Get the filename of image saved to photos album

问题:

Gain a huge bounty with this seemingly easy question that has no attention.

In modern iOS (2017),

here's actually the only way I know to save an image to the iOS photos system, and get the filename/path.

import UIKit
import Photos

func saveTheImage... () {

    UIImageWriteToSavedPhotosAlbum(yourUIImage, self,
        #selector(Images.image(_:didFinishSavingWithError:contextInfo:)),
        nil)
}

func image(_ image: UIImage, didFinishSavingWithError error: NSError?, contextInfo: UnsafeRawPointer) {
    guard error == nil else {
        print("Couldn't save the image!")
        return
    }
    doGetFileName()
}

func doGetFileName() {
    let fo: PHFetchOptions = PHFetchOptions()
    fo.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
    let r = PHAsset.fetchAssets(with: PHAssetMediaType.image, options: fo)
    if let mostRecentThingy = r.firstObject {

        PHImageManager.default().requestImageData(
            for: mostRecentThingy,
            options: PHImageRequestOptions(),
            resultHandler: { (imagedata, dataUTI, orientation, info) in

                if info!.keys.contains("PHImageFileURLKey") {
                    let path = info!["PHImageFileURLKey"] as! NSURL

                    print("Holy cow. The path is \(path)")
                }
                else { print("bizarre problem") }
            })

    }
    else { print("unimaginable catastrophe") }
}

There are two problems with this:

1. WTH ?!?

2. It fails in racetrack conditions.

This is amazingly unwieldy, and it seems worrysome in a number of ways.

Is it really the way to go, today?

回答1:

extension PHPhotoLibrary {

    func save(imageData: Data, withLocation location: CLLocation?) -> Promise<PHAsset> {
        var placeholder: PHObjectPlaceholder!
        return Promise { fullfil, reject in
            performChanges({
                let request = PHAssetCreationRequest.forAsset()
                request.addResource(with: .photo, data: imageData, options: .none)
                request.location = location
                placeholder = request.placeholderForCreatedAsset
            }, completionHandler: { (success, error) -> Void in
                if let error = error {
                    reject(error)
                    return
                }

                guard let asset = PHAsset.fetchAssets(withLocalIdentifiers: [placeholder.localIdentifier], options: .none).firstObject else {
                    reject(NSError())
                    return
                }

                fullfil(asset)
            })
        }
    }
}

I think you can do this with PHPhotoLibrary and PHObjectPlaceholder.

回答2:

You just saved image programmatically, so you can get the image from camera and save it with your path:

//save image in Document Derectory
      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
      NSString *documentsDirectory = [paths objectAtIndex:0];
      NSLog(@"Get Path : %@",documentsDirectory);

      //create Folder if Not Exist
      NSError *error = nil;
      NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"/YourFolder"];

      if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
        [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error]; //Create folder

      NSString *yourPhotoName=@"YourPhotoName";
      NSString* path= [dataPath stringByAppendingString:[NSString stringWithFormat:@"/%@.png",yourPhotoName]];
      NSData* imageData = UIImagePNGRepresentation(imageToSaved); //which got from camera

      [imageData writeToFile:path atomically:YES];

      imagePath = path;
      NSLog(@"Save Image Path : %@",imagePath);

回答3:

Maybe this is a different approach but here's what I'm doing in my app and I'm satisfied with it:

func saveImage(image: UIImage, name: String) {

    var metadata = [AnyHashable : Any]()
    let iptcKey = kCGImagePropertyIPTCDictionary as String
    var iptcMetadata = [AnyHashable : Any]()

    iptcMetadata[kCGImagePropertyIPTCObjectName as String] = name
    metadata[iptcKey] = iptcMetadata

    let library = ALAssetsLibrary()

    library.writeImage(toSavedPhotosAlbum: image.cgImage, metadata: metadata) { url, error in

        // etc...
    }
}

If you don't want to use ALAssetsLibrary, you'll probably be interested in this answer.