How to fetch all liked images (pointer) from current user?

Question

I have a Parse classes "Activity" and "Photo". How to fetch NSArray of PFObjects liked images from currentUser?

PFQuery *queryLikedPhoto = [PFQuery queryWithClassName:@"Activity"];
[queryLikedPhoto whereKey:@"type" equalTo:@"like"];
[queryLikedPhoto whereKey:@"fromUser" equalTo:[PFUser currentUser]];
[queryLikedPhoto includeKey:@"photo"];
[queryLikedPhoto findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        for (PFObject *object in objects) {
            PFObject *photoObject = [object objectForKey:@"photo"];
            [photoObject fetchIfNeededInBackgroundWithBlock:^(PFObject *photoObjects, NSError *error) {
                NSLog(@"photoObjects: %@", photoObjects);
            }];
        }
    }
}];

And it retrieve PFOjects with images, but how to save it to NSArray for further using?! (variants with NSMutableArray doesn't work):

PhotoObjects: <Photo: 0x166baf30, objectId: Q0H7XKYeCU, localId: (null)> { image = "<PFFile: 0x166ba810>"; thumbnail = "<PFFile: 0x166ba450>"; user = "<PFUser: 0x1668c6f0, objectId: qGYdDnAtbD, localId: (null)>"; username = "Tim"; } 2015-10-18 23:39:57.058 MyApp[5817:572564] photoObjects: <Photo: 0x166bdec0, objectId: eWGonc9YLz, localId: (null)> { image = "<PFFile: 0x166bd9e0>"; thumbnail = "<PFFile: 0x166bd6a0>"; user = "<PFUser: 0x1668c6f0, objectId: qGYdDnAtbD, localId: (null)>"; username = "Steve"; }

This query looks better Edit:

PFQuery *queryLikedPhoto = [PFQuery queryWithClassName:@"Activity"];
[queryLikedPhoto whereKey:@"type" equalTo:@"like"];
[queryLikedPhoto whereKey:@"fromUser" equalTo:[PFUser currentUser]];
[queryLikedPhoto whereKeyExists:@"photo"];
[queryLikedPhoto findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        self.likedPhotoObjects = [NSMutableArray array];
        if (objects.count >0) {
            for (PFObject *object in objects) {
                PFObject *photoObject = [object objectForKey:@"photo"];
                [self.likedPhotoObjects addObject:photoObject];
            }
        }
           [self.collectionView reloadData];
    }
}];

Answer 1

EXTRACT IMAGE FROM PFQUERY

You appear to be treating your " photo " PFFile object as a PFObject instead of a PFFile.

Insert the following code within your query block :

PFFile *imageFile = [object objectForKey:@"photo"];

[imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error)
{
    if (!error)
    {
        // SUCCESS.

        imageView.image = [UIImage imageWithData:data];                     
    }
    else
    {
        // ERROR.

        NSLog(@"%@", error);
    }
}];

---

SAVE SAID IMAGE

I would use an image cache Cocoa Pod [ ie. SAM CACHE ].

When I use SAM Cache saving an image file is as simple as :

[[SAMCache sharedCache] setImage:[UIImage imageWithData:data] forKey:imageKey];

wherein : imageKey refers to a unique NSString attached to the object within the data table [ ie. the ObjectId ].

---

RETRIEVE SAID IMAGE

To retrieve the image file in the future I then execute the following line of code :

UIImage *cacheImage = [[SAMCache sharedCache] imageForKey:imageKey];

---

CHECK WHETHER IMAGE IS IN CACHE

To check whether an image exists within the cache for the imageKey

UIImage *cacheImage = [[SAMCache sharedCache] imageForKey:imageKey];

if ( cacheImage )
{
    // Image exists within cache.
}
else
{
    // Image does not exist within cache.
}

---

ALTERNATIVES FOR CACHING

Parse.com also provides a cache feature referenced within their SDK.

Please refer to the following link for further info :

https://www.parse.com/docs/ios/guide#queries-caching-queries

---