本地通知在iOS中不起作用

Question

I'm trying yo store my notifications in a database after scheduling them. For the life of me, I can't get the notification to show up in the iOS simulator. Any idea what's wrong?Here's the app delegate code for setting notifications. Basically, events are set to be weekly, and the descriptor string is of the form "Lecture on Monday from 5:04 AM to 6:09 AM". I then add the current date(without time) to the time to set the notification before storing in the database. The notification doesn't fire up, but if I show the stuff in the notifications database in a table view it looks like (null)(null)

    -(void)applicationDidBecomeActive:(UIApplication *)application
{
    NSArray *arrrayToSetNotifications= nil;
    arrrayToSetNotifications= self.getAlleventsToday;
    if (arrrayToSetNotifications!=nil)
    {


        for (Events *event in arrrayToSetNotifications)
        {

            NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
            [dateFormatter setDateFormat:@"dd.MM.yyyy HH:mm a"];

            [dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"GMT+5:30"]];

            NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc] init];
            [dateFormatter2 setDateFormat:@"dd.MM.yyyy"];
            [dateFormatter2 setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"GMT+5:30"]];

            NSDate *now=[NSDate date];
            NSString *todaysdate=[dateFormatter2 stringFromDate:now];


            NSDate *datefromstring = [[NSDate alloc] init];
            // voila!
            NSArray *words=[event.descriptorString componentsSeparatedByString:@" "];
            NSString *dateString=[NSString stringWithFormat:@"%@ %@ %@",todaysdate,[words objectAtIndex:4],[words objectAtIndex:5]];
            datefromstring=[dateFormatter dateFromString:dateString];

            UILocalNotification *notification=[[UILocalNotification alloc]init];
            notification.fireDate=datefromstring;
            notification.repeatInterval=NSWeekCalendarUnit;
            [application scheduleLocalNotification:notification];


            AppDelegate *appDelegate =
            [[UIApplication sharedApplication] delegate];

            NSManagedObjectContext *context =
            [appDelegate managedObjectContext];
            NSManagedObject *notification2;
            [notification2 setValue:datefromstring forKey:@"date"];
            [notification2 setValue:0 forKey:@"attendedValue"];
            [notification2 setValue:event forKey:@"event"];
            notification2 = [NSEntityDescription
                            insertNewObjectForEntityForName:@"Notifications"
                            inManagedObjectContext:context];
            NSError *error;
            [context save:&error];
        }
    }

}

Answer 1

At the very least, you need a lower case hh for the time field, rather than an upper case because you're parsing with a 12-hour time and an AM / PM . you use HH for 24 hour time parsing and display.

When you try to parse using both, it seems to get epically confused for the hour; eg

NSString *toParse = @"2014-01-20 08:00 AM";
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
[fmt setDateFormat:@"yyyy-MM-dd HH:mm a"];
NSDate *dateFromString = [fmt dateFromString:toParse];
NSLog(@"%@", dateFromString);
[fmt setDateFormat:@"yyyy-MM-dd hh:mm a"];
dateFromString = [fmt dateFromString:toParse];
NSLog(@"%@", dateFromString);

Your second problem is that you're not actually storing any useful information in the core data store. Your code starts trying to setValue on an uninitialized NSManagedObject *notification2 . This should be swapped around to:

NSManagedObject *notification2 = [NSEntityDescription
         insertNewObjectForEntityForName:@"Notifications"
         inManagedObjectContext:context];
[notification2 setValue:datefromstring forKey:@"date"];
[notification2 setValue:0 forKey:@"attendedValue"];
[notification2 setValue:event forKey:@"event"];

That way the data from parsing is stored in the created insertion object rather than being discarded.