如何获取刚刚添加到PHPhotoLibrary中的图像的URL

问题描述

我在两种情况下使用UIImagePickerController

I am using the UIImagePickerController in two cases

• 选择照片库中的现有图像


• 拍摄新照片

在第一种情况下，当我从库中选择图像时，我可以很容易地得到委托方法中的URL：

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];
    ...
}

但是当我拍摄新照片时，图片尚未在照片库中，并且还没有网址。所以，我首先需要在库中添加图像。但是，如何获取新资产的URL？

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?

这是我在图片库中添加图片的代码

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 ?
            ...
        }
    ];
}

推荐答案

我没有找到获取URL的方法，但也许localIdentifier可以帮助你做同样的工作。

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

使用

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

获取本地ID并稍后获取图片。

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;
        }];
    }
}];

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