I have a 2015 Audi car with a non internet connected media centre. Audi MMI. The media centre has a Wi-Fi Access Point to enable Wi-Fi music players to stream to the car. If I connect my S7 phone to the car AP the phone will connect, and correctly show the text "Internet may not be available", as the car has no SIM or mobile module, just bluetooth. What happens next is a proprietary Audi app running on my phone in the background, "Audi MMI connect" attempts to establish a DNLA server from the phone to car, but it never gets any further.
I have got it work, but only by disabling Mobile Data on the phone. With this disabled it seems the phone takes up an IP address served by the car AP subnet. The MMI then reads the music files off the phone and presents them on the car interface. If I leave mobile data connected or reconnect it while serving to the AP the connection is lost at the end of the playing track.
It also means when I exit the car I have to remember to turn mobile data back on to regain email, whatsapp etc.
Firstly, is there any way I can have mobile data turn off when a particular Wi-Fi AP is connected, even though it has no Internet connection, then turn mobile data on again on disconnection from the AP.
Second, is there any way I can set the phone IP to reflect that of the AP subnet, even if mobile data is turned on.