How to get the URL of an image just added in PHPho

问题:

I am using the UIImagePickerController in two cases

• to select an existing image in the Photo Library
• to take a new picture

In the first case, when I choose an image form the library, I can easily get the URL in the delegate method:

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    // Get the URL
    NSURL *url = [info valueForKey:UIImagePickerControllerReferenceURL];
    ...
}

But when I take a new picture, the image is not yet in the photo library and has no URL yet. So, I first need to add the image in the Library. But then, how to get the URL of the new asset?

Here is my code to add the image in the Photo Library

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    // Get the image
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];

    // Add the image in the library
    [[PHPhotoLibrary sharedPhotoLibrary]

        performChanges:^
        {
            // Request creating an asset from the image.
            PHAssetChangeRequest *createAssetRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

            // Get the URL of the new asset here ?
            ...
        }

        completionHandler:^(BOOL success, NSError *error)
        {
            if (!success) { ...; return; }

            // Get the URL of the new asset here ?
            ...
        }
    ];
}

回答1:

I didn't find the way to get URL, but maybe localIdentifier can help you do the same work.

use

NSString* localId = [[assetChangeRequest placeholderForCreatedAsset] localIdentifier];

to get the local ID and get the image later.

__block NSString* localId;
// Add it to the photo library
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
    PHAssetChangeRequest *assetChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

    if (self.assetCollection) {
        PHAssetCollectionChangeRequest *assetCollectionChangeRequest = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:self.assetCollection];
        [assetCollectionChangeRequest addAssets:@[[assetChangeRequest placeholderForCreatedAsset]]];
    }
    localId = [[assetChangeRequest placeholderForCreatedAsset] localIdentifier];
} completionHandler:^(BOOL success, NSError *error) {
    PHFetchResult* assetResult = [PHAsset fetchAssetsWithLocalIdentifiers:@[localId] options:nil];
    if (!success) {
        NSLog(@"Error creating asset: %@", error);
    } else {
        PHFetchResult* assetResult = [PHAsset fetchAssetsWithLocalIdentifiers:@[localId] options:nil];
        PHAsset *asset = [assetResult firstObject];
        [[PHImageManager defaultManager] requestImageDataForAsset:asset options:nil resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) {
            UIImage* newImage = [UIImage imageWithData:imageData];
            self.imageView.image = newImage;
        }];
    }
}];

回答2:

If we use the ALAssetsLibrary, it is very simple to save a picture in the Photo Album and get its URL:

    // Get the image
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];

    // Add the image in the Photo Library
    ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
    [library writeImageToSavedPhotosAlbum: [image CGImage]
                              orientation: (ALAssetOrientation)[image imageOrientation]
                          completionBlock: ^(NSURL *assetURL, NSError *error)
    {
        if (error)
        {
            NSLog( @"error: %@", error );
        }
        else
        {
            NSLog( @"assetURL = %@", assetURL );
        }
    }];

But surprisingly it seems not possible to do the same thing with the new PHPhotoLibrary!

A solution to have the same result with PHPhotoLibrary is always welcome.

回答3:

I don't like this fix, as this could result in a race condition. So far I can't think of a better solution. If someone does I'd love to hear it :) Either way, here is a Swift-version of Rigel Chen's answer

import Photos

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {

    if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {

        var localId:String?
        let imageManager = PHPhotoLibrary.sharedPhotoLibrary()

        imageManager.performChanges({ () -> Void in

            let request = PHAssetChangeRequest.creationRequestForAssetFromImage(image)
            localId = request.placeholderForCreatedAsset?.localIdentifier

            }, completionHandler: { (success, error) -> Void in
                dispatch_async(dispatch_get_main_queue(), { () -> Void in

                    if let localId = localId {

                        let result = PHAsset.fetchAssetsWithLocalIdentifiers([localId], options: nil)
                        let assets = result.objectsAtIndexes(NSIndexSet(indexesInRange: NSRange(location: 0, length: result.count))) as? [PHAsset] ?? []

                        if let asset = assets.first {
                            // Do something with result
                        }
                    }
                })
        })
    }
}

回答4:

Swift 4 solution that works for me to get the url of last image in Photo Library:

let fetchOptions = PHFetchOptions()
fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: true)]
let fetchResult = PHAsset.fetchAssets(with: .image, options: fetchOptions).lastObject
PHImageManager().requestAVAsset(forVideo: fetchResult!, options: nil, resultHandler { (avurlAsset, _, _) in
    if let newObj = avurlAsset as? AVURLAsset {
        print(newObj.url)
    }
})

Hope it helps!

回答5:

[Swift 4] This method can handle both image and video, enjoy :)

func getURL(of asset: PHAsset, completionHandler : @escaping ((_ responseURL : URL?) -> Void)) {

    if asset.mediaType == .image {
        let options: PHContentEditingInputRequestOptions = PHContentEditingInputRequestOptions()
        options.canHandleAdjustmentData = {(adjustmeta: PHAdjustmentData) -> Bool in
            return true
        }
        asset.requestContentEditingInput(with: options, completionHandler: { (contentEditingInput, info) in
            completionHandler(contentEditingInput!.fullSizeImageURL)
        })
    } else if asset.mediaType == .video {
        let options: PHVideoRequestOptions = PHVideoRequestOptions()
        options.version = .original
        PHImageManager.default().requestAVAsset(forVideo: asset, options: options, resultHandler: { (asset, audioMix, info) in
            if let urlAsset = asset as? AVURLAsset {
                let localVideoUrl = urlAsset.url
                completionHandler(localVideoUrl)
            } else {
                completionHandler(nil)
            }
        })
    }
}

回答6:

Retrieve image URL:

- (void)processImage:(UIImage*)image type:(NSString*)mimeType forCallbackId:(NSString*)callbackId
    {
        __block NSString* localId;

        // Add it to the photo library
        [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
            PHAssetChangeRequest *assetChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

            localId = [[assetChangeRequest placeholderForCreatedAsset] localIdentifier];
        } completionHandler:^(BOOL success, NSError *err) {
            if (!success) {
                NSLog(@"Error saving image: %@", [err localizedDescription]);
            } else {
                PHFetchResult* assetResult = [PHAsset fetchAssetsWithLocalIdentifiers:@[localId] options:nil];
                PHAsset *asset = [assetResult firstObject];
                [[PHImageManager defaultManager] requestImageDataForAsset:asset
                                                                  options:nil
                                                            resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) {
                    NSURL *fileUrl = [info objectForKey:@"PHImageFileURLKey"];
                    if (fileUrl) {
                        NSLog(@"Image path: %@", [fileUrl relativePath]);
                    } else {
                        NSLog(@"Error retrieving image filePath, heres whats available: %@", info);
                    }
                }];
            }
        }];
    }