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];
    }
}];

@lightice11 I've tried to retrieve and write to nsmutablearray but always get null when read, is there any solution how to save for further using?! — vbondarenko3d, Oct 18 '15 at 22:30

score 0 · Answer 1 · answered Oct 18 '15 at 22:48

0

Judging from the print out you pasted in, the query is working correctly. Look at the guide on how PFFiles are handled. All you have done so far is to fetch pointers to the files, so now you need to download the file itself. (It's all in the guide)

answered Oct 18 '15 at 22:48

hhanesand

990
11
28

score 0 · Accepted Answer · answered Oct 19 '15 at 03:17

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

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

2 Answers2