iPhone - 数组计数的numberOfRowsInSection错误

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSMutableArray objectAtIndex:]: index 0 beyond bounds for empty array'

self.items

self.notification

NSDictionary *commentsDict = [NSDictionary dictionaryWithObject:self.notification.Comments forKey:@"Comments"];
NSDictionary *likesDict = [NSDictionary dictionaryWithObject:self.notification.Likes forKey:@"Likes"];
NSDictionary *friendsDict = [NSDictionary dictionaryWithObject:self.notification.Likes forKey:@"Friends"];

self.items = [NSMutableArray array];

[self.items addObject:commentsDict];
[self.items addObject:likesDict];
[self.items addObject:friendsDict];

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    NSDictionary *dictionary = [self.items objectAtIndex:section];
    NSArray *array = nil;

    if (section == 0) {
        array = [dictionary objectForKey:@"Comments"]; // 0 count
    } else if (section == 1) {
        array = [dictionary objectForKey:@"Likes"]; // 1 count or greater
    } else {
        array = [dictionary objectForKey:@"Friends"]; // 1 count or greater
    }

    return [array count];
}