将用户添加到PFRelation

Question

我试图做一个“朋友”系统在我的应用程序，而当用户接受好友请求，我都将用户添加到这样一个关系：

var cUserRelation = PFUser.currentUser().relationForKey("friendsRelation") as PFRelation 
var senderRelation = sender.relationForKey("friendsRelation") as PFRelation 

cUserRelation.addObject(sender) 
senderRelation.addObject(PFUser.currentUser()) 

PFUser.currentUser.saveInBackground() 
sender.saveInBackground() 

但由于某种原因，它只会将发件人添加到当前用户的关系中。我该如何解决这个问题？谢谢:)

Answer 1

下面是从树屋的样本项目，可能会有所帮助：

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 

[self.tableView deselectRowAtIndexPath:indexPath animated:nil]; 


UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; 

// if the current relationKey doesn't exist, it will be create for us. 
PFRelation *friendsRelation = [self.currentUser relationForKey:@"friendsRelation"]; 
// adding users is easy. use addObject methoed then we can pass in the user that was tapped on as the parameter. To get that user, we have to get the indexPath just like we did in the 'cellForRowAtIndexPath' method 
PFUser *user = [self.allUsers objectAtIndex:indexPath.row]; 

if ([self isFriend:user]) 
{ 

    cell.accessoryType = UITableViewCellAccessoryNone; 
    // 2. remove from the array of friends // the only way we have to find a user in an array is to loop through and look for a matching objectid. 
    for (PFUser *friend in self.friends) 
    { 
     if ([friend.objectId isEqualToString:user.objectId]) 
     { 
      [self.friends removeObject:friend]; 
      break; 
     } 
    // 3. Remove from the backend 
     [friendsRelation removeObject:user]; 
     [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) { 
      NSLog(@"Error %@ %@", error, [error userInfo]); 
     }]; 
    } 
} 
    else 
{ 
    cell.accessoryType = UITableViewCellAccessoryCheckmark; 
    [self.friends addObject:user]; 
    for (PFUser *friend in self.friends) { 
     if ([friend.objectId isEqualToString:user.objectId]) { 
      [self.friends addObject:friend]; 
      break; 
     } 

     // and now we can use the user variable here as the parameter for addObject, which adds the user locally 
     [friendsRelation addObject:user]; 
     // but we also have to add the user on the backend 
     [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) { 
      if (error) { 
       NSLog(@"Error %@ %@", error, [error userInfo]); 
      } 
     }]; 


    } 
} 
}