothHeadset@4a99cddc
V/Main    ( 3454): mBluetoothHeadset.getConnectedDevices = []
V/Main    ( 3454): devicelist = []

The list of connected is empty , and I'm sure I have one connected BLE device. Does it something wrong in my code ??