Can't you really understand me? There is a so-called audio focus function. If one media app is played and another is switched on later, the one that was switched on later asks the system if it can interrupt the app that was started first. And that's exactly what doesn't work with the DuDu!
You have only saved the time where DriveCast used to stop playing. This is an improvement but not the desired one.
Your system also runs Android, doesn't it? Other head units that also run Android do it right. One media app asks if it can interrupt the other and the system then allows it. I don't really know what's so difficult to understand about it.
Here are the different types of focus for understanding.
Focus types (example Android):
AUDIOFOCUS_GAIN: The app receives exclusive Focus and is allowed to play undisturbed. Other apps are interrupted or mixed more quietly.
AUDIOFOCUS_GAIN_TRANSIENT: The app receives Focus for a short time (e.g. for a notification). Other apps are not interrupted, but only mixed quietly.
AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK: The app is allowed to continue running quietly, while the new app receives Focus. The new app only "ducks" the existing app instead of interrupting it.
AUDIOFOCUS_LOSS: The app loses Focus and needs to react (e.g., pause or stop).
AUDIOFOCUS_LOSS_TRANSIENT: The app temporarily loses Focus (e.g. for a call). It should pause, but not stop.
AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK: The app temporarily loses Focus and may continue to run quietly (e.g. background music).
DriveCast sends the the Audiofocus_LOSS_Transient mode. Presumably, the app is only missing a permission in the system. As I said in other head units I tested, it works, but not with the DuDu!
