在请求时不触发AlarmManager

Question

So I've made an app that's supposed to send a notification at 8:15 every Wednesday morning. I'm using an AlarmManager to send inexact repeating alarms from a calendar date to open a pending intent that sends a notification.

What's currently happening is the notification is being sent only if you first download the app. It did not go off this morning like it should have for myself or any of my users. I'm wondering if the AlarmManager is being scheduled for one week after that first notification fires (ie, a week after first downloading the app)?

Here is my manageNotifications method in MainActivity:

public void manageNotifications() {

    alarmManager = (AlarmManager) this.getSystemService(Context.ALARM_SERVICE);
    alarmIntent = new Intent(this, AlarmReceiver.class);
    pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);
    calendar = java.util.Calendar.getInstance();

    calendar.setTimeInMillis(System.currentTimeMillis());
    calendar.set(java.util.Calendar.DAY_OF_WEEK, java.util.Calendar.WEDNESDAY);
    calendar.set(java.util.Calendar.HOUR_OF_DAY, 8);
    calendar.set(java.util.Calendar.MINUTE, 15);

    /*
    sets alarm manager to go off at 8:15 in the morning every 7 days on Wednesday
     */
    alarmManager.setInexactRepeating(AlarmManager.RTC, calendar.getTimeInMillis(), 1000 * 60 * 60 * 24 * 7, pendingIntent);
}//end manageNotifications

Here is my AlarmReceiver that the pending intent calls:

public class AlarmReceiver extends BroadcastReceiver {

NotificationCompat.Builder notificationBuilder;
Intent notificationResultIntent;
ArrayList<Show> shows;
SharedPreferences spSpreadsheets, spNotifications;
final String showSpreadsheetURL = "https://docs.google.com/spreadsheets/d/1Ax2-gUY33i_pRHZIwR8AULy6-nbnAbM8Qm5-CGISevc/gviz/tq";

public void onReceive(Context context, Intent intent) {
    System.out.println("AlarmReceiver created");
    spNotifications = context.getSharedPreferences("notificationToggle", Context.MODE_PRIVATE);
    spSpreadsheets = context.getSharedPreferences("spreadsheets", Context.MODE_PRIVATE);

    if (spNotifications.getBoolean("notifications", false)) {
        int nextRegularShowIndex = 0, i = 0;

        shows = new ArrayList<>();

        try {
            if (spSpreadsheets.getString("showsSpreadsheet", "").equals(""))
                getShows(context);
            shows = processShowsJson(new JSONObject(spSpreadsheets.getString("showsSpreadsheet", "")));

            while (shows.get(i).getShowTime() != 0) {
            /*
            checks for first instance of a regular showtime
             */
                i++;
                nextRegularShowIndex = i;
            }
            checkForPastShows();
            notificationBuilder = new NotificationCompat.Builder(context)
                    .setSmallIcon(R.drawable.applogo)
                    .setContentTitle("Comedy Club of Jacksonville")
                    .setContentText(shows.get(nextRegularShowIndex).getComedian() + " headlines this weekend at the Comedy " +
                            "Club of Jacksonville.  Click to read more.")
                    .setDefaults(Notification.DEFAULT_ALL);
            notificationResultIntent = new Intent(context, ThisWeekendFromNotification.class).putParcelableArrayListExtra("shows", shows);

            TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
            stackBuilder.addParentStack(ThisWeekend.class);
            stackBuilder.addNextIntent(notificationResultIntent);
            PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
            notificationBuilder.setContentIntent(resultPendingIntent);
            notificationBuilder.setAutoCancel(true);
            NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
            mNotificationManager.notify(0, notificationBuilder.build());
            System.out.println("Notification built");

        } catch (Exception e) {
            e.printStackTrace();
        }//end onReceive
    }
}

And here is my BootReceiver class used to reset the alarm when a phone is restarted:

public class BootReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    if (intent.getAction().equals("android.intent.action.BOOT_COMPLETED")) {
        java.util.Calendar calendar = java.util.Calendar.getInstance();
        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent alarmIntent = new Intent(context, AlarmReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);

        calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.set(java.util.Calendar.DAY_OF_WEEK, java.util.Calendar.WEDNESDAY);
        calendar.set(java.util.Calendar.HOUR_OF_DAY, 8);
        calendar.set(java.util.Calendar.MINUTE, 15);

    /*
    sets alarm manager to go off at 8:15 in the morning every 7 days on Wednesday
     */
        alarmManager.setInexactRepeating(AlarmManager.RTC, calendar.getTimeInMillis(), 1000 * 60 * 60 * 24 * 7, pendingIntent);
    }
}

}

Answer 1

First, you are using setInexactRepeating() . Unless your minSdkVersion is 19 or higher, you cannot use setInexactRepeating() with an arbitrary period.

Second, setInexactRepeating() is inexact. Your alarm will not go off at 8:15am on a Wednesday. It will go off sometime. Quoting the JavaDocs :

Your alarm's first trigger will not be before the requested time, but it might not occur for almost a full interval after that time.

Third, as Squonk notes in the comment, you are using RTC as the alarm type. Your alarm will be further delayed, until the device wakes up for some other reason.

If your targetSdkVersion is below 19, you can use setRepeating() for an exact repeating alarm. Otherwise, use set() (pre-API Level 19) and setExact() (API Level 19+) to schedule your alarm, and schedule the next alarm as part of the work done when the alarm goes off. Also, use RTC_WAKEUP , if you want to wake the device out of sleep mode to do your work.