objective-c - 如何在 iOS 中获取照片的原始文件名？

Question

我目前正在开发一个 iPad 应用程序，用户可以在其中的文本字段中输入照片文件名(作为字段注释的一部分)，然后他们会将照片导入 iPad 的照片库。该应用程序将使用 ALAssetsLibrary 访问图书馆并枚举照片，寻找具有他们在现场笔记中输入的文件名的照片。这将是拍摄照片的相机赋予照片的文件名。例如“DSC_0019.JPG”。

这不可能吗？

我注意到，如果我将照片从我的相机导入 iPad，然后在我的 Mac 上打开 iPhoto 并将 iPad 视为相机，我可以“获取 iPad 上保存的图像的信息”并查看原始文件名 I正在寻找。然而，这不包含在 iPad 上的元数据中。

如有任何帮助，我们将不胜感激。

这是我的代码:

(在使用 CFDictionary 时，几乎所有内容都是空的，除了没有我要找的内容的 Exif 键)

- (void)viewDidLoad
{
    [super viewDidLoad];

    //start activity animation
    [self.activity setHidden:NO];
    [self.activity startAnimating];

    //init our arrays
    autoAssignedAssets  = [[NSMutableArray alloc] init];
    unAssignedRecords   = [[NSMutableArray alloc] init];
    unAssignedAssets    = [[NSMutableArray alloc] init];

    //setup the library
    ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];



    //[ BLOCK ] => assetEnumerator
    //
    void (^assetEnumerator)(ALAsset *, NSUInteger, BOOL *) = ^(ALAsset *result, NSUInteger index, BOOL *stop) {

        if (result != nil) {

            if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto] ) {


                //=================================================================

                ALAssetRepresentation* representation = [result defaultRepresentation];

                // create a buffer to hold the data for the asset's image
                uint8_t *buffer = (Byte*)malloc(representation.size);// copy the data from the asset into the buffer
                NSUInteger length = [representation getBytes:buffer fromOffset: