Using pointers with Parse.com - ios

Question

I'm currently developing my first App. The App is a Basic messenger App based on Parse.com.
I want to create a PFQueryTableViewController where it will show the recent chats with other users.
Photo of other user, Name of other user and timestamp (similar to Facebook messanger "recent" tab).
the chats data is saved in a Parse Class named Room with the following columns:
objectid(string)
roomname(string)
User_1(pointer to _User)
User_2(pointer to _User)...
I can fill the table view easily with the string values (e.g the roomname) but I would like to get the users #"full name" as the Label of each cell.
this is my code (I get an empty TableView):
- (PFQuery *)queryForTable {
PFQuery *query = [PFQuery queryWithClassName:#"Room"];
[query includeKey:#"User_2"];
if (self.objects.count == 0) {
query.cachePolicy = kPFCachePolicyCacheThenNetwork;
}
[query orderByDescending:#"createdAt"];
return query;
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
object:(PFObject *)object
{
static NSString *cellIdentifier = #"Cell";
PFTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) {
cell = [[PFTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:cellIdentifier];
}
cell.textLabel.text = object[#"fullname"];
return cell;
}

Answer 1

When the pointer object is initially available it's just a stub, it doesn't actually contain any data. You need to call fetchAllIfNeededInBackground:block: on it (them, to keep things efficient) to populate the data.
Look at subclassing the table view controller and overriding - (void)objectsDidLoad:(NSError *)error to trigger the fetch on the new objects.
Note that you might just want to change your Room class to cache the user names (though if you do that you will need some cloud code to update the caches if the user name changes).

Answer 2

Ok, I solved it, hope this helps others.
This is the updated working code:
- (PFQuery *)queryForTable {
PFQuery *query = [PFQuery queryWithClassName:#"Room"];
[query includeKey:#"User_2"];
// If no objects are loaded in memory, we look to the cache first to fill the table
// and then subsequently do a query against the network.
if (self.objects.count == 0) {
query.cachePolicy = kPFCachePolicyCacheThenNetwork;
}
[query orderByDescending:#"createdAt"];
return query;
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
object:(PFObject *)object
{
static NSString *cellIdentifier = #"Cell";
PFTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) {
cell = [[PFTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:cellIdentifier];
}
PFObject *user = object[#"User_2"];
[user fetchIfNeededInBackgroundWithBlock:^(PFObject *user, NSError *error) {
//NSLog(#"%#", user);
cell.textLabel.text = user[#"fullname"];
}];
return cell;
}
#end