How to display video from ALAsset to UICollectionview Cell - objective-c

Question

I tried this code to add all ALAsset created video into my app and then play it. But the video doesn't show in UICollectionView. How is it possible?
I write this code in View Did Load.
_collectionView.dataSource=self;
_collectionView.delegate=self;
[self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:#"cellIdentifier"];
_allVideos = [[NSMutableArray alloc] init];
ALAssetsLibrary *assetLibrary = [[ALAssetsLibrary alloc] init];
[assetLibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop)
{
if (group)
{
[group setAssetsFilter:[ALAssetsFilter allVideos]];
[group enumerateAssetsUsingBlock:^(ALAsset *asset, NSUInteger index, BOOL *stop)
{
if (asset)
{
_dic = [[NSMutableDictionary alloc] init];
ALAssetRepresentation *defaultRepresentation = [asset defaultRepresentation];
NSString *uti = [defaultRepresentation UTI];
NSURL *videoURL = [[asset valueForProperty:ALAssetPropertyURLs] valueForKey:uti];
NSString *title = [NSString stringWithFormat:#"video %d", arc4random()%100];
UIImage *image = [self imageFromVideoURL:videoURL];
[_dic setValue:image forKey:#"image"];
[_dic setValue:title forKey:#"name"];
[_dic setValue:videoURL forKey:#"url"];
//[_allVideos addObject:_dic];
[_allVideos addObject:asset];
[_collectionView reloadData];
}
}];
}
}
failureBlock:^(NSError *error)
{
NSLog(#"error enumerating AssetLibrary groups %#\n", error);
}];
}
And One method is
- (UIImage *)imageFromVideoURL:(NSURL*)videoURL
{
// result
UIImage *image = nil;
// AVAssetImageGenerator
AVAsset *asset = [[AVURLAsset alloc] initWithURL:videoURL options:nil];;
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
imageGenerator.appliesPreferredTrackTransform = YES;
// calc midpoint time of video
Float64 durationSeconds = CMTimeGetSeconds([asset duration]);
CMTime midpoint = CMTimeMakeWithSeconds(durationSeconds/2.0, 600);
// get the image from
NSError *error = nil;
CMTime actualTime;
CGImageRef halfWayImage = [imageGenerator copyCGImageAtTime:midpoint actualTime:&actualTime error:&error];
if (halfWayImage != NULL)
{
// CGImage to UIImage
image = [[UIImage alloc] initWithCGImage:halfWayImage];
[_dic setValue:image forKey:#"name"];
NSLog(#"Values of dictionary==>%#", _dic);
NSLog(#"Videos Are:%#",videoURL);
CGImageRelease(halfWayImage);
}
return image;
}
And I wrote this in UICollectionView:
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return _allVideos.count;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cellIdentifier" forIndexPath:indexPath];
NSLog(#"allvideo %#", _allVideos);
ALAsset *alasset = [_allVideos objectAtIndex:indexPath.row];
UIImageView *imageview=[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 80, 80)];
imageview.image = [UIImage imageWithCGImage:alasset.thumbnail];
[cell.contentView addSubview:imageview];
return cell;
}

Answer 1

Write the code in ViewDidLoad
assets = [[NSMutableArray alloc] init];
_library = [[ALAssetsLibrary alloc] init];
UIImage *viewImage;
[_library writeImageToSavedPhotosAlbum:[viewImage CGImage] orientation:(ALAssetOrientation)[viewImage imageOrientation] completionBlock:^(NSURL *assetURL, NSError *error){
if (error) {
NSLog(#"error");
} else {
NSLog(#"url %#", assetURL);
}
}];
[_library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop){
if (group != NULL) {
[group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop){
if ([[result valueForProperty:ALAssetsGroupPropertyName] isEqual:#"VideoMaker"]) {
NSLog(#"asset: %#", result);
[assets addObject:result];
}
}];
}
[self.collectionView reloadData];
//[self.activity stopAnimating];
//[self.activity setHidden:YES];
}
failureBlock:^(NSError *error){
NSLog(#"failure"); }];`} `
In this assets is NSMutableArray and library is the ALAssetLibrary.
In UIcollectionviewcell cell for rowAtIndexpath method
-(VideoCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
VideoCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"CELL" forIndexPath:indexPath];
ALAsset *asset = [assets objectAtIndex:indexPath.row];
[cell.videoImageView setImage:[UIImage imageWithCGImage:[asset thumbnail]]];
return cell;
}