I know this has been answered but just in case someone else wants this info. There are two ways to enable bluetooth one is to use the Intents and send a user request
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
second is to just call the enable method on the adapter, only use this method if user input is not needed or wanted.
BluetoothAdapter blue = BluetoothAdapter.getDefaultAdapter();
to disable you just call disable method on adapter.