Headunit Reloaded emulator APK for Android Auto.
How to use the app?
USB Mode
Plug in the USB to your device (in case of tablet use an OTG cable), when prompted make sure you allow HUR to be the default app for the action and you check the always box.
If you are running the app on a device with Android 7.0 or higher, you might need to pull down the notification bar and select the connected USB device before the app starts (this is device dependent)
Wifi
Install WiFi Launcher app on the phone!
In WiFi Launcher select the cars BT, so app starts automatically
Enable hotspot option in WiFi Launcher, connect your car's unit to the phones hotspot and open HeadUnit Reloaded (you can reverse the hotspot / client roles as well if you wish)
Self Mode
Open HUR and press Self-mode (make sure you have Android Auto installed on the device you are trying to achieve this)