PhotoKit的使用

导入 Photos.framework 并导入头文件

#import

ios8-photo-kit.png

PHAsset : 一个资源, 比如一张图片 / 一段视频
PHAssetCollection : 一个相簿
PHImageManager: 用于处理资源的加载，加载图片的过程带有缓存处理，可以通过传入一个 PHImageRequestOptions 控制资源的输出尺寸等规格
PHImageRequestOptions: 控制加载图片时的一系列参数 图片管理者,是单例,发送请求才能从asset获取图片

// 列出所有相册智能相册
    PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];

 for (PHAssetCollection *albums in smartAlbums) {
       PHFetchResult *result = [PHAsset fetchAssetsInAssetCollection:albums options:nil];
        for (PHAsset *asset in result) {
            NSLog(@"%@",asset);
            [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:/*CGSizeMake(pixSize, pixSize) */PHImageManagerMaximumSize contentMode:PHImageContentModeAspectFill options:nil resultHandler:^(UIImage * _Nullable image, NSDictionary * _Nullable info) {                
                if (image) {
                    [self.arr addObject:image];
                }
            }];
        }
    }

// 列出所有用户创建的相册
PHFetchResult *topLevelUserCollections = [PHCollectionList fetchTopLevelUserCollectionsWithOptions:nil];
  
// 获取所有资源的集合，并按资源的创建时间排序
PHFetchOptions *options = [[PHFetchOptions alloc] init];
options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:YES]];
PHFetchResult *assetsFetchResults = [PHAsset fetchAssetsWithOptions:options];

//获得所有相簿中的缩略图
- (void)getThumbnailImages
{
    // 获得所有的自定义相簿
    PHFetchResult *assetCollections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
    // 遍历所有的自定义相簿
    for (PHAssetCollection *assetCollection in assetCollections) {
        [self enumerateAssetsInAssetCollection:assetCollection original:NO];
    }
    // 获得相机胶卷
    PHAssetCollection *cameraRoll = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary options:nil].lastObject;
    [self enumerateAssetsInAssetCollection:cameraRoll original:NO];
}

/**
 *  遍历相簿中的所有图片
 *  @param assetCollection 相簿
 *  @param original        是否要原图
 */
- (void)enumerateAssetsInAssetCollection:(PHAssetCollection *)assetCollection original:(BOOL)original
{
    NSLog(@"相簿名:%@", assetCollection.localizedTitle);
    
    PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
    // 同步获得图片, 只会返回1张图片
    options.synchronous = YES;
    
    // 获得某个相簿中的所有PHAsset对象
    PHFetchResult *assets = [PHAsset fetchAssetsInAssetCollection:assetCollection options:nil];
    for (PHAsset *asset in assets) {
        // 是否要原图
        CGSize size = original ? CGSizeMake(asset.pixelWidth, asset.pixelHeight) : CGSizeZero;
        
        // 从asset中获得图片
        [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:size contentMode:PHImageContentModeDefault options:options resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
            NSLog(@"%@", result);
        }];
    }
}

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