How to periodically scan for bluetooth devices on android

Question

Hi this may sound as a stupid question.But I was unable to find any answers for this, thus posting here.

I am building an indoor application which continuously scans the bluetooth dongles located at different locations in a place like a mall or library.As I move in the mall with android phone in my hand I should be able to get the nearest dongle which I can connect to(Stupid Idea but I want to do something else with this).For this I should be able to continuously scan for the bluetooth devices.

Please can someone tell me how do I make android scan the available Bluetooth devices periodically.

Answer 1

I guess this was so simple but dint strike me before.Here is the answer,

private BluetoothAdapter mBtAdapter;
mBtAdapter.startDiscovery();

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)) {
            //do something
}

            else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                Log.v(TAG,"Entered the Finished ");
                mBtAdapter.startDiscovery();
}

Thus we should start discovery again on ACTION_DISCOVERY_FINISHED which will continuously scan for devices every 12 seconds.

Answer 2

Your code snippet should work - Only that it will be expensive in terms of power draw and will certainly kill your device/phone in a few hours. The startDiscovery() does a 2 step process, finding the device by inquiring for it and followed by a name discovery ie paging and connecting to the device,

Unfortunately Android does not provide any API to control this and do only inquiry , also there is a periodic inquiry feature defined and supported by most Bluetooth chipsets, Android currently does not have any API to do periodic inquiry which could have been more ideal for your use case.