To discover and pair Bluetooth Devices

Question

How to discover and pair Android Bluetooth devices using Java? Any codes for me to refer to?

Answer 1

the following code will discover the list of paired and the unpaired devices after that u have to implement the Client and server, which takes care of pairing the devices and sending data to the devices, for tat u can make use of the BluetoothChatSample which will give an idea to u.

private Set<BluetoothDevice> pairedDevices;
public static ArrayList<Object> BondedDeviceList;
public static ArrayList<Object> NewDeviceList;

 public void makeDiscoverable()
{
    discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
    discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
    activity.startActivity(discoverableIntent);
}

//It will Add the paired device in the BondedDeviceList
public void queryPairedDevice(){
    pairedDevices = mBluetoothAdapter.getBondedDevices();

    // If there are paired devices
    if(pairedDevices==null)
    {
        //No Bonded Devices 

    }else
    {
        if (pairedDevices.size() > 0) {
            // Loop through paired devices
            for (BluetoothDevice device : pairedDevices) {
                BondedDeviceList.add(device);
            }
            BondedDeviceList.add("End");
        }
    }
}

//Broadcast Receiver will find the Available devices and the discovery finished
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();

        // When discovery finds a device
        if (BluetoothDevice.ACTION_FOUND.equals(action.trim())) {
            // Get the BluetoothDevice object from the Intent
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            // If it's already paired, skip it, because it's been listed already
            if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
                NewDeviceList.add(device);
            }
            // When discovery is finished, change the Activity title
        } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
            if (NewDeviceList.isEmpty() == true) {
                String noDevices = "No Devices";
                NewDeviceList.add(noDevices);
            }
            System.out.println("Discovery Finished!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
            NewDeviceList.add("End");
        }
    }
};

//This is query for the bluetooth devices 
public void queryDevices(){
    actionFoundFilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
    activity.registerReceiver(mReceiver, actionFoundFilter);
    // Don't forget to unregister during onDestroy

    discoveryFinishedFilter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
    activity.registerReceiver(mReceiver, discoveryFinishedFilter); 
    // Don't forget to unregister during onDestroy
    queryPairedDevice();
    mBluetoothAdapter.startDiscovery();
}


//Unregister the receivers
public void unregisterReceiver() {
    // Make sure we're not doing discovery anymore
    if (mBluetoothAdapter != null) {
            mBluetoothAdapter.cancelDiscovery();
    }
    // Unregister broadcast listeners
    activity.unregisterReceiver(mReceiver);
}

Cheers.