Question

I made a helper class that extends BroadcastReceiver to listen for BluetoothDevice found and discovery finish intents. I have two activities which use this class by passing a handler. The handler receives messages as per the intent. I instantiate the class and registerReceiver like this:

From mainActivity:

deviceHelper=new DevicesHelper(myHandler,DevicesHelper.REQUEST_DETECT_DEVICES_IN_RANGE);

IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(deviceHelper, filter);

filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
this.registerReceiver(deviceHelper, filter);

if(myBluetoothAdapter.isDiscovering())myBluetoothAdapter.cancelDiscovery();
myBluetoothAdapter.startDiscovery(); 

From ListActivity:

deviceHelper=new DevicesHelper(deviceListHandler,DevicesHelper.REQUEST_DEVICE_LIST_ACTIVITY);

IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(deviceHelper, filter);

filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
this.registerReceiver(deviceHelper, filter);

DeviceHelper class:

public class DevicesHelper extends BroadcastReceiver {

    public final static int REQUEST_DEVICE_LIST_ACTIVITY=1;
    public final static int REQUEST_DETECT_DEVICES_IN_RANGE=2;


    Handler myHandler;      
    int requestCode;

    public DevicesHelper(){

    }
    public DevicesHelper(Handler handler,int requestCode){
            this.requestCode=requestCode;
            myHandler=handler;

    }

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        String action = intent.getAction();

        // When discovery finds a device
        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

        if (BluetoothDevice.ACTION_FOUND.equals(action)) {
            // Get the BluetoothDevice object from the Intent
            switch(requestCode){
            case REQUEST_DEVICE_LIST_ACTIVITY: 
                if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
                    //newDevicesCount++;
                    String[] deviceInfo={device.getName(),device.getAddress()};

                    myHandler.obtainMessage(DeviceListActivity.MESSAGE_NEW_DEVICE,deviceInfo);
                };


                break;

            case REQUEST_DETECT_DEVICES_IN_RANGE:

                String[] deviceInfo={device.getName(),device.getAddress()};

                myHandler.obtainMessage(StripChartRecorder.MESSAGE_NEW_DEVICE,deviceInfo);
                break;

            }


            // When discovery is finished, change the Activity title
        } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {

            myHandler.obtainMessage(StripChartRecorder.MESSAGE_DISCOVERY_FINISHED);

        }
    }

Handler:

private final Handler myHandler=new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch(msg.what) {
                case MESSAGE_NEW_DEVICE:
                    doOtherStuff();

                case MESSAGE_DISCOVERY_FINISHED:
                    dostuff();
            }
            break;
}}

Am I missing something here? I appreciate any help.

Answer 1

The problem was how I was handling the message received from the handler. Turned out Set<> was initially set to null as per eclipse’s instruction, so it was never adding the devices received from the BroadcastReceiver helper class. I appreciate anyone who tried to help.