Flutter Android Alarm Manager not working - dart

Question

I have installed the Android Alarm Manager plugin in my Flutter v1.0.0 app by following the instructions at the link. But when I try to use AndroidAlarmManager.oneShot(...) nothing happens. There's not even an error in the console.
I am using a FutureBuilder widget to wait on the AndroidAlarmManager.initialize() future and one other future before my app begins rendering:
final combinedFutures = Future.wait<void>([
gameService.asyncLoad(),
AndroidAlarmManager.initialize(),
]);
FutureBuilder<void>(
future: combinedFutures,
builder: (context, snapshot) {
...
}
)
The FutureBuilder does end up rendering what it should so I know that the AndroidAlarmManager.initialize() future returns correctly.
Then in a button's onPressed function I do this:
AndroidAlarmManager.oneShot(
Duration(seconds: 5),
0,
() {
print("test");
},
wakeup: true,
);
The above should be calling print(test) after 5 seconds and waking up my phone but nothing is printed to the console and nothing happens on my phone. What is going wrong?

Answer 1

After debugging the library code I found that the AndroidAlarmManager.oneShot function calls the method PluginUtilities.getCallbackHandle(callback) where callback is the function passed in. In my case the callback function was:
() {
print("test");
}
For some reason PluginUtilities.getCallbackHandle was returning null when it should be returning a value of type CallbackHandle.
Looking at the PluginUtilities.getCallbackHandle documentation it says:
Get a handle to a named top-level or static callback function which can be easily passed between isolates.
The function I was passing is not top-level, static, or named. So I did the following inside my class and everything works fine now:
static void alarmTest() {
print("test");
}
void runAlarm() {
AndroidAlarmManager.oneShot(
Duration(seconds: 10),
0,
alarmTest,
wakeup: true,
).then((val) => print(val));
}