How to show Notifications from AlarmReceiver even when device has been restarted in jetpack compose - android-jetpack-compose

Question

I have an application in Jetpack Compose that notifies scheduled alarms set by the user and it works well; however, when the device is restarted, the alarm does not sound. For example, if the user sets the alarm to go off in two minutes, this works; however, if the device is restarted before the alarm is triggered, the alarm will not sound.
I have this method to save an alarm:
#RequiresApi(Build.VERSION_CODES.M)
#Composable
fun AddPage(navController: NavController, vm: TaskViewModel = viewModel()) {
val scope= rememberCoroutineScope()
val calendar=Calendar.getInstance().apply {
timeInMillis=System.currentTimeMillis()
}
val title = remember {
mutableStateOf("")
}
val description = remember {
mutableStateOf("")
}
val year= remember {
mutableStateOf(calendar.get(Calendar.YEAR))
}
val month= remember {
mutableStateOf(calendar.get(Calendar.MONTH)+1)
}
val day= remember {
mutableStateOf(calendar.get(Calendar.DAY_OF_MONTH))
}
val hour= remember {
mutableStateOf(calendar.get(Calendar.HOUR_OF_DAY))
}
val minutes= remember {
mutableStateOf(calendar.get(Calendar.MINUTE))
}
val showPopup= remember {
mutableStateOf(false)
}
val msg= remember {
mutableStateOf("")
}
val icon= remember {
mutableStateOf(Icons.Filled.Done)
}
if (showPopup.value){
PopupMessagePage(msg.value,400.dp,500.dp,showPopup.value,{
showPopup.value=false
},
icon.value)
}
val context = LocalContext.current
Column(
modifier = Modifier
.fillMaxSize()
.padding(top = 30.dp),
horizontalAlignment = Alignment.CenterHorizontally
) {
Text(
text = "Agregar Tarea",
style = NoteTheme.typography.h1
)
RowOfThis(title, "Título", true)
RowOfThis(description, "Descripción", false)
Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
DatePick(context = context, year = year, month = month, day = day)
}
Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
TimePick(context = context, hours = hour, minutes = minutes)
}
Button(
onClick = {
if (title.value.isNullOrBlank() || description.value.isNullOrBlank()
) {
msg.value="Por favor ingrese todos los datos"
icon.value=Icons.Filled.Warning
showPopup.value=true
return#Button
}
scope.launch {
calendar.apply {
set(Calendar.YEAR,year.value)
set(Calendar.MONTH,(month.value-1))
set(Calendar.DAY_OF_MONTH,day.value)
set(Calendar.HOUR_OF_DAY,hour.value)
set(Calendar.MINUTE,minutes.value)
}
val shuff=(1..99999).shuffled().first()
vm.task.value.title = title.value
vm.task.value.description = description.value
vm.task.value.date = "${day.value}/${month.value}/${year.value}"
vm.task.value.time = calendar.timeInMillis
vm.task.value.dateCreated= getDateToday()
vm.task.value.shuff= shuff
vm.createTask(context, vm.task.value)
Log.e("tmepickerreceived","date and time :${year.value}/${month.value}/${day.value} : ${hour.value}:${minutes.value}")
val alarmMgr= context.getSystemService(Context.ALARM_SERVICE) as AlarmManager
val intent= Intent(context,AlarmReceiver::class.java)
intent.action="alarma"
intent.putExtra("ALARMA_ID_STRING","$shuff")
intent.putExtra("ALARMA_DESCRIPTION_STRING","${description.value}")
val pending=
PendingIntent.getBroadcast(context,shuff,intent, PendingIntent.FLAG_IMMUTABLE)
Log.e("time final","compare ${System.currentTimeMillis()}" +
" mytime: ${calendar.timeInMillis} " +
"hour: ${calendar.get(Calendar.HOUR_OF_DAY)} " +
"minute: ${calendar.get(Calendar.MINUTE)} " +
"year: ${calendar.get(Calendar.YEAR)} " +
"month: ${calendar.get(Calendar.MONTH)+1} " +
"day: ${calendar.get(Calendar.DAY_OF_MONTH)}")
alarmMgr?.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP,calendar.timeInMillis,pending)
msg.value="Recordatorio activado"
icon.value=Icons.Filled.Done
showPopup.value=true
vm.resetTask()
}
},
colors = ButtonDefaults.buttonColors(backgroundColor = Color.Blue)
) {
Text(text = "Guardar", color = Color.White, style = NoteTheme.typography.subtitle)
}
}
}
and i have this alarm receiver:
class AlarmReceiver: BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
Log.d("alarm","************************received")
if (intent?.action == "alarma") {
val number = intent?.getStringExtra("ALARMA_ID_STRING")
val description=intent?.getStringExtra("ALARMA_DESCRIPTION_STRING")
val mp= MediaPlayer.create(context,R.raw.alarma)
mp.start()
if (context != null) {
if (number != null) {
val pendingResult: PendingResult = goAsync()
val asyncTask = Task(pendingResult,context,number.toInt())
asyncTask.execute()
showNotification(context,number.toInt(),"Recordatorio: ${number.toInt()}","$description")
}
}
}
}
private class Task(
private val pendingResult: PendingResult,
private val context: Context,
private val number:Int
) : AsyncTask<String, Int, String>() {
override fun doInBackground(vararg params: String?): String {
if (context != null) {
TaskDatabase.getDatabase(context).taskDao().deleteAfterAlarm(number)
}
return toString().also { log ->
Log.d("BACKGROUND", log)
}
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
// Must call finish() so the BroadcastReceiver can be recycled.
pendingResult.finish()
}
}
private fun showNotification(context: Context,idN:Int,title:String,text:String){
try{
val manager=context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
val id= UUID.randomUUID().toString()
if (Build.VERSION.SDK_INT>= Build.VERSION_CODES.O){
val channel= NotificationChannel(id,
UUID.randomUUID().toString(), NotificationManager.IMPORTANCE_HIGH)
manager.createNotificationChannel(channel)
}
val fullScreenIntent = Intent(context, MainActivity::class.java)
val fullScreenPendingIntent = PendingIntent.getActivity(context, 0,
fullScreenIntent, PendingIntent.FLAG_IMMUTABLE)
var builder= NotificationCompat.Builder(context,id)
.setContentTitle(title)
.setContentText(text)
.setSmallIcon(R.drawable.ic_launcher_foreground)
.setFullScreenIntent(fullScreenPendingIntent,true)
manager.notify(idN,builder.build())
}catch (exc:Exception){
Toast.makeText(context,exc.toString(),Toast.LENGTH_LONG).show()
}
}
}
that methods works fine but if device is restarted the alarm does not work i have this in manifest too:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" />
<uses-permission android:name="android.permission.USE_FULL_SCREEN_INTENT" />
<application
android:allowBackup="true"
android:dataExtractionRules="#xml/data_extraction_rules"
android:fullBackupContent="#xml/backup_rules"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.NotePadReminder"
tools:targetApi="31">
<activity
android:name=".MainActivity"
android:exported="true"
android:label="#string/app_name"
android:theme="#style/Theme.NotePadReminder">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name="android.app.lib_name"
android:value="" />
</activity>
<receiver android:name="com.mobile.notepadreminder.AlarmReceiver"
android:enabled="true"
android:permission="android.permission.RECEIVE_BOOT_COMPLETED"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
</intent-filter>
</receiver>
</application>
</manifest>