the notifications are popping up almost instantly ( despite me providing time for it ).
you pass the time you want it to be triggered from now on. The API expects a time since EPOCH (as your comment in the code also states) which are the milliseconds from 1970/01/01 on.
So in your JAVA code add new Date().getTime() milliseconds to your current timeout.
So far i am able to get the notifications ( but not on Android O )
did you read this already?
Alos chekc the Qt debugger console and/or LogCat for suspicious messages regarding notifications.
I run in the same paradigm when I try to create a static linked library with Qt targeting Android and latter to use it with JINI on Android Studio.
Reading you post I see you have almost the same problem like me with one difference.
To me are working as far I use only std library
My problem appears when I use QString for example in the library.
Looks the static build does not statically includes the Qt framework dependencies.
Finally did you find a solution? Me I run with this issue past over one month.