我的 alarmManager 代码是否能够发送广播？

Question

I'm trying to create an alarm Manager that sends notification every 24 hours at specific time consulted other Stackoverflow code. I tried this code below but onReceive() never gets executed. What i'm doing wrong?

private var HOUR_TO_SHOW_PUSH = 21
private var MINUTE_TO_SHOW_PUSH = 0
private val REQUEST_CODE = 100
private lateinit var alarmManager: AlarmManager
private lateinit var pendingIntent: PendingIntent

class MainActivity : AppCompatActivity() {
...
        alarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager
        val intent = Intent(this, AlertReceiver::class.java)
        pendingIntent = PendingIntent.getBroadcast(this, REQUEST_CODE, intent, PendingIntent.FLAG_UPDATE_CURRENT)
        val calendar = GregorianCalendar.getInstance().apply {
            if (get(Calendar.HOUR_OF_DAY) >= HOUR_TO_SHOW_PUSH) {
                add(Calendar.DAY_OF_MONTH, 1)
            }
            set(Calendar.HOUR_OF_DAY, HOUR_TO_SHOW_PUSH)
            set(Calendar.MINUTE, 0)
            set(Calendar.SECOND, 0)
            set(Calendar.MILLISECOND, 0)
        }
        alarmManager.setRepeating(
            AlarmManager.RTC_WAKEUP,
            calendar.timeInMillis,
            AlarmManager.INTERVAL_DAY,
            pendingIntent
        )

AlertReceiver

class AlertReceiver: BroadcastReceiver() {

    override fun onReceive(context: Context?, intent: Intent?) {
       
        override fun onReceive(context: Context?, intent: Intent?) {
        Toast.makeText(context, "Alarm", Toast.LENGTH_LONG).show()
        println("Alarm")
        Log.e("Alarm","Alarm Triggered")
    }

Manifest

<receiver
  android:name=".AlertReceiver"
  android:enabled="true"
  android:exported="true">
    <intent-filter>
       <action android:name="android.intent.action.BOOT_COMPLETED" />
       <action android:name="android.intent.action.LOCKED_BOOT_COMPLETED" />
       <action android:name="MyBroadcastReceiverAction"/>
   </intent-filter
</receiver>

Answer 1

Normally you would register your receiver in the AndroidManifest like this:

<receiver android:name=".MyBroadcastReceiver"  android:exported="true">
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED"/>
        <action android:name="android.intent.action.INPUT_METHOD_CHANGED" />
    </intent-filter>
</receiver>

https://developer.android.com/guide/components/broadcasts

Answer 2

it depends on the battery optimization applied to the app by the device, it varies from a device manufacturer to other
Normally you will find it in Settings > Apps > "your app name" > Battery Saver Set it to No Restrictions