从从PHImageFileURLKey获得的URL中读取

Question

The Photo Framework for iOS 8 is able to return a URL for images using the PHImageFileURLKey. However I can't seem to read this URL. I only need read access. So far, any place I attempt to use the URL given, it is treated as though the file doesn't exist at all. How can I get data using the URL?

Code that successfully returns PHAssets and a URL:

PHFetchResult* phFetchResult = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeImage options:nil]
PHImageManager *manager = [PHImageManager defaultManager];
PHImageRequestOptions* options = [[PHImageRequestOptions alloc] init];
options.synchronous = YES; // Force sequential work. We have nothing to do until this block returns.
PHAsset* asset = [phFetchResult objectAtIndex:index];
[manager requestImageForAsset:asset targetSize:PHImageManagerMaximumSize contentMode:PHImageContentModeDefault options:options resultHandler:^(UIImage *resultImage, NSDictionary *info)
 {
     _image = resultImage;
     NSURL* fileURL = [info objectForKey:@"PHImageFileURLKey"];
     _imageLocation = [fileURL relativePath];
 }];

Code showing nothing found:

NSURL* fileURL = [info objectForKey:@"PHImageFileURLKey"];
NSLog(@"File exist?: %d", [[NSFileManager defaultManager] fileExistsAtPath:[fileURL relativePath]]);

My current workaround is to take the UIImage given and save it to the /tmp directory and then use that URL. It's not an ideal solution and I'd really like to know the purpose of the PHImageFileURLKey

Answer 1

I research on PHImageFileURLKey and i think there is no way to find image data by PHImageFileURLKey but you can find your image data by using asset local identifier instead of PHImageFileURLKey .

My code for your reference:

You can use your asset's local identifier and will get the image in response.

PHFetchResult *savedAssets = [PHAsset fetchAssetsWithLocalIdentifiers:@[asset.localIdentifier] options:nil];
    [savedAssets enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) {

        //this gets called for every asset from its localIdentifier you saved
        PHImageRequestOptions * imageRequestOptions = [[PHImageRequestOptions alloc] init];
        imageRequestOptions.synchronous = YES;
        imageRequestOptions.deliveryMode = PHImageRequestOptionsResizeModeFast;

        [[PHImageManager defaultManager]requestImageForAsset:asset targetSize:CGSizeMake(50,50) contentMode:PHImageContentModeAspectFill options:imageRequestOptions resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
            NSLog(@"get image from result");

        }];
    }];