在Parse(iOS SDK)中从列类型的数组中删除项

Question

我有表名"事件".在该表中,我有一个string类型的列.我正在努力解决如何从该列中仅删除一个元素的问题.考虑下面的图像,我想从"usersIncluded"列中删除所有出现的"iYYeR2a2rU",而不删除行.我用过了removeObject:(id) forKey:(NSString *)它并没有用.

这就是我试图实现它的方式:

  PFQuery *query = [PFQuery queryWithClassName:@"Events"];
    NSArray *eventObjects = [query findObjects];
    [query whereKey:@"usersIncluded" equalTo:[self.uniqeFriendList objectAtIndex:indexPath.row]];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error){
        for (int i = 0; i<objects.count; i++) {
            PFObject *event = [eventObjects objectAtIndex:i];
            [event removeObject:[self.uniqeFriendList objectAtIndex:indexPath.row] forKey:@"usersIncluded"];
        }
    }];
}

这self.uniqeFriendList是一个可变数组,包含我要从'usersIncluded'列中删除的ID.

提前致谢

Answer 1

我认为你正在使用正确的方法(removeObject:forKey:应该按照你想要的那样做),但我认为你正在使用来自错误数组的对象.您正在执行两次查询,并且在findObjectsInBackgroundWithBlock:您第一次调用它时使用数组...尝试这样做:

PFQuery *query = [PFQuery queryWithClassName:@"Events"];
[query whereKey:@"usersIncluded" equalTo:[self.uniqeFriendList objectAtIndex:indexPath.row]];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error){
    for (int i = 0; i <objects.count; i++) {
        PFObject *event = [objects objectAtIndex:i];    // note using 'objects', not 'eventObjects'
        [event removeObject:[self.uniqeFriendList objectAtIndex:indexPath.row] forKey:@"usersIncluded"];
    }

    [PFObject saveAll:objects];
}];

}