How to receive intents for Bluetooth devices working?

Question

I'm trying to have my app's service listen for Bluetooth connection and disconnection attempts, so I can dynamically check/support Bluetooth tethering network communication.

First I have two Samsung S4s (running CyanogenMod 10.2, which is Android 4.3.1 based) which I can pair just fine. If I set one device to Bluetooth tether, when the other connects, a new bt-pan network interface is created and DHCP is used to assign IPs. I confirmed this using iwconfig and ifconfig in shell.

I have the following perms in my app: (there's more, I'm just pointing out the BT perms I added)

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

Here's my Service's onCreate where I set my IntentFilters: (note I've got Toasts here, but I was working with Logging originally)

@Override
public void onCreate() {
    super.onCreate();
    ...     
    this.mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);
    IntentFilter filter = new IntentFilter();
    filter.addAction(BluetoothDevice.ACTION_FOUND);
    filter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
    filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);
    filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECT_REQUESTED);

    mLocalBroadcastManager.registerReceiver(mMessageReceiver, filter);
}

Here's my BroadcastReceiver implementation:

private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if(action.equals(BluetoothDevice.ACTION_FOUND)) {
            Toast.makeText(getApplicationContext(), "BT found", Toast.LENGTH_SHORT).show();
        } else if(action.equals(BluetoothDevice.ACTION_ACL_CONNECTED)) {
            Toast.makeText(getApplicationContext(), "BT Connected", 
        } else if(action.equals(BluetoothDevice.ACTION_ACL_DISCONNECTED)) {
            Toast.makeText(getApplicationContext(), "BT Disconnected", Toast.LENGTH_SHORT).show();
        } else
            Toast.makeText(getApplicationContext(), "BT Disconnect requested", Toast.LENGTH_SHORT).show();
        }
    }
}

Now, when I turn Bluetooth off/on, connect/disconnect to a paired device, nothing fires. I've payed around with the devices from both ends. Nothing is broadcast.

Anyone have a suggestion? I really need to receive these bluetooth events. Please don't point to another post/site with the same perms and intent filters. Thanks.

Answer 1

I have a very similar code which works, the only major difference i found was this:

mLocalBroadcastManager.registerReceiver(mMessageReceiver, filter);

i beleive that registerReceiver should be called from the context you want to get intents to. try calling the method from this. i.e remove the mLocalBroadcastManager like:

registerReceiver(mMessageReceiver, filter);

Answer 2

If you Register the Receiver on the Manifest instead of the Activity, you can receive broadcasts even if you do not have the app opened, you can do this:

    <receiver android:name=".BluetoothReceiver" >
        <intent-filter>
            <action android:name="android.bluetooth.device.action.ACL_CONNECTED" />
            <action android:name="android.bluetooth.device.action.BOND_STATE_CHANGED" />
        </intent-filter>
    </receiver>