如何将选定的集合视图单元格的图像推送到另一个视图控制器？

Question

Can anyone please help me... I already have a collection view that displays all images from a free database on Parse.com. I need to pass the image of the selected cell to another view controller. I've already have the code for prepareForSegue, my problem is that I can't get the value of the selected cell. here's my codes..

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return 1;
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return [imageArray count];
}


-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *cellIdentifier = @"imageCell";
    GalleryCell *cell = (GalleryCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

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

    cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"photo-frame.png"]];

     cell.loadingSpinner.hidden = NO;
     [cell.loadingSpinner startAnimating];

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

    return cell;
}



- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {

// should I put anything here? the collection view display images even its blank

}

//segue transfer data
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{

    UINavigationController *nav = [segue destinationViewController];
    DetailedVC *transferViewController = (DetailedVC *)nav.topViewController;

    NSLog(@"prepareForSegue: %@", segue.identifier);
    if([segue.identifier isEqualToString:@"detailView"])
    {
        //here is my problem... what should I put here????
    }
}

I've already put codes to viewDidLoad of the recipient view controller

Answer 1

You need to make use of Delegate/Protocol.

Set the View controller that you want to send code to as a delegate in your .h file:

@interface NewSubmissionTableViewController : UITableViewController<PhotoPickerViewControllerDelegate>

import the view controller you want to send the image to at the top of your .h file.

#import "PhotoPickerViewController.h"

Instantiate the VC you are sending the image too and set a variable within that class equal to the variable you want it to have access to.

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    PhotoPickerViewController *photoPicker = segue.destinationViewController;
    photoPicker.delegate = self;
    photoPicker.selectedPhotos = self.pictureCollection;
}

Answer 2

(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    [self prepareForSegue:<#(UIStoryboardSegue *)#> sender:<#(id)#>]
}

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    UINavigationController *nav = [segue destinationViewController];
    DetailedVC *transferViewController = (DetailedVC *)nav.topViewController;

    NSLog(@"prepareForSegue: %@", segue.identifier);

    if([segue.identifier isEqualToString:@"detailView"])
    {
        transferViewController.xxx = sender;
    }
}