IssueTracker

I'm trying to create my own alarm app because I accidentally disable the alarm when it goes off in my sleep. But when I tried to create the most crucial part of the alarm app, I couldn't get it to work. I posted my question on stackoverflow and reddit and nobody has an answer how to show an Activity when the alarmManager triggers. The only option someone suggested was to lower the target sdk, but I'd rather have the newest target sdk and upload it to the Play Store. I also looked into the code for the Clock app (unfortunately couldn't find the one used for WearOS, so this is code for the phone).

For starters, I asked for the notification permission, so notifications can be shown. I also checked alarmManager.canScheduleExactAlarms(), but I think this is always accepted, at least I never got to see a screen for it.

The code I'm using to set an alarm is this:

        context.alarmManager.setAlarmClock(
            AlarmManager.AlarmClockInfo(
                millis,
                PendingIntent.getActivity(context, 0, Intent(context, MainActivity::class.java), PendingIntent.FLAG_IMMUTABLE)
            ),
            PendingIntent.getBroadcast(context, 0, Intent(context, AlarmBroadcastReceiver::class.java), PendingIntent.FLAG_IMMUTABLE)
        )

AlarmBroadcastReceiver:

class AlarmBroadcastReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        context.startForegroundService(Intent(context, AlarmService::class.java))
    }
}

AlarmService:

class AlarmService : Service() {
    private fun customStartForeground() {
        val notification = updateNotification()
        if(sdk14OrNewer()) {
            startForeground(NotificationUtils.alarmNotificationId, notification, ServiceInfo.FOREGROUND_SERVICE_TYPE_SPECIAL_USE)
        } else {
            startForeground(NotificationUtils.alarmNotificationId, notification)
        }
    }

    private fun customStopForeground(removeNotification: Boolean = false) {
        //Always call startForeground before calling stopForeground (prevents crashes)
        customStartForeground()
        stopForeground(if(removeNotification) STOP_FOREGROUND_REMOVE else STOP_FOREGROUND_DETACH)
    }

    private fun updateNotification(): Notification {
        val intentStartVisualActivity = Intent(this, AlarmActivity::class.java)
        intentStartVisualActivity.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TOP
        val pendingIntent = PendingIntent.getActivity(this, 0, intentStartVisualActivity, PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT)

        val notificationBuilder = NotificationCompat.Builder(this, NotificationUtils.alarmNotificatonChannelId)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle("Alarm")
            .setContentText("Your alarm is going off")
            .setCategory(NotificationCompat.CATEGORY_ALARM)
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
            .setPriority(NotificationCompat.PRIORITY_MAX)
            .setFullScreenIntent(pendingIntent, true)

        val notification = notificationBuilder.build()

        val notificationManager = NotificationManagerCompat.from(this)
        notificationManager.notify(NotificationUtils.alarmNotificationId, notification)

        return notification
    }

    private fun stopAll() {
        customStopForeground(true)
        stopSelf()
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        customStartForeground()
        return START_NOT_STICKY
    }
    
    override fun onBind(intent: Intent?): IBinder? {
        return null
    }
}

This is the code I tried which includes .setFullScreenIntent(pendingIntent, true) on the notification, because this seemed to me the way to show the alarm screen (the Clock app also uses this). But couldn't get it to work. It shows the notification and I can get logging showing the Service is working, but no Activity is shown.

So after that I tried to pass a PendingIntent.getActivity like this:

        val alarmActivity = Intent(context, AlarmActivity::class.java).also {
            it.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TOP
        }
        context.alarmManager.setAlarmClock(
            AlarmManager.AlarmClockInfo(
                millis,
                PendingIntent.getActivity(context, 0, Intent(context, MainActivity::class.java), PendingIntent.FLAG_IMMUTABLE)
            ),
            PendingIntent.getActivity(context, 0, alarmActivity, PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT)
        )

This only works when the app is in the foreground. But when you are sleeping, the app won't be in the foreground (screen will most likely be off).

I also tried to just start the Activity from the AlarmBroadcastReceiver, because I didn't know what else to try, but that of course doesn't work.

Sorry for the long post. But it seems to me that there is no way to open an Activity after the AlarmManager triggers.