Android + Pair devices via bluetooth programmatically

In my first answer the logic is shown for those who want to go with the logic only.

I think I was not able to make clear to @chalukya3545, that's why I am adding the whole code to let him know the exact flow of the code.

BluetoothDemo.java

public class BluetoothDemo extends Activity {

    ListView listViewPaired;
    ListView listViewDetected;
    ArrayList<String> arrayListpaired;
    Button buttonSearch,buttonOn,buttonDesc,buttonOff;
    ArrayAdapter<String> adapter,detectedAdapter;
    static HandleSeacrh handleSeacrh;
    BluetoothDevice bdDevice;
    BluetoothClass bdClass;
    ArrayList<BluetoothDevice> arrayListPairedBluetoothDevices;
    private ButtonClicked clicked;
    ListItemClickedonPaired listItemClickedonPaired;
    BluetoothAdapter bluetoothAdapter = null;
    ArrayList<BluetoothDevice> arrayListBluetoothDevices = null;
    ListItemClicked listItemClicked;

    @Override 
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        listViewDetected = (ListView) findViewById(R.id.listViewDetected);
        listViewPaired = (ListView) findViewById(R.id.listViewPaired);
        buttonSearch = (Button) findViewById(R.id.buttonSearch);
        buttonOn = (Button) findViewById(R.id.buttonOn);
        buttonDesc = (Button) findViewById(R.id.buttonDesc);
        buttonOff = (Button) findViewById(R.id.buttonOff); 
        arrayListpaired = new ArrayList<String>();
        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        clicked = new ButtonClicked();
        handleSeacrh = new HandleSeacrh();
        arrayListPairedBluetoothDevices = new ArrayList<BluetoothDevice>();
        /*
         * the above declaration is just for getting the paired bluetooth devices;
         * this helps in the removing the bond between paired devices.
         */
        listItemClickedonPaired = new ListItemClickedonPaired();
        arrayListBluetoothDevices = new ArrayList<BluetoothDevice>();
        adapter= new ArrayAdapter<String>(BluetoothDemo.this, android.R.layout.simple_list_item_1, arrayListpaired);
        detectedAdapter = new ArrayAdapter<String>(BluetoothDemo.this, android.R.layout.simple_list_item_single_choice);
        listViewDetected.setAdapter(detectedAdapter);
        listItemClicked = new ListItemClicked();
        detectedAdapter.notifyDataSetChanged();
        listViewPaired.setAdapter(adapter);
    }

    @Override
    protected void onStart() {
        // TODO Auto-generated method stub
        super.onStart();
        getPairedDevices();
        buttonOn.setOnClickListener(clicked);
        buttonSearch.setOnClickListener(clicked);
        buttonDesc.setOnClickListener(clicked);
        buttonOff.setOnClickListener(clicked);
        listViewDetected.setOnItemClickListener(listItemClicked);
        listViewPaired.setOnItemClickListener(listItemClickedonPaired);
    }
    private void getPairedDevices() {
        Set<BluetoothDevice> pairedDevice = bluetoothAdapter.getBondedDevices();            
        if(pairedDevice.size()>0)
        {
            for(BluetoothDevice device : pairedDevice)
            {
                arrayListpaired.add(device.getName()+"\n"+device.getAddress());
                arrayListPairedBluetoothDevices.add(device);
            }
        }
        adapter.notifyDataSetChanged();
    }
    class ListItemClicked implements OnItemClickListener
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            // TODO Auto-generated method stub
            bdDevice = arrayListBluetoothDevices.get(position);
            //bdClass = arrayListBluetoothDevices.get(position);
            Log.i("Log", "The dvice : "+bdDevice.toString());
            /*
             * here below we can do pairing without calling the callthread(), we can directly call the
             * connect(). but for the safer side we must usethe threading object.
             */
            //callThread();
            //connect(bdDevice);
            Boolean isBonded = false;
            try {
                isBonded = createBond(bdDevice);
                if(isBonded)
                {
                    //arrayListpaired.add(bdDevice.getName()+"\n"+bdDevice.getAddress());
                    //adapter.notifyDataSetChanged();
                    getPairedDevices();
                    adapter.notifyDataSetChanged();
                }
            } catch (Exception e) {
                e.printStackTrace(); 
            }//connect(bdDevice);
            Log.i("Log", "The bond is created: "+isBonded);
        }       
    }
    class ListItemClickedonPaired implements OnItemClickListener
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
            bdDevice = arrayListPairedBluetoothDevices.get(position);
            try {
                Boolean removeBonding = removeBond(bdDevice);
                if(removeBonding)
                {
                    arrayListpaired.remove(position);
                    adapter.notifyDataSetChanged();
                }


