element-ios/Vector/ViewController/MediaAlbumContentViewController.m

/*
 Copyright 2015 OpenMarket Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
 http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

#import "MediaAlbumContentViewController.h"


@interface MediaAlbumContentViewController ()
{
    /**
     Observe UIApplicationWillEnterForegroundNotification to refresh bubbles when app leaves the background state.
     */
    id UIApplicationWillEnterForegroundNotificationObserver;
    
    /**
     The current list of assets retrieved from collection.
     */
    PHFetchResult *assets;
}

@end

@implementation MediaAlbumContentViewController

#pragma mark - Class methods

+ (UINib *)nib
{
    return [UINib nibWithNibName:NSStringFromClass([MediaAlbumContentViewController class])
                          bundle:[NSBundle bundleForClass:[MediaAlbumContentViewController class]]];
}

+ (instancetype)mediaAlbumContentViewController
{
    return [[[self class] alloc] initWithNibName:NSStringFromClass([MediaAlbumContentViewController class])
                                          bundle:[NSBundle bundleForClass:[MediaAlbumContentViewController class]]];
}

#pragma mark -

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // Register collection view cell class
    [self.assetsCollectionView registerClass:MXKMediaCollectionViewCell.class forCellWithReuseIdentifier:[MXKMediaCollectionViewCell defaultReuseIdentifier]];
    
    if (!_mediaTypes)
    {
        // Set default media type
        self.mediaTypes = @[(NSString *)kUTTypeImage];
    }
    
    // Observe UIApplicationWillEnterForegroundNotification to refresh captures collection when app leaves the background state.
    UIApplicationWillEnterForegroundNotificationObserver = [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationWillEnterForegroundNotification object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *notif) {
        
        // Force a full refresh of the displayed collection
        self.assetsCollection = _assetsCollection;
        
    }];
}

- (void)dealloc
{
    
}

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

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    
    self.navigationItem.title = _assetsCollection.localizedTitle;
    
    [self.assetsCollectionView reloadData];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

#pragma mark -

- (void)setMediaTypes:(NSArray *)mediaTypes
{
    _mediaTypes = mediaTypes;
    
    self.assetsCollection = _assetsCollection;
}

- (void)setAssetsCollection:(PHAssetCollection *)assetsCollection
{
    if (assetsCollection)
    {
        if (!_mediaTypes)
        {
            // Set default media type
            _mediaTypes = @[(NSString *)kUTTypeImage];
        }
        
        // Set up fetch options.
        PHFetchOptions *options = [[PHFetchOptions alloc] init];
        options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
        if ([_mediaTypes indexOfObject:(NSString *)kUTTypeImage] != NSNotFound)
        {
            if ([_mediaTypes indexOfObject:(NSString *)kUTTypeMovie] != NSNotFound)
            {
                options.predicate = [NSPredicate predicateWithFormat:@"(mediaType == %d) || (mediaType == %d)", PHAssetMediaTypeImage, PHAssetMediaTypeVideo];
            }
            else
            {
                options.predicate = [NSPredicate predicateWithFormat:@"mediaType == %d",PHAssetMediaTypeImage];
            }
        }
        else if ([_mediaTypes indexOfObject:(NSString *)kUTTypeMovie] != NSNotFound)
        {
            options.predicate = [NSPredicate predicateWithFormat:@"mediaType == %d",PHAssetMediaTypeVideo];
        }
        
        assets = [PHAsset fetchAssetsInAssetCollection:assetsCollection options:options];
        
        NSLog(@"[MediaAlbumVC] lists %tu assets", assets.count);
    }
    else
    {
        assets = nil;
    }
    
    _assetsCollection = assetsCollection;

    self.navigationItem.title = _assetsCollection.localizedTitle;
    
    [self.assetsCollectionView reloadData];
}

#pragma mark - Override MXKViewController

- (void)destroy
{
    [super destroy];
}

#pragma mark - UICollectionViewDataSource

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return assets.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    MXKMediaCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:[MXKMediaCollectionViewCell defaultReuseIdentifier] forIndexPath:indexPath];
    
    // Sanity check: cancel pending asynchronous request (if any)
    if (cell.tag)
    {
        [[PHImageManager defaultManager] cancelImageRequest:(PHImageRequestID)cell.tag];
        cell.tag = 0;
    }
    
    if (indexPath.item < assets.count)
    {
        PHAsset *asset = assets[indexPath.item];
        
        CGFloat collectionViewSquareSize = ((collectionView.frame.size.width - 6) / 4); // Here 6 = 3 * cell margin (= 2).
        CGSize cellSize = CGSizeMake(collectionViewSquareSize, collectionViewSquareSize);
        
        PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];
        option.synchronous = NO;
        cell.tag = [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:cellSize contentMode:PHImageContentModeAspectFill options:option resultHandler:^(UIImage *result, NSDictionary *info) {
            
            cell.mxkImageView.contentMode = UIViewContentModeScaleAspectFill;
            cell.mxkImageView.image = result;
            cell.tag = 0;
            
        }];
        
        cell.topRightIcon.image = [UIImage imageNamed:@"icon_video"];
        cell.topRightIcon.hidden = (asset.mediaType == PHAssetMediaTypeImage);
        
        // Disable user interaction in mxkImageView, in order to let collection handle user selection
        cell.mxkImageView.userInteractionEnabled = NO;
    }
    
    return cell;
}

#pragma mark - UICollectionViewDelegate

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.item < assets.count && self.delegate)
    {
        [self.delegate mediaAlbumContentViewController:self didSelectAsset:assets[indexPath.item]];
    }
}

- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingCell:(nonnull UICollectionViewCell *)cell forItemAtIndexPath:(nonnull NSIndexPath *)indexPath
{
    // Check whether a asynchronous request is pending
    if (cell.tag)
    {
        [[PHImageManager defaultManager] cancelImageRequest:(PHImageRequestID)cell.tag];
        cell.tag = 0;
    }
}

#pragma mark - UICollectionViewDelegateFlowLayout

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.item < assets.count)
    {
        CGFloat collectionViewSquareSize = ((collectionView.frame.size.width - 6) / 4); // Here 6 = 3 * cell margin (= 2).
        CGSize cellSize = CGSizeMake(collectionViewSquareSize, collectionViewSquareSize);
        
        return cellSize;
    }
    return CGSizeZero;
}

@end