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从Parse.com(iOS应用程序)的数据库中删除项目

delete-row relationship parse-platform ios

kAiN · 技术社区 · 11 年前

我正在为iOS应用程序8使用Parse.com。。。在解析数据库中,我创建了一个名为“Relationships”的新类,我想做的是给我的应用程序的用户添加前缀,以便向另一个用户发送好友请求。我没有使用PFRelation,因为我需要朋友请求不是自动的,而是被用户接受。

简而言之,用户发送请求richeista of friendship,这将保持在状态为“Waiting”的类“Relationship”中,直到用户不接受该请求。

现在我可以做我能做的一切:

用于注册这两个的用户指针(接收者和转发者的好友请求)
插入请求状态“待定”

我的问题是,如果我的用户不想要更多的“发送请求无法”删除。。

我尝试使用[“PFObject的名称”deleteInBackground],但我无法删除任何内容。。。

你能帮我弄清楚如何从数据库中删除新创建的数据进行解析吗?

#pragma mark ADD FRIENDS
-(void)addFriendUserButtonPressed:(UITableViewCell *)customCell  {


    NSIndexPath *indexPath = [self.tableViewFindUser indexPathForCell:customCell];

    PFObject *richiesta = [PFObject objectWithClassName:@"Relation"];

    if (!isFiltered) {

        PFUser *userFiltered = [self.userArray objectAtIndex:indexPath.row];

        if (![self Is_InAttesa:userFiltered]) {


            [richiesta setObject:userFiltered forKey:@"To_User"];
            [richiesta setObject:[PFUser currentUser] forKey:@"From_User"];
            [richiesta setObject:@"Pending" forKey:@"STATUS"];
            [richiesta saveInBackground];



        } else {


           //[richiesta removeObject:[PFUser currentUser] forKey:@"From_User"];
            //[richiesta setObject:userFiltered  forKey:@"STATUS"];
            //[richiesta saveInBackground];
        }



    }

    else {

        PFUser *userNotFiltered = [self.userFiltrati objectAtIndex:indexPath.row];


        [richiesta setObject:userNotFiltered forKey:@"To_User"];
        [richiesta setObject:[PFUser currentUser] forKey:@"From_User"];
        [richiesta setObject:@"Pending" forKey:@"STATUS"];
        [richiesta saveInBackground];

    }


}

这是我创建的布尔方法,用于识别(通过查询)用户是否存在于待定好友请求列表中

-(BOOL)Is_InAttesa:(PFUser *)user_inattesa {
    for (PFUser *userInAttesa in amiciInAttesaMutableArray) {
        if ([[[userInAttesa objectForKey:@"To_User"]objectId] isEqualToString:user_inattesa.objectId]) {
            return YES;
        }
    }
    return NO;
}

enter image description here

2 回复 | 直到 11 年前

nikhil84 11 年前

这里有一个从解析中删除对象的方法。

-(void)deleteButton {

  //Query or retrieving data from dB which you want to delete.
  PFQuery *query = [PFQuery queryWithClassName:@"YOUR_CLASS"];

  //This string in below case takes name from textfield that user wants to delete. For your case you could modify it as per your need.
  NSString *receiver_idStr =@"Id";
  NSString *sender_idStr =@"Id";

  // below two queries will work as like SELECT * FROM someTable WHERE senderId = 'id' AND receiverId = 'id'
  [query whereKey:@"request_sender_id" containsString:sender_idStr];
  [query whereKey:@"request_receiver_id" containsString:receiver_idStr];

  [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {  //Query fired in background to search in parse for this object with condition provided.

    if (!error) {
        NSLog(@"Successfully retrieved: %@", objects);

        //Now as you got object then you will type cast object from NSArray to PFObject and perform deleteInBackground method on them.

        //Also update that UI part ,i.e., remove the request object from UI.
    }
    else {
        NSLog(@"Error: %@", [error localizedDescription]);
    }
  }];
}

因此,这种方法将能够从解析中删除请求对象。此外,当发送请求的用户取消请求时,您也可以搜索该请求对象,并在接收请求的用户的其他位置执行同样的操作,您可以推送通知以从其UI中删除该请求。

若用户收到请求,那个么只需找到请求对象并删除,然后更新发送方和接收方的UI即可。

kAiN 11 年前

-(void)addFriendUserButtonPressed:(UITableViewCell *)customCell  {


    NSIndexPath *indexPath = [self.tableViewFindUser indexPathForCell:customCell];
    PFObject *richiesta = [PFObject objectWithClassName:NPFriendClass];
    if (!isFiltered) {

        PFUser *userFiltered = [self.userArray objectAtIndex:indexPath.row];

        if (![self Is_InAttesa:userFiltered]) {




            [richiesta setObject:userFiltered forKey:NPFriend_AUser];
            [richiesta setObject:userFiltered.objectId forKey:@"OBJECT_USER_ID"];
            [richiesta setObject:userFiltered.username forKey:@"Username"];
            [richiesta setObject:[PFUser currentUser] forKey:NPFriend_DaUser];
            [richiesta setObject:@"Richiesta In Attesa" forKey:NPFriendRequestStatus];
            [richiesta saveInBackground];



        } else {


            PFQuery *query = [PFQuery queryWithClassName:NPFriendClass];
            [query whereKey:NPFriend_DaUser equalTo:[PFUser currentUser]];
            [query whereKey:NPFriendRequestStatus equalTo:@"Richiesta In Attesa"];
            [query whereKey:@"OBJECT_USER_ID" equalTo:userFiltered.objectId];
            [query includeKey:NPFriend_AUser];
            [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {

                if(!error) {
                    for (PFObject *object in objects) {
                        NSLog(@"Successfully retrieved: %@", object);
                        [object deleteInBackground];
                    }
                }

                else {
                    NSLog(@"Error: %@", [error localizedDescription]);
                }
            }];




                   }
    }

    else {

        PFUser *userNotFiltered = [self.userFiltrati objectAtIndex:indexPath.row];


        [richiesta setObject:userNotFiltered forKey:NPFriend_AUser];
        [richiesta setObject:[PFUser currentUser] forKey:NPFriend_DaUser];
        [richiesta setObject:@"Richiesta In Attesa" forKey:NPFriendRequestStatus];
        [richiesta saveInBackground];

    }

}

您好,Walle再次感谢您的帮助,您非常友好和乐于助人。。。

我用这种方式修复了它,它似乎奏效了。。。

唯一的问题是它没有立即更新数据,因此用户无法确定您是否发送了请求。仅当表视图刷新表视图或更改视图控制器时,才会更新表视图。。

当用户发送好友请求时,我尝试再次重做查询,但数据重叠,并减慢了应用程序的速度。。。如何在不调用查询的情况下每分钟刷新一次数据?

选择按钮或不选择淀粉的想法会好吗?我在尝试,但可能出了问题,因为我无法让它发挥作用