                Log.i("Log", "Removed"+removeBonding);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    /*private void callThread() {
        new Thread(){
            public void run() {
                Boolean isBonded = false;
                try {
                    isBonded = createBond(bdDevice);
                    if(isBonded)
                    {
                        arrayListpaired.add(bdDevice.getName()+"\n"+bdDevice.getAddress());
                        adapter.notifyDataSetChanged();
                    }
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace(); 
                }//connect(bdDevice);
                Log.i("Log", "The bond is created: "+isBonded);
            }           
        }.start();
    }*/
    private Boolean connect(BluetoothDevice bdDevice) { 
        Boolean bool = false;
        try {
            Log.i("Log", "service method is called ");
            Class cl = Class.forName("android.bluetooth.BluetoothDevice");
            Class[] par = {};
            Method method = cl.getMethod("createBond", par);
            Object[] args = {};
            bool = (Boolean) method.invoke(bdDevice);//, args);// this invoke creates the detected devices paired.
            //Log.i("Log", "This is: "+bool.booleanValue());
            //Log.i("Log", "devicesss: "+bdDevice.getName());
        } catch (Exception e) {
            Log.i("Log", "Inside catch of serviceFromDevice Method");
            e.printStackTrace();
        }
        return bool.booleanValue();
    };


    public boolean removeBond(BluetoothDevice btDevice)  
    throws Exception  
    {  
        Class btClass = Class.forName("android.bluetooth.BluetoothDevice");
        Method removeBondMethod = btClass.getMethod("removeBond");  
        Boolean returnValue = (Boolean) removeBondMethod.invoke(btDevice);  
        return returnValue.booleanValue();  
    }


    public boolean createBond(BluetoothDevice btDevice)  
    throws Exception  
    { 
        Class class1 = Class.forName("android.bluetooth.BluetoothDevice");
        Method createBondMethod = class1.getMethod("createBond");  
        Boolean returnValue = (Boolean) createBondMethod.invoke(btDevice);  
        return returnValue.booleanValue();  
    }  


    class ButtonClicked implements OnClickListener
    {
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
            case R.id.buttonOn:
                onBluetooth();
                break;
            case R.id.buttonSearch:
                arrayListBluetoothDevices.clear();
                startSearching();
                break;
            case R.id.buttonDesc:
                makeDiscoverable();
                break;
            case R.id.buttonOff:
                offBluetooth();
                break;
            default:
                break;
            }
        }
    }
    private BroadcastReceiver myReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Message msg = Message.obtain();
            String action = intent.getAction();
            if(BluetoothDevice.ACTION_FOUND.equals(action)){
                Toast.makeText(context, "ACTION_FOUND", Toast.LENGTH_SHORT).show();

                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                try
                {
                    //device.getClass().getMethod("setPairingConfirmation", boolean.class).invoke(device, true);
                    //device.getClass().getMethod("cancelPairingUserInput", boolean.class).invoke(device);
                }
                catch (Exception e) {
                    Log.i("Log", "Inside the exception: ");
                    e.printStackTrace();
                }

                if(arrayListBluetoothDevices.size()<1) // this checks if the size of bluetooth device is 0,then add the
                {                                           // device to the arraylist.
                    detectedAdapter.add(device.getName()+"\n"+device.getAddress());
                    arrayListBluetoothDevices.add(device);
                    detectedAdapter.notifyDataSetChanged();
                }
                else
                {
                    boolean flag = true;    // flag to indicate that particular device is already in the arlist or not
                    for(int i = 0; i<arrayListBluetoothDevices.size();i++)
                    {
                        if(device.getAddress().equals(arrayListBluetoothDevices.get(i).getAddress()))
                        {
                            flag = false;
                        }
                    }
                    if(flag == true)
                    {
                        detectedAdapter.add(device.getName()+"\n"+device.getAddress());
                        arrayListBluetoothDevices.add(device);
                        detectedAdapter.notifyDataSetChanged();
                    }
                }
            }           
        }
    };
    private void startSearching() {
        Log.i("Log", "in the start searching method");
        IntentFilter intentFilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        BluetoothDemo.this.registerReceiver(myReceiver, intentFilter);
        bluetoothAdapter.startDiscovery();
    }
    private void onBluetooth() {
        if(!bluetoothAdapter.isEnabled())
        {
            bluetoothAdapter.enable();
            Log.i("Log", "Bluetooth is Enabled");
        }
    }
    private void offBluetooth() {
        if(bluetoothAdapter.isEnabled())
        {
            bluetoothAdapter.disable();
        }
    }
    private void makeDiscoverable() {
        Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
        discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
        startActivity(discoverableIntent);
        Log.i("Log", "Discoverable ");
    }
    class HandleSeacrh extends Handler
    {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
            case 111:

                break;

            default:
                break;
            }
        }
    }
}

Here is the main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button 
        android:id="@+id/buttonOn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="On"/>
    <Button 
        android:id="@+id/buttonDesc"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Make Discoverable"/>
   <Button 
       android:id="@+id/buttonSearch"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:text="Search"/>
   <Button 
       android:id="@+id/buttonOff"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:text="Bluetooth Off"/>

   <ListView 
       android:id="@+id/listViewPaired"
       android:layout_width="match_parent"
       android:layout_height="120dp">

   </ListView>

   <ListView 
       android:id="@+id/listViewDetected"
       android:layout_width="match_parent"
       android:layout_height="match_parent">

   </ListView>
</LinearLayout>

Add this permissions to your AndroidManifest.xml file:

 <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
 <uses-permission android:name="android.permission.BLUETOOTH" />  
 <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

The output for this code will look like this. Bluutooth Demo


The Best way is do not use any pairing code. Instead of onClick go to other function or other class where You create the socket using UUID.
Android automatically pops up for pairing if already not paired.

or see this link for better understanding

Below is code for the same:

private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
    public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
        // Cancel discovery because it's costly and we're about to connect
        mBtAdapter.cancelDiscovery();

        // Get the device MAC address, which is the last 17 chars in the View
        String info = ((TextView) v).getText().toString();
        String address = info.substring(info.length() - 17);

        // Create the result Intent and include the MAC address
        Intent intent = new Intent();
        intent.putExtra(EXTRA_DEVICE_ADDRESS, address);

        // Set result and finish this Activity
        setResult(Activity.RESULT_OK, intent);

      // **add this 2 line code** 
       Intent myIntent = new Intent(view.getContext(), Connect.class);
        startActivityForResult(myIntent, 0);

        finish();
    }
};

Connect.java file is :

public class Connect extends Activity {
private static final String TAG = "zeoconnect";
private ByteBuffer localByteBuffer;
 private InputStream in;
 byte[] arrayOfByte = new byte[4096];
 int bytes;


  public BluetoothDevice mDevice;



@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.connect);



              try {
                setup();
            } catch (ZeoMessageException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (ZeoMessageParseException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            }

 private void setup() throws ZeoMessageException, ZeoMessageParseException  {
    // TODO Auto-generated method stub

        getApplicationContext().registerReceiver(receiver,
                    new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED));
        getApplicationContext().registerReceiver(receiver,
                    new IntentFilter(BluetoothDevice.ACTION_ACL_DISCONNECTED));

            BluetoothDevice zee = BluetoothAdapter.getDefaultAdapter().
                    getRemoteDevice("**:**:**:**:**:**");// add device mac adress

            try {
                sock = zee.createRfcommSocketToServiceRecord(
                         UUID.fromString("*******************")); // use unique UUID
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }

            Log.d(TAG, "++++ Connecting");
            try {
                sock.connect();
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            Log.d(TAG, "++++ Connected");


            try {
                in = sock.getInputStream();
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }

              Log.d(TAG, "++++ Listening...");

              while (true) {

                  try {
                      bytes = in.read(arrayOfByte);
                      Log.d(TAG, "++++ Read "+ bytes +" bytes");  
                    } catch (IOException e1) {
                        // TODO Auto-generated catch block
                        e1.printStackTrace();
                }
                        Log.d(TAG, "++++ Done: test()"); 

                        }} 




 private static final LogBroadcastReceiver receiver = new LogBroadcastReceiver();
    public static class LogBroadcastReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context paramAnonymousContext, Intent paramAnonymousIntent) {
            Log.d("ZeoReceiver", paramAnonymousIntent.toString());
            Bundle extras = paramAnonymousIntent.getExtras();
            for (String k : extras.keySet()) {
                Log.d("ZeoReceiver", "    Extra: "+ extras.get(k).toString());
            }
        }


    };

    private BluetoothSocket sock;
    @Override
    public void onDestroy() {
        getApplicationContext().unregisterReceiver(receiver);
        if (sock != null) {
            try {
                sock.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        super.onDestroy();
    }
 }

if you have the BluetoothDevice object you can create bond(pair) from api 19 onwards with bluetoothDevice.createBond() method.

Edit

for callback, if the request was accepted or denied you will have to create a BroadcastReceiver with BluetoothDevice.ACTION_BOND_STATE_CHANGED action