如何从照片自定义相册，iOS SDK获取图像？ [英] How to get images from Custom album of Photos, iOS SDK?

问题描述

我正在开发一款iOS应用，我需要像Instagram这样的画廊视图。我已经添加了图库视图，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图库的集合视图中。但是我在从自定义相册中检索这些图片时遇到困难。任何帮助将不胜感激。

I'm working on an iOS app in which I need gallery view like Instagram. I have added gallery View, camera View and video View, after taking image it saves to custom album of Photos. Now I want to retrieve those images from custom album and show it to Collection view of Gallery. But I'm getting stuck in retrieving those images from custom album. Any help will be appreciated.

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。

I added the PHPhotoLibrary for creating custom photo album, before this I added AssetsLibrary framework.

An然后我创建了一个NSObject类（CustomAlbum）来创建使用PHPhotoLibrary管理自定义相册。

An Then I created a NSObject class (CustomAlbum) for creating and managing the custom photo album using PHPhotoLibrary.

// CustomAlbum.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

// CustomAlbum。 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在该自定义相册中保存图像。

And then use this method on take Image Button click to create custom album and save images in that custom album.

 // 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];
}

推荐答案

这是有效的代码。

Here is the code that works.

__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

}];

这篇关于如何从照片自定义相册，iOS SDK获取图像？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！