在数据库中为重复事件建模，并使用UILocalNotification触发事件

Question

I'm not sure how this would work, but what I'd like is something similar to Apple's alarm clock that comes with the iPhone. It basically just lets you pick a time of an alarm, name the alarm, and then you can choose how often you want it to repeat (Sunday - Saturday). Based on what you choose, the alarm fires once, or at a repeated interval.

In my Core Data model, I wasn't sure how to model that. If I were thinking in terms of just plain old objects, I would think I would have some alarm object, and one of its properties would be an array. In that array I could have the day values of Sunday-Sautrday. Then when a new alarm object is created, I would schedule a UILocalNotification for the time selected, and the days chosen. To model that in terms of database objects, I'm not sure what I'm supposed to do. I was thinking something like:

Alarm - (name/string) Day - (Sunday - Saturday/represented by integers 0-6, 1 to many relationship from Alarm to Day)

Assuming that is ok in the database, then I'm not sure how I should go about scheduling the UILocalNotifications since I thought you could only have 64 per app. I'm thinking that I could have some mechanism to schedule the first 64 alarms possible, then when the app is opened, it would just reschedule the next upcoming 64 events. Is that how I would do that? Thanks.

Answer 1

Using 2 entities is overkill. I would just have the Alarm entity and have a single integer attribute on it to hold the alarm days. Outside of the entity, I would have an enumeration which defines how the alarm days number is interpreted. Something like:

typedef AlarmDays {
    Monday           = 0,
    Tuesday          = 1 << 0,
    Wednesday        = 1 << 1,
    Thursday         = 1 << 2,
    Friday           = 1 << 3,
    Saturday         = 1 << 4,
    Sunday           = 1 << 5
} AlarmDays;

Then you can test which days it should be on using:

if (alarm.alarmDays & Monday) {
    // the alarm should fire on mondays
}

And you can use the features of UILocalNotification , such as repeatInterval so you don't need to explicitly add gazillions of notifications to the system.