iOS - display image from `ALAssetLibrary`

Question

I have ViewController1 and ViewController2. ViewController1 is UICollectionView and it use ASAssetLibrary to load thumbnail into UICollectionViewCell:

NSMutableArray *collector = [[NSMutableArray alloc] initWithCapacity:0];
ALAssetsLibrary *al = [TemplateEditBarController defaultAssetsLibrary];
[al enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos
                  usingBlock:^(ALAssetsGroup *group, BOOL *stop)
 {
     [group enumerateAssetsUsingBlock:^(ALAsset *asset, NSUInteger index, BOOL *stop)
      {
          if (asset) {
              [collector addObject:asset];
          }
      }];
     assetsarray = collector;//<--assetsarray is local.
 }
                failureBlock:^(NSError *error) { NSLog(@"fail!");}
 ];

When cell selected, I want to pass either NSString or NSURL to ViewController2 so that it will call and display the full resolution image. But when NSLog the url:

ALAsset* asset = backgroundsarray[row];
    ALAssetRepresentation *representation = [asset defaultRepresentation];
    NSURL *url = [representation url];
    newbg = [url absoluteString];//<-NSLog this.

I get:

assets-library://asset/asset.JPG?id=6E5438ED-9A8C-4ED0-9DEA-AB2D8F8A9360&ext=JPG

I tried change to [url path] I get:

asset.JPG

How can I get the actual photo url so that I can convert to NSString to pass to ViewController2?

http://stackoverflow.com/questions/3837115/display-image-from-url-retrieved-from-alasset-in-iphone see the URL — Ashok Londhe, May 13 '15 at 04:42

score 2 · Answer 1 · answered May 13 '15 at 05:07

NSURL* aURL = [NSURL URLWithString:imagePath];        
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library assetForURL:aURL resultBlock:^(ALAsset *asset)
     {
         UIImage  *image = [UIImage imageWithCGImage:[[asset defaultRepresentation] fullScreenImage] scale:0.5 orientation:UIImageOrientationUp];             
         imageView.image=image;             

     }
            failureBlock:^(NSError *error)
     {
         // error handling
         NSLog(@"failure-----");
     }];

score 1 · Answer 2 · answered Oct 18 '16 at 04:38

1

My solution here:

ALAssetsLibrary *assetslibrary = [[ALAssetsLibrary alloc] init];
[assetslibrary assetForURL:assetURL resultBlock:^(ALAsset *asset) {
    if (asset) {
       image = [UIImage imageWithCGImage:[asset aspectRatioThumbnail]];
    }
}

answered Oct 18 '16 at 04:38

giapnh

2,950
24
20

But i don't know why the loaded image have the resolution that isn't full. – giapnh Oct 18 '16 at 04:40

score 0 · Answer 3 · answered May 13 '15 at 13:01

Apparently there isn't any direct solution other than passing ALAsset. This is what I do:

In ViewController1, which is UICollectionViewController, I have this function:

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
//NSLog(@"selected row: %ld",(long)indexPath.row);
long row = [indexPath row];
NSString* newbg = [[NSString alloc]init];
if ([bartype isEqualToString:@"photolibrary"]) {
    ALAsset* asset = backgroundsarray[row];
    [_delegate changeBackgroundWithAsset:asset];

}

Then I have a function in ViewController2 to process ALAsset:

-(void)changeBackgroundWithAsset:(ALAsset*)b{
ALAssetRepresentation *rep = [b defaultRepresentation];
CGImageRef iref = [rep fullResolutionImage];
UIImage *bimage;
bimage = [UIImage imageWithCGImage:iref];
UIImageView* bgview = [[UIImageView alloc]init];
bgview = curbgview;
bgview.image = bimage;

}

iOS - display image from `ALAssetLibrary`

3 Answers3