How to programmatically tell if a Bluetooth device is connected?

Question

I understand how to get a list of paired devices but how can I tell if they are connected?

It must be possible since I see them listed in my phone\'s Bluetooth devi

Answer 1

This code is for the headset profiles, probably it will work for other profiles too. First you need to provide profile listener (Kotlin code):

private val mProfileListener = object : BluetoothProfile.ServiceListener {
    override fun onServiceConnected(profile: Int, proxy: BluetoothProfile) {
        if (profile == BluetoothProfile.HEADSET) 
            mBluetoothHeadset = proxy as BluetoothHeadset            
    }

    override fun onServiceDisconnected(profile: Int) {
        if (profile == BluetoothProfile.HEADSET) {
            mBluetoothHeadset = null
        }
    }
}

Then while checking bluetooth:

mBluetoothAdapter.getProfileProxy(context, mProfileListener, BluetoothProfile.HEADSET)
if (!mBluetoothAdapter.isEnabled) {
    return Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE)
}

It takes a bit of time until onSeviceConnected is called. After that you may get the list of the connected headset devices from:

mBluetoothHeadset!!.connectedDevices