alarm listener doesn't fire if app is in foreground (Android only)

[ApplySci]

Alarm plugin version
5.0.0-dev.4 and 4.1.1

Describe the bug
If the app is in the foreground when an alarm goes off, I get a notification. But the alarm listener doesn't get triggered. I'm using Alarm.ringStream.stream.listen(openAlarmPage), but that doesn't get triggered when an alarm starts ringing. In the debug console, I do see Flutter was notified that alarm 1 is ringing.

Additional context
I am using firebase cloud messaging and handlers for notifications from that, but they're not firing when an alarm sounds, either (not that I'd expect them too - I'm just adding this in case there's some weird collision there)

[ApplySci]

NB the listener fires properly on ipad, AFAICT - it's specifically an android issue.

Because of the new Play Store restrictions, I've got this in my AndroidManifest.xml:

    <uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM"/>
    <uses-permission android:name="android.permission.USE_EXACT_ALARM" tools:node="remove"
        tools:ignore="ExactAlarm" />
    <uses-permission android:name="android.permission.USE_FULL_SCREEN_INTENT" tools:node="remove" />

[ApplySci]

In AlarmPlugin.alarmTriggerApi?.alarmRang(id.toLong()), in debugging, I get:

FlutterError: Unable to establish connection on channel: 'dev.flutter.pigeon.alarm.AlarmTriggerApi.alarmRang'.

from a debugging line I added to check the success of that line

[gdelataillade]

Hi @ApplySci

Sorry for the late reply. Do you still have the issue ?

@orkun1675 do you have an idea of what could be causing the issue ?

[ApplySci]

yes, @gdelataillade , it's still there

[orkun1675]

@ApplySci I'm happy to look into this. Can you share a minimum reproducible example? For instance, can modify the example app to get it to print the error message you mentioned above?

[ApplySci]

It works on iphone ok, it's an Android-specific problem.

Based on debugging lines I added to my local copy of the live main at commit 6f8157b at https://github.com/gdelataillade/alarm/blob/6f8157b6f4a72a58945da74440d9da8b524ffd1f/android/src/main/kotlin/com/gdelataillade/alarm/alarm/AlarmService.kt#L125:

        // Notify the plugin about the alarm ringing
        AlarmPlugin.alarmTriggerApi?.let { api ->
            Log.d("AlarmService", "Attempting to notify Flutter about alarm $id ringing")
            api.alarmRang(id.toLong()) { result ->
                if (result.isSuccess) {
                    Log.d("AlarmService", "Flutter was notified that alarm $id is ringing.")
                } else {
                    Log.e("AlarmService", "Failed to notify Flutter about alarm $id: ${result.exceptionOrNull()}")
                }
            }
        } ?: Log.e("AlarmService", "Cannot notify Flutter - AlarmTriggerApi is null")

Debug log;

D/AlarmService(20773): Attempting to notify Flutter about alarm 1 ringing

And that's it. It just failed silently, none of the other Log messages were issued on that call. So I kill that alarm.

But when the next alarm sounds, I get this:

D/AlarmService(20773): Attempting to notify Flutter about alarm 2 ringing
E/AlarmService(20773): Failed to notify Flutter about alarm 1: com.gdelataillade.alarm.generated.FlutterError: Unable to establish connection on channel: 'dev.flutter.pigeon.alarm.AlarmTriggerApi.alarmRang'.

Note that this was trying to notify about alarm 2, but the channel message is about alarm 1.

[ApplySci]

Claude.ai thinks it might be because my app is causing the Dart isolate to restart,a few seconds after launch, causing channel communication problems. I'm investigating that now.

[ApplySci]

ugh, ok, that was a pain, but I got there. The problem is a collision between Alarm and Firebase Cloud Messaging. When I retrieve my FCM token, it starts a new background isolate. Alarm, seeing this new engine, attaches to it, instead of the main engine. And this means that Alarm can no longer send messages to the app, so the listener fails. I've got a fix, which involves some non-trivial changes to AlarmPlugin.kt . I'll produce a diff shortly for testing.

[orkun1675]

Great fix!