Doubts with BroadcastReceiver on Adroid

I am using the following code:

private boolean statusUSB = false;

private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {

    public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();

        if (action != null) {

            switch (action) {
                case UsbManager.ACTION_USB_DEVICE_DETACHED:
                    final UsbDevice detDevice = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                    final String detMsg="Device DEtached";
                    statusUSB = false;
                    Toast.makeText(context, "USB Disconnected", Toast.LENGTH_SHORT).show();
                    break;
                case UsbManager.ACTION_USB_DEVICE_ATTACHED:
                case UsbManager.ACTION_USB_ACCESSORY_ATTACHED:
                    final UsbDevice attDevice = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                    final String attMsg="Device atached";
                    statusUSB = true;
                    Toast.makeText(context, "USB Connected", Toast.LENGTH_SHORT).show();
                    break;
                default:
                    break;
            }
        }
    }
};

To detect when the USB port is connected or disconnected, apart from that I have also inserted a flag:

statusUSB = true/false

Then use it in my menu

 @Override
public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate( R.menu.main, menu );

    if (statusUSB == true){
        // Opcion1
    }
    if (statusUSB == false){
        //Opcion2
    }

    return true;
}

The fact is that Android detects both conditions when the USB port is connected and disconnected, but the flag does not change or I can not read this value in my menu, I am doing well or there is another way to feed this flag