Downloading images from Parse iOS

Question

I\'m writing an application that allows the users to take and store images on Parse. Thus far I\'ve managed to accomplish saving the image array to Parse by using the follo

Answer 1

In the .h file of your collection view you need to have something like below. Note that the one I built you could like an image and then sort liked images using a segment controller.

#import 
#import "UICollectionCell.h"
#import 

@interface ParseViewController : UIViewController {

    NSArray *imageFilesArray;
    NSMutableArray *imagesArray;
}

@property (weak, nonatomic) IBOutlet UICollectionView *imagesCollection;
- (IBAction)segmentSelected:(id)sender;
@property (weak, nonatomic) IBOutlet UISegmentedControl *segmentedController;



@end

Then in the .m file of your collection view

    @interface ParseViewController ()

@end

@implementation ParseViewController

@synthesize imagesCollection;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    [self queryParseMethod];

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

// code to add the number of images etc as per table view

-(void) queryParseMethod {
    NSLog(@"start query");
    PFQuery *query = [PFQuery queryWithClassName:@"collectionView"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            imageFilesArray = [[NSArray alloc] initWithArray:objects];
            NSLog(@"%@", imageFilesArray);
            [imagesCollection reloadData];
        }
    }];

}

#pragma mark - UICollectionView data source

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    // number of sections
    return 1;
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    // number of items
    return [imageFilesArray count];

}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    // the custom cell we named for the reusable identifier
    static NSString *cellIdentifier = @"imageCell";
    UICollectionCell *cell = (UICollectionCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

    PFObject *imageObject = [imageFilesArray objectAtIndex:indexPath.row];
    PFFile *imageFile = [imageObject objectForKey:@"imageFile"];

    // show loading spinner
    [cell.loadingSpinner startAnimating];
    cell.loadingSpinner.hidden = NO;

    [imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
        if (!error) {
            NSLog(@"%@", data);
            cell.parseImage.image = [UIImage imageWithData:data];
            [cell.loadingSpinner stopAnimating];
            cell.loadingSpinner.hidden = YES;

        }
    }];

    return cell;

}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    [self likeImage:[imageFilesArray objectAtIndex:indexPath.row]];
}

-(void) likeImage:(PFObject *)object {

    [object addUniqueObject:[PFUser currentUser].objectId forKey:@"favorites"];

    [object saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (!error) {
            NSLog(@"liked picture!");
            [self likedSuccess];
        }
        else {
            [self likedFail];
        }
    }];
}

-(void) likedSuccess {
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Success" message:@"You have succesfully liked the image" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
    [alert show];
}

-(void) likedFail {
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Unsuccesfull" message:@"You have been unable to like the image" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
    [alert show];
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

- (IBAction)segmentSelected:(id)sender {
    if (_segmentedController.selectedSegmentIndex == 0) {
        [self queryParseMethod];
    }
    if (_segmentedController.selectedSegmentIndex == 1) {
        [self retrieveLikedImages];
    }
}

-(void) retrieveLikedImages {
    PFQuery *getFavorites = [PFQuery queryWithClassName:@"collectionView"];
    [getFavorites whereKey:@"favorites" equalTo:[PFUser currentUser].objectId];

    [getFavorites findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            imageFilesArray = [[NSArray alloc] initWithArray:objects];
            [imagesCollection reloadData];
        }
    }];
}



@end

Hope this is of some help to you.