Android Bluetooth Pairing without User Enter Pin and Confirmation Using Android API

Question

I\'m a beginner in Android programming since I only started 3 months ago. I\'m doing a project which connects the android app to arduino using bluetooth. I already have a co

Answer 1

Yes this possible to do by code

In you main activity add the following code

BluetoothReceiver myreceiver = new BluetoothReceiver();
var intentfilterparingrequest = new IntentFilter(BluetoothDevice.ActionPairingRequest);
RegisterReceiver(myreceiver, intentfilterparingrequest);

In your broadcast receiver write following code, if not create a new broadcast receiver

public class BluetoothReceiver : BroadcastReceiver
{
    public override void OnReceive(Context context, Intent intent)
    {
        string BLE_PIN = "0000";
        var action = intent.Action;
        switch (action)
        {
            case BluetoothDevice.ActionPairingRequest:
                BluetoothDevice bluetoothDevice = 
              (BluetoothDevice)intent.GetParcelableExtra(BluetoothDevice.ExtraDevice);
                bluetoothDevice.SetPin(Encoding.ASCII.GetBytes(BLE_PIN));
                bluetoothDevice.CreateBond();
                break;
        }
    } 
}

Answer 2

First to clarify, this solution is designed for newer version of API (15 or later?)

I found the answer written in another post (see Roldofo's answer in Here). Here is my reorganized answer with detailed code.

In a nutshell, you need to setup a broadcast receiver to trap the ACTION_PAIRING_REQUEST, and then programmatically pass the PIN and confirm.

Register a broadcast receiver:

    IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_PAIRING_REQUEST);
    getActivity().registerReceiver(mPairingRequestReceiver, filter);

The definition of the receiver:

private final BroadcastReceiver mPairingRequestReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (action.equals(BluetoothDevice.ACTION_PAIRING_REQUEST)) {
            try {
                    BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                    int pin=intent.getIntExtra("android.bluetooth.device.extra.PAIRING_KEY", 1234);
                    //the pin in case you need to accept for an specific pin
                    Log.d(TAG, "Start Auto Pairing. PIN = " + intent.getIntExtra("android.bluetooth.device.extra.PAIRING_KEY",1234));
                    byte[] pinBytes;
                    pinBytes = (""+pin).getBytes("UTF-8");
                    device.setPin(pinBytes);
                    //setPairing confirmation if neeeded
                    device.setPairingConfirmation(true);
            } catch (Exception e) {
                Log.e(TAG, "Error occurs when trying to auto pair");
                e.printStackTrace();
            }
        }
    }
};

Then at your activity or fragment (wherever you want to initiate the pairing), you can call the following defined pairDevice() method to invoke pairing attempt (which will generate a ACTION_PAIRING_REQUEST)

private void pairDevice(BluetoothDevice device) {
    try {
        Log.d(TAG, "Start Pairing... with: " + device.getName());
        device.createBond();
        Log.d(TAG, "Pairing finished.");
    } catch (Exception e) {
        Log.e(TAG, e.getMessage());
    }
}

Answer 3

I also faced the same problem and after all the research, I figured out the below solution.

(Tested and working!!!)

I am basically looking for a particular bluetooth device (I know MAC address) and pair with it once found. The first thing to do is to create pair request using boradcast receiver and handle the request as below.

IntentFilter intentFilter = new IntentFilter(BluetoothDevice.ACTION_PAIRING_REQUEST);
                intentFilter.setPriority(IntentFilter.SYSTEM_HIGH_PRIORITY);
                registerReceiver(broadCastReceiver,intentFilter);

You need to write the broadcastReceiver and handle it as below.

String BLE_PIN = "1234"
private BroadcastReceiver broadCastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if(BluetoothDevice.ACTION_PAIRING_REQUEST.equals(action))
        {
            BluetoothDevice bluetoothDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            bluetoothDevice.setPin(BLE_PIN.getBytes());
            Log.e(TAG,"Auto-entering pin: " + BLE_PIN);
            bluetoothDevice.createBond();
            Log.e(TAG,"pin entered and request sent...");
        }
    }
};

Voila! You should be able to pair to bluetooth device without ANY MANUAL INTERVENTION.

Hope this helps :-) Please make it right answer if it works for you.