7

我正在开发一个 iOS 应用程序，其中我需要像 Instagram 这样的画廊视图。我添加了画廊视图、相机视图和视频视图，在拍摄图像后它会保存到照片的自定义相册中。现在我想从自定义相册中检索这些图像并将其显示到画廊的收藏视图。但是我一直无法从自定义相册中检索这些图像。任何帮助将不胜感激。 检查图像以获取参考。

编辑：我添加了用于创建自定义相册的 PHPhotoLibrary，在此之前我添加了 AssetsLibrary 框架。

然后我创建了一个 NSObject 类 (CustomAlbum)，用于使用 PHPhotoLibrary 创建和管理自定义相册。

// 自定义相册.h

#import <Foundation/Foundation.h>
#import <Photos/Photos.h>


@interface CustomAlbum : NSObject

//Creating album with given name
+(void)makeAlbumWithTitle:(NSString *)title onSuccess:(void(^)(NSString *AlbumId))onSuccess onError: (void(^)(NSError * error)) onError;

//Get the album by name
+(PHAssetCollection *)getMyAlbumWithName:(NSString*)AlbumName;

//Add a image
+(void)addNewAssetWithImage:(UIImage *)image toAlbum:(PHAssetCollection *)album onSuccess:(void(^)(NSString *ImageId))onSuccess onError: (void(^)(NSError * error)) onError;

//get the image using identifier
+ (void)getImageWithIdentifier:(NSString*)imageId onSuccess:(void(^)(UIImage *image))onSuccess onError: (void(^)(NSError * error)) onError;


@end

// 自定义相册.m

#import "CustomAlbum.h"

@implementation CustomAlbum

#pragma mark - PHPhoto

+(void)makeAlbumWithTitle:(NSString *)title onSuccess:(void(^)(NSString *AlbumId))onSuccess onError: (void(^)(NSError * error)) onError
{
    //Check weather the album already exist or not
    if (![self getMyAlbumWithName:title]) {
        [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
            // Request editing the album.
            PHAssetCollectionChangeRequest *createAlbumRequest = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:title];

            // Get a placeholder for the new asset and add it to the album editing request.
            PHObjectPlaceholder * placeHolder = [createAlbumRequest placeholderForCreatedAssetCollection];
            if (placeHolder) {
                onSuccess(placeHolder.localIdentifier);
            }

        } completionHandler:^(BOOL success, NSError *error) {
            NSLog(@"Finished adding asset. %@", (success ? @"Success" : error));
            if (error) {
                onError(error);
            }
        }];
    }
}

+(void)addNewAssetWithImage:(UIImage *)image toAlbum:(PHAssetCollection *)album onSuccess:(void(^)(NSString *ImageId))onSuccess onError: (void(^)(NSError * error)) onError
{
    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        // Request creating an asset from the image.
        PHAssetChangeRequest *createAssetRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

        // Request editing the album.
        PHAssetCollectionChangeRequest *albumChangeRequest = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:album];

        // Get a placeholder for the new asset and add it to the album editing request.
        PHObjectPlaceholder * placeHolder = [createAssetRequest placeholderForCreatedAsset];
        [albumChangeRequest addAssets:@[ placeHolder ]];

        NSLog(@"%@",placeHolder.localIdentifier);
        if (placeHolder) {
            onSuccess(placeHolder.localIdentifier);
        }

    } completionHandler:^(BOOL success, NSError *error) {
        NSLog(@"Finished adding asset. %@", (success ? @"Success" : error));
        if (error) {
            onError(error);
        }
    }];
}


+(PHAssetCollection *)getMyAlbumWithName:(NSString*)AlbumName
{
    #if 0
    NSString * identifier = [[NSUserDefaults standardUserDefaults]objectForKey:kAlbumIdentifier];
    if (!identifier) return nil;
    PHFetchResult *assetCollections = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[identifier]
                                                                                           options:nil];
    #else
    PHFetchResult *assetCollections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                                               subtype:PHAssetCollectionSubtypeAlbumRegular
                                                                               options:nil];
    #endif
    NSLog(@"assetCollections.count = %lu", assetCollections.count);
    if (assetCollections.count == 0) return nil;

    __block PHAssetCollection * myAlbum;
    [assetCollections enumerateObjectsUsingBlock:^(PHAssetCollection *album, NSUInteger idx, BOOL *stop) {
        NSLog(@"album:%@", album);
        NSLog(@"album.localizedTitle:%@", album.localizedTitle);
        if ([album.localizedTitle isEqualToString:AlbumName]) {
            myAlbum = album;
            *stop = YES;
        }
    }];

    if (!myAlbum) return nil;
    return myAlbum;
}

+(NSArray *)getAssets:(PHFetchResult *)fetch
{
    __block NSMutableArray * assetArray = NSMutableArray.new;
    [fetch enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) {
        NSLog(@"asset:%@", asset);
        [assetArray addObject:asset];
    }];
    return assetArray;
}



+ (void)getImageWithIdentifier:(NSString*)imageId onSuccess:(void(^)(UIImage *image))onSuccess onError: (void(^)(NSError * error)) onError
{
    NSError *error = [[NSError alloc] init];
    PHFetchResult *assets = [PHAsset fetchAssetsWithLocalIdentifiers:@[imageId] options:nil];
    if (assets.count == 0) onError(error);

    NSArray * assetArray = [self getAssets:assets];
    PHImageManager *manager = [PHImageManager defaultManager];
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    [manager requestImageForAsset:assetArray.firstObject targetSize:screenRect.size contentMode:PHImageContentModeAspectFit options:nil resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
        onSuccess(result);
    }];
}

@end

然后使用此方法单击图像按钮以创建自定义相册并将图像保存在该自定义相册中。

 // Take Image Button Method

- (void)snapButtonPressed:(UIButton *)button
{
    [self.camera capture:^(LLSimpleCamera *camera, UIImage *image,
                           NSDictionary *metadata, NSError *error)
     {
         if(!error)
         {
             NSString * info = [NSString stringWithFormat:@"Size: %@  -  Orientation: %ld", NSStringFromCGSize(image.size), (long)image.imageOrientation];

             [CustomAlbum addNewAssetWithImage:image toAlbum:[CustomAlbum getMyAlbumWithName:CSAlbum] onSuccess:^(NSString *ImageId) {
                 NSLog(@"%@",ImageId);
                 recentImg = ImageId;
             } onError:^(NSError *error) {
                 NSLog(@"probelm in saving image");
             }];
         }
         else
         {
             NSLog(@"An error has occured: %@", error);
         }
     }
          exactSeenImage:YES];
}
4

2 回答 2

12

这是有效的代码。

__block PHAssetCollection *collection;

// Find the album
PHFetchOptions *fetchOptions = [[PHFetchOptions alloc] init];
fetchOptions.predicate = [NSPredicate predicateWithFormat:@"title = %@", @"YOUR_CUSTOM_ALBUM_NAME"];
collection = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                  subtype:PHAssetCollectionSubtypeAny
                                                  options:fetchOptions].firstObject;

PHFetchResult *collectionResult = [PHAsset fetchAssetsInAssetCollection:collection options:nil];

[collectionResult enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) {


    //add assets to an array for later use in the uicollectionviewcell

}];
于 2016-05-30T08:04:44.473 回答
5

只需尝试一次此代码..您可以使用此代码在一个数组中获取所有图像：-

-(void)getAllPictures
{

    __block PHAssetCollection *collection;

    // Find the album
    PHFetchOptions *fetchOptions = [[PHFetchOptions alloc] init];
    fetchOptions.predicate = [NSPredicate predicateWithFormat:@"title = %@", @"YOUR_CUSTOM_ALBUM_NAME"];
    collection = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                          subtype:PHAssetCollectionSubtypeAny
                                                          options:fetchOptions].firstObject;

    PHFetchResult *collectionResult = [PHAsset fetchAssetsInAssetCollection:collection options:nil];

    NSMutableArray *assets = [[NSMutableArray alloc] init];

    [collectionResult enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) {
        [assets addObject:asset];

    }];

    PHImageRequestOptions * requestOptions = [[PHImageRequestOptions alloc] init];
    //requestOptions.resizeMode   = PHImageRequestOptionsResizeModeExact;
    //requestOptions.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat;

    // this one is key
    //requestOptions.synchronous = true;


    PHImageManager *manager = [PHImageManager defaultManager];
    NSMutableArray *images = [NSMutableArray arrayWithCapacity:[assets count]];

    // assets contains PHAsset objects.
    __block UIImage *ima;

    for (PHAsset *asset in assets) {
        // Do something with the asset

        [manager requestImageForAsset:asset
                           targetSize:PHImageManagerMaximumSize//CGSizeMake(300, 300)
                          contentMode:PHImageContentModeDefault
                              options:requestOptions
                        resultHandler:^void(UIImage *image, NSDictionary *info) {
                            ima = image;

                            [images addObject:ima];
                        }];
    }

    NSLog(@"images %@", images); //You will get all images into this images array.

}

有关更多详细信息，请参阅使用照片框架的示例应用程序。

希望，这就是你要找的。任何问题都可以回复我。:)

于 2016-08-17T09:14:08.060 回答