保存图片到相簿中

作者: 打电话记错号码的人 | 来源:发表于2016-10-03 09:17 被阅读91次

    作品链接:
    http://www.jianshu.com/users/1e0f5e6f73f6/top_articles

    • 需要导入第三方框架
    #import <Photos/Photos.h>
    #import <SVProgressHUD.h>
    

    1.设置用户访问相簿的权限

    - (IBAction)save {
        
        /*
         PHAuthorizationStatusNotDetermined,     用户还没有做出选择
         PHAuthorizationStatusDenied,            用户拒绝当前应用访问相册(用户当初点击了"不允许")
         PHAuthorizationStatusAuthorized         用户允许当前应用访问相册(用户当初点击了"好")
         PHAuthorizationStatusRestricted,        因为家长控制, 导致应用无法方法相册(跟用户的选择没有关系)
         */
    
        // 判断授权状态
        PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
        
        if (status == PHAuthorizationStatusRestricted) {
            [SVProgressHUD showErrorWithStatus:@"因为系统原因,无法访问相册"];
        } else if (status == PHAuthorizationStatusDenied){
            // 用户拒绝当前应用访问相册(用户当初点击了"不允许")
            PHLog(@"提醒用户去[设置-隐私-照片-xxx]打开访问开关");
        } else if (status == PHAuthorizationStatusAuthorized){
            //用户允许当前应用访问相册  用户当初点击了好
            [self saveImage];
        } else if (status == PHAuthorizationStatusNotDetermined){
            
            // 用户还没有做出选择
            // 弹框请求用户授权
            [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
                if (status == PHAuthorizationStatusAuthorized) {
                    [self saveImage];
                }
            }];
         }
    }
    

    2.保护图片

    - (void)saveImage
    {
        // PHAsset : 一个资源, 比如一张图片\一段视频
        // PHAssetCollection : 一个相簿
        
        // PHAssetCollection的标识,利用这个标识可以找到对应的PHAssetCollection的对象(相簿对象)
        __block NSString *assetCollectionLocalIdentifier = nil;
        __block NSString *assetLocalIdentifier = nil;
        // PHAsset的标识,利用这个标识可以找到对应的PHAsset对象 即图片对象
        
        // 如果想对"相册"进行修改(增删改), 那么修改代码必须放在[PHPhotoLibrary sharedPhotoLibrary]的performChanges方法的block中
        [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
            //1.保存图片A到【相机胶卷】中
            // 创建图片的请求
            assetLocalIdentifier = [PHAssetCreationRequest creationRequestForAssetFromImage:self.imageView.image].placeholderForCreatedAsset.localIdentifier;
            
        } completionHandler:^(BOOL success, NSError * _Nullable error) {
            if (success == NO) {
                PHLog(@"保存【图片】到【相机胶卷】中失败!失败信息-%@",error);
                return ;
            }
            
            // 获得曾经创建过的相簿
            PHAssetCollection *createdAssetCollection = [self createdAssetCollection];
            if (createdAssetCollection) {
                // 3.添加【相机胶卷】中的图片A到【相簿】D中
               [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                    // 获得图片
                   PHAsset *asset = [PHAsset fetchAssetsWithLocalIdentifiers:@[assetLocalIdentifier] options:nil].lastObject;
                   // 图片添加到相簿中的请求
                   PHAssetCollectionChangeRequest *request = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:createdAssetCollection];
                   // 添加图片到相簿
                   [request addAssets:@[asset]];
                   
               } completionHandler:^(BOOL success, NSError * _Nullable error) {
                   if (success == NO) {
                       PHLog(@"添加[图片]到[相簿]失败!失败信息-%@",error);
                   } else{
                       PHLog(@"成功添加[图片]到[相簿]!");
                   }
               }];
               
            } else{
                // 没有创建过相簿
                [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                    //2.创建"相簿"D
                    // 创建相簿的请求
                    
                    assetCollectionLocalIdentifier = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:PPHAssetCollectionTitle].placeholderForCreatedAssetCollection.localIdentifier;
                    
                } completionHandler:^(BOOL success, NSError * _Nullable error) {
                    if (!success) {
                        PHLog(@"保存相簿失败!失败信息-%@",error);
                        return ;
                    }
                    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                        // 3.添加"相机胶卷"中的图片A到新建的"相簿"D中
                        
                        // 获得相簿
                        PHAssetCollection *assetCollection = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[assetCollectionLocalIdentifier] options:nil].lastObject;
                        // 获得图片
                        PHAsset *asset = [PHAsset fetchAssetsWithLocalIdentifiers:@[assetLocalIdentifier] options:nil].lastObject;
                        
                        // 添加图片到相簿中的请求
                        PHAssetCollectionChangeRequest *request = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:assetCollection];
                        
                        // 添加图片到相簿
                        [request addAssets:@[asset]];
                    } completionHandler:^(BOOL success, NSError * _Nullable error) {
                        if (success == NO) {
                            PHLog(@"添加[图片]到[相簿]失败!失败信息-%@",error);
                        } else{
                            PHLog(@"成功添加[图片]到[相簿]!");
                        }
                    }];
                }];
            }
        }];
    }
    

    3.创建相册

    - (PHAssetCollection *)createdAssetCollection
    {
        PHFetchResult<PHAssetCollection *> *assetCollections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
        
        for (PHAssetCollection *assetCollection in assetCollections) {
            if ([assetCollection.localizedTitle isEqualToString:PPHAssetCollectionTitle]) {
                return assetCollection;
            }
        }
        return nil;
    }
    

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