iOS --“`ALAssetLibrary`”中的显示图像

Question

我有ViewController1和ViewController2。ViewController1是UICollectionView，它使用ASAssetLibrary将缩略图加载到UICollectionViewCell中。

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!");}
 ];

当cell选择时，我希望将NSString或NSURL传递给ViewController2，以便它将调用并显示完整的分辨率图像。但是当NSLog网址：

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

我得到：

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

我试着换到[url path]，我得到：

asset.JPG

如何获得实际的照片url，以便将其转换为NSString以传递到ViewController2

Answer 1

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-----");
     }];

Answer 2

我的解决办法是：

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

Answer 3

显然，除了传递ALAsset之外，没有任何直接的解决方案。我就是这样做的：

在ViewController1 (也就是UICollectionViewController )中，我有一个函数：

- (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];

}

然后在ViewController2中有一个处理ALAsset的函数。

-(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;

}