iOS8.0 使用Photos.framework对相册的常用操作

转载自：http://blog.csdn.net/longitachi/article/details/50130957

1.判断相册访问权限

首先我们访问相册，肯定有需要判断是否有访问权限的时候，然后做出相应的操作

PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
if (status == PHAuthorizationStatusRestricted ||
    status == PHAuthorizationStatusDenied) {
    // 这里便是无访问权限
}

2.实时监听相册内部图片变化

[[PHPhotoLibrary sharedPhotoLibrary] registerChangeObserver:self];

当然，这个"self"是要遵守 PHPhotoLibraryChangeObserver 协议的

 

回调方法如下，不过这个地方是有一个坑的，就是这个回调是在一个子线程里面，如果你想要对UI进行操作的话，则必须回调主线程

//相册变化回调
- (void)photoLibraryDidChange:(PHChange *)changeInstance
{
    dispatch_sync(dispatch_get_main_queue(), ^{
        // your codes
    });
}

3.读取相册内所有图片资源

对相册资源的相关操作，apple多都放在了 PHAsset内

#pragma mark - 获取相册内所有照片资源
- (NSArray<PHAsset *> *)getAllAssetInPhotoAblumWithAscending:(BOOL)ascending
{
    NSMutableArray<PHAsset *> *assets = [NSMutableArray array];

    PHFetchOptions *option = [[PHFetchOptions alloc] init];
    //ascending 为YES时，按照照片的创建时间升序排列;为NO时，则降序排列
    option.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:ascending]];

    PHFetchResult *result = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeImage options:option];

    [result enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        PHAsset *asset = (PHAsset *)obj;
        NSLog(@"照片名%@", [asset valueForKey:@"filename"]);
        [assets addObject:asset];
    }];

    return assets;
}

4.根据获取的PHAsset对象，解析图片

PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];
    //仅显示缩略图，不控制质量显示
    /**
     PHImageRequestOptionsResizeModeNone,
     PHImageRequestOptionsResizeModeFast, //根据传入的size，迅速加载大小相匹配(略大于或略小于)的图像
     PHImageRequestOptionsResizeModeExact //精确的加载与传入size相匹配的图像
     */
    option.resizeMode = PHImageRequestOptionsResizeModeFast;
    option.networkAccessAllowed = YES;
    //param：targetSize 即你想要的图片尺寸，若想要原尺寸则可输入PHImageManagerMaximumSize
    [[PHCachingImageManager defaultManager] requestImageForAsset:asset targetSize:size contentMode:PHImageContentModeAspectFit options:option resultHandler:^(UIImage * _Nullable image, NSDictionary * _Nullable info) {
        //解析出来的图片
    }];

5.获取所有智能相册（即默认的，如“所有照片”“屏幕快照”等）

PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
[smartAlbums enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL *stop) {
    NSLog(@"相册名字:%@", collection.localizedTitle);
}];

智能相册的title不出意外都是英文，下面提供一个对应的中文名

- (NSString *)transformAblumTitle:(NSString *)title
{
    if ([title isEqualToString:@"Slo-mo"]) {
        return @"慢动作";
    } else if ([title isEqualToString:@"Recently Added"]) {
        return @"最近添加";
    } else if ([title isEqualToString:@"Favorites"]) {
        return @"最爱";
    } else if ([title isEqualToString:@"Recently Deleted"]) {
        return @"最近删除";
    } else if ([title isEqualToString:@"Videos"]) {
        return @"视频";
    } else if ([title isEqualToString:@"All Photos"]) {
        return @"所有照片";
    } else if ([title isEqualToString:@"Selfies"]) {
        return @"自拍";
    } else if ([title isEqualToString:@"Screenshots"]) {
        return @"屏幕快照";
    } else if ([title isEqualToString:@"Camera Roll"]) {
        return @"相机胶卷";
    }
    return nil;
}

在项目plist配置文件中添加如下键，值设为YES，即可自动匹配手机系统语言，返回相册名字。不需要进行上列判断

Localized resources can be mixed YES
//或者右键plist文件Open As->Source Code 添加
<key>CFBundleAllowMixedLocalizations</key>
<true/>

6.获取所有用户创建的相册

PHFetchResult *userAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary options:nil];
[userAlbums enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL * _Nonnull stop) {
    NSLog(@"相册名字:%@", collection.localizedTitle);
}];

7.获取每个相册下的所有照片对象(PHAsset)

#pragma mark - 获取指定相册内的所有图片
- (NSArray<PHAsset *> *)getAssetsInAssetCollection:(PHAssetCollection *)assetCollection ascending:(BOOL)ascending
{
    NSMutableArray<PHAsset *> *arr = [NSMutableArray array];

    PHFetchResult *result = [self fetchAssetsInAssetCollection:assetCollection ascending:ascending];
    [result enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        [arr addObject:obj];//这个obj即PHAsset对象
    }];
    return arr;
}

8.验证该图片是否在本地（若开启了iCloud照片存储，则图片会定时上传到网上，本地不存在）

PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];
    option.networkAccessAllowed = NO;
    option.synchronous = YES;

    __block BOOL isInLocalAblum = YES;

    [[PHCachingImageManager defaultManager] requestImageDataForAsset:asset options:option resultHandler:^(NSData * _Nullable imageData, NSString * _Nullable dataUTI, UIImageOrientation orientation, NSDictionary * _Nullable info) {
        isInLocalAblum = imageData ? YES : NO;
    }];
    return isInLocalAblum;

9.获取LivePhoto

PHLivePhotoRequestOptions *option = [[PHLivePhotoRequestOptions alloc] init];
    option.version = PHImageRequestOptionsVersionCurrent;
    option.deliveryMode = PHImageRequestOptionsDeliveryModeOpportunistic;
    option.networkAccessAllowed = YES;

    [[PHCachingImageManager defaultManager] requestLivePhotoForAsset:asset targetSize:PHImageManagerMaximumSize contentMode:PHImageContentModeAspectFit options:option resultHandler:^(PHLivePhoto * _Nullable livePhoto, NSDictionary * _Nullable info) {
        if (completion) completion(livePhoto, info);
    }];

10.获取Video

[[PHCachingImageManager defaultManager] requestPlayerItemForVideo:asset options:nil resultHandler:^(AVPlayerItem * _Nullable playerItem, NSDictionary * _Nullable info) {
        if (completion) completion(playerItem, info);
    }];