How To Create A Gallery on iOS

Question

I\'m starting to develop a simple application for iOS, and this application is a simple gallery of some photo (taken from a website). The first problem I encountered is how

Answer 1

I did something very similar to this in a project of my own. I just show some parts of the code here, but if you want to view the full code you can view it on GitHub GitHub Repo

First I made a custom Collection View cell with an ImageView

in CustomCollectionCell.h

#import 

@interface CustomCollectionCell : UICollectionViewCell

@property (nonatomic , retain) UIImageView *imageView;
@end

in CustomCollectionCell.m

#import "CustomCollectionCell.h"

@implementation CustomCollectionCell
- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        [self setupImageView];
    }
    return self;
}

#pragma mark - Create Subviews

- (void)setupImageView {
    self.imageView = [[UIImageView alloc] initWithFrame:self.bounds];
    self.imageView.autoresizingMask = UIViewAutoresizingNone;//UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    [self addSubview:self.imageView];
}

@end

Then in the view where you want to have the thumbnails you set up the CollectionView

in ThumbNailViewController.m (snippet)

UICollectionView *collectionViewThumbnails;

in ThumbNailViewController.m (snippet)

UICollectionViewFlowLayout *layout=[[UICollectionViewFlowLayout alloc] init];
collectionViewThumbnails=[[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height - 50) collectionViewLayout:layout];
if (collectionViewThumbnails && layout)
{
    [collectionViewThumbnails setDataSource:self];
    [collectionViewThumbnails setDelegate:self];
    [collectionViewThumbnails registerClass:[CustomCollectionCell class] forCellWithReuseIdentifier:@"cellIdentifier"];
    [collectionViewThumbnails setBackgroundColor:[UIColor blackColor]];

    [self.view addSubview:collectionViewThumbnails];
}

Then you have the required methods for the collection views. Here you can set up what you

//Number of items in the collectionview
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [galleryData count];
}

//Set up what each cell in the collectionview will look like
//Here is where you add the thumbnails and the on define what happens when the cell is clicked 
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    //initialize custom cell for the collectionview
    CustomCollectionCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];

    [cell.imageView setClipsToBounds:YES];

    cell.imageView.contentMode = UIViewContentModeScaleAspectFill;

    //format url to load image from
    NSString *url = [NSString stringWithFormat:@"http://andrecphoto.weebly.com/uploads/6/5/5/1/6551078/%@",galleryData[indexPath.item]];

    //load thumbnail
    [cell.imageView setImageWithURL:[NSURL URLWithString:url]
                   placeholderImage:[UIImage imageNamed:@"placeholder.png"]];

    //Sets up taprecognizer for each cell. (onlcick)
    UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)];
    [cell addGestureRecognizer:tap];

    //sets cell's background color to black
    cell.backgroundColor=[UIColor blackColor];
    return cell;
}

//Sets size of cells in the collectionview
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(100, 100);
}

//Sets what happens when a cell in the collectionview is selected (onlclicklistener)
- (void)handleTap:(UITapGestureRecognizer *)recognizer  {
    //gets the cell thats was clicked
    CustomCollectionCell *cell_test = (CustomCollectionCell *)recognizer.view;

    //gets indexpath of the cell
    NSIndexPath *indexPath = [collectionViewThumbnails indexPathForCell:cell_test];

    if (isConnectedGal)
    {
        //sets the image that will be displayed in the photo browser
        [photoGallery setInitialPageIndex:indexPath.row];

        //pushed photobrowser
        [self.navigationController pushViewController:photoGallery animated:YES];
    }
}

Hopefully that answers your question.