Not able to delete a reminder from Calendar in Android

Question

I have added a calendar event programatically using the caledarcontract api and obtained a eventId. Similarly i added a reminder for this event and saved the reminderId too. Now i dont want a reminder for this event(or i would like to turn off the reminder), so i am trying to delete the reminder using the reminderId but i am not able to delete. I tried to delete the reminder using the eventId too but its not working.

public int AddEventToCalendar(String calendarId, Entity entity) {
    // TODO Auto-generated method stub
    ContentValues event = new ContentValues();
    event.put("calendar_id", calendarId);
    event.put("title", entity.description);
    event.put("dtstart", System.currentTimeMillis());
    event.put("dtend", System.currentTimeMillis() + 3600*1000);
    event.put("allDay", 0);
    //status: 0~ tentative; 1~ confirmed; 2~ canceled
    event.put("eventStatus", 1);
    //0~ default; 1~ confidential; 2~ private; 3~ public
    event.put("visibility", 0);
    //0~ opaque, no timing conflict is allowed; 1~ transparency, allow overlap of scheduling
    event.put("transparency", 0);
    //0~ false; 1~ true
    event.put("hasAlarm", 1);
    Uri add_eventUri;
    if (Build.VERSION.SDK_INT >= 8) {
        add_eventUri = Uri.parse("content://com.android.calendar/events");
    } else {
        add_eventUri = Uri.parse("content://calendar/events");
    }
    Uri l_uri = context.getContentResolver().insert(add_eventUri, event);
    if(l_uri != null)
    {
        long eventID = Long.parseLong(l_uri.getLastPathSegment());
        return (int) eventID;
    }
    else
        return 0;
}

public int AddReminderOnEvent(Entity entity)
{
    if(entity.eventId != 0)
    {
        ContentValues reminderValues = new ContentValues();
        reminderValues.put("event_id", entity.eventId);
        reminderValues.put("method", 1);// will alert the user with a reminder notification
        reminderValues.put("minutes", 0);// number of minutes before the start time of the event to fire a reminder
        Uri reminder_eventUri;
        if (Build.VERSION.SDK_INT >= 8) {
            reminder_eventUri = Uri.parse("content://com.android.calendar/reminders");
        } else {
            reminder_eventUri = Uri.parse("content://calendar/reminders");
        }
        Uri r_uri = context.getContentResolver().insert(reminder_eventUri, reminderValues); 
        if(r_uri != null)
        {
            long reminderID = Long.parseLong(r_uri.getLastPathSegment());
            return (int) reminderID;
//          Toast.makeText(getApplicationContext(), "Event Created Successfully", Toast.LENGTH_LONG).show();
        }
        else
            return 0;
    }
    else
    {
        return 0;
    }
}

    public boolean DeleteReminderOnTask(int eventId, int reminderId) {
    // TODO Auto-generated method stub

    Uri delete_reminderUri;
    if (Build.VERSION.SDK_INT >= 8) {
        delete_reminderUri = Uri.parse("content://com.android.calendar/reminders");
    } else {
        delete_reminderUri = Uri.parse("content://calendar/reminders");
    }
    delete_reminderUri = ContentUris.withAppendedId(delete_reminderUri, reminderId);
    int rows = context.getContentResolver().delete(delete_reminderUri,null , null);

    if(rows > 0)
        return true;
    else
        return false;

}

After executing this code everytime the rows returns 0 meaning that no rows have been altered. And the reminder comes up exactly at the appropriate time. How to delete the reminder from the calendar without deleting the event?

Answer 1

I'm not sure which SDK version you're running against when failing, but this code (which is essentially the same as yours, less the version check) works for me:

Uri reminderUri = ContentUris.withAppendedId(
    CalendarContract.Reminders.CONTENT_URI, reminderId);
int rows = contentResolver.delete(reminderUri, null, null);

I got reminderId by querying the event's reminders:

    String[] projection = new String[] {
            CalendarContract.Reminders._ID,
            CalendarContract.Reminders.METHOD,
            CalendarContract.Reminders.MINUTES
    };

    Cursor cursor = CalendarContract.Reminders.query(
        contentResolver, eventId, projection);
    while (cursor.moveToNext()) {
        long reminderId = cursor.getLong(0);
        int method = cursor.getInt(1);
        int minutes = cursor.getInt(2);

        // etc.

    }
    cursor.close();

Answer 2

This might not be the only or best way, but all I could figure out was how to remove all reminders for an event. I don't know of a way to remove just one reminder.

//What we want to update
ContentValues values = new ContentValues();
values.put(Events.HAS_ALARM, 0);

//We're setting the event to have no alarms
int result = getContentResolver().update(
    Events.CONTENT_URI,
    values,
    Events._ID + " = ?",
    new String[]{"44"}
);

Unfortunately, this removes all reminders, but I'm not sure multiple reminders are really supported by Android 14+ or most calendar providers (e.g. Exchange). The calendar app in ICS only allows adding one reminder (despite saying "Add Reminders").

And if i use another application such as Business Calendar to add multiple reminders, when I check in Exchange, it only shows ones reminder. It does show multiple reminders in the calendar app but only on that device, not on other devices, so multiple reminders seem to be local only.