Geek Answers Handbook

How to display video from ALAsset on UICollectionview ios

I tried the code under the code to get all the videos from the photo library using ALAsset . So far I want to display all the videos in a UICollectionview , but nothing seems to be displayed. Please give me some advice. Thanks in advance.

-ViewDidLoad (): get all videos from the photo library

 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]; [_collectionView reloadData]; } }]; } } failureBlock:^(NSError *error) { NSLog(@"error enumerating AssetLibrary groups %@\n", error); }];

-imageFromVideoURL ():

  - (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; }

Start displaying all video thumbnails in a 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]; return cell; }
+6
source share
2 answers

Replace this line: -

  [allVideos addObject:dic];

WITH

  [allVideos addObject: asset];

And in this method: -

 - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath { UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath]; NSLog(@"allvideo %@", allVideos); ALAsset *alasset = [allVideos objectAtIndex:indexPath.row]; yourImageView.image = [UIImage imageWithCGImage:alasset.thumbnail]; }
+1
source

First of all, take the [_collectionView reloadData] code from ALAssetsGroupEnumerationResultsBlock (the block you passed in -enumerateAssetsUsingBlock: , since it will call -reloadData for all found AVAssets.

There is an example MyImagePicker "application, available from apple, that does what you want to do. From there you can learn how to work.

0
source

More articles:


All Articles