My application gives user an option to schedule daily notifications on a specific time. I use AlarmManager to achieve this behavior.
On a click of a button I execute the following code:
val datetimeToAlarm = Calendar.getInstance(Locale.getDefault())
/*datetimeToAlarm.set(HOUR_OF_DAY, 21)
datetimeToAlarm.set(MINUTE, 0)
datetimeToAlarm.set(SECOND, 0)
datetimeToAlarm.set(MILLISECOND, 0)*/
NotificationHelper.createNotificationChannel(
requireContext(),
NotificationManagerCompat.IMPORTANCE_DEFAULT,
false,
weather,
"Daily weather notifications for ${weather.cityName}"
)
NotificationHelper.scheduleNotification(
requireContext(),
datetimeToAlarm,
weather
)
For testing purposes I do not set the exact time it must fire at just yet.
The two methods of NotificationHelper class that I use above:
fun createNotificationChannel(
context: Context,
importance: Int,
showBadge: Boolean,
data: Weather,
description: String
) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
// Format: $placeId-$cityName
val channelId = "${data.placeId}-${data.cityName}"
val channel = NotificationChannel(channelId, "Weather for ${data.cityName}", importance)
channel.description = description
channel.setShowBadge(showBadge)
val notificationManager = context.getSystemService(NotificationManager::class.java)
notificationManager.createNotificationChannel(channel)
Log.v("Notifications", "Created channel $channelId")
}
}
fun scheduleNotification(context: Context, timeOfNotification: Calendar, data: Weather) {
val intent = Intent(context, AlarmReceiver::class.java)
intent.putExtra(EXTRA_TITLE, "Weather for ${data.cityName}")
intent.putExtra(EXTRA_TEXT, "Temperature: ${data.daily[0].temperature.min.roundToInt()}°/${data.daily[0].temperature.max.roundToInt()}°")
intent.putExtra(EXTRA_ID, data.id)
intent.putExtra(EXTRA_PLACE_ID, data.placeId)
intent.putExtra(EXTRA_CITY_NAME, data.cityName)
val pending =
PendingIntent.getBroadcast(context, data.id, intent, PendingIntent.FLAG_UPDATE_CURRENT)
// Schedule notification
val manager = context.getSystemService(Context.ALARM_SERVICE) as AlarmManager
val repeatInterval: Long = 1000 * 60 * 15 // 15 minutes
manager.setRepeating(AlarmManager.RTC_WAKEUP, timeOfNotification.timeInMillis, repeatInterval, pending)
// start time is in AM/PM format
Log.v("Notifications", "Scheduled notification id ${data.id} with start at " +
"${SimpleDateFormat("yyyy-MM-dd hh:mm:ss", Locale.getDefault()).format(timeOfNotification.timeInMillis)} and interval " +
SimpleDateFormat("MM-dd hh:mm:ss", Locale.getDefault()).format(repeatInterval))
}
Again, for testing purposes I set repeating interval to 15 minutes just to see if it works.
In my BroadcastReciever's onReceive method I just call createNotification of my NotificationHelper class
override fun onReceive(context: Context, intent: Intent) {
// Deliver the notification.
Log.v("Notifications", "Receiver received call")
if (intent.extras == null) return
val title = intent.getStringExtra(NotificationHelper.EXTRA_TITLE)!!
val text = intent.getStringExtra(NotificationHelper.EXTRA_TEXT)!!
val id = intent.getIntExtra(NotificationHelper.EXTRA_ID, -1)
val placeId = intent.getStringExtra(NotificationHelper.EXTRA_PLACE_ID)
val cityName = intent.getStringExtra(NotificationHelper.EXTRA_CITY_NAME)
NotificationHelper.createNotification(
context,
title,
text,
"",
"$placeId-$cityName",
id
)
}
fun createNotification(
context: Context,
title: String,
message: String,
bigText: String,
channelId: String,
id: Int,
autoCancel: Boolean = true
) {
Log.v("Notifications", "Fired notification creation with following parameters: $title, $message, $channelId, $id")
val notificationBuilder = NotificationCompat.Builder(context, channelId).apply {
setSmallIcon(R.drawable.ic_launcher_foreground)
setContentTitle(title)
setContentText(message)
setStyle(NotificationCompat.BigTextStyle().bigText(bigText))
priority = NotificationCompat.PRIORITY_DEFAULT
setAutoCancel(autoCancel)
val intent = Intent(context, MainActivity::class.java)
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
val pendingIntent = PendingIntent.getActivity(context, 0, intent, 0)
setContentIntent(pendingIntent)
}
val notificationManager = NotificationManagerCompat.from(context)
notificationManager.notify(id, notificationBuilder.build())
}
And of course, my receiver is registered in the manifest:
<receiver
android:name=".utils.notifications.AlarmReceiver"
android:enabled="true"
android:exported="false"/>
When I launch my app on an emulator API 30 and click the button, I get the following logs:
2021-03-06 20:13:11.615 11229-11229/com.calamity.weather V/Notifications: Created channel location_place-Mountain View
2021-03-06 20:13:11.626 11229-11229/com.calamity.weather V/Notifications: Scheduled notification id 1 with start at 2021-03-06 08:13:11 and interval 01-01 03:15:00
2021-03-06 20:13:16.624 11229-11229/com.calamity.weather V/Notifications: Receiver received call
2021-03-06 20:13:16.624 11229-11229/com.calamity.weather V/Notifications: Fired notification creation with following parameters: Weather for Mountain View, Temperature: 9°/15°, location_place-Mountain View, 1
My notification is shown right away, and if I go and close my app, it will be delivered again after 15 minutes.
However, if I launch it on a real device (Xiaomi Redmi Note 9, MIUI Global 12.0.4, API 29), on a click of a button my logs are:
2021-03-06 20:16:50.945 19673-19673/com.calamity.weather V/Notifications: Created channel ChIJiQHsW0m3j4ARm69rRkrUF3w-Mountain View
2021-03-06 20:16:50.951 19673-19673/com.calamity.weather V/Notifications: Scheduled notification id 2 with start at 2021-03-06 08:16:50 and interval 01-01 03:15:00
As you can see, alarm is not fired even if my app is still in the foreground, not to mention if I swipe it out of recent apps list. So the questions are:
- Why doesn't it fire even with the app still running?
- How do I make it behave how it's supposed to and deliver my notifications even with closed app?
I did my research and found out that Chinese ROMs aggressively restrict Services and Jobs, but it seems like AlarmManager should work regardless.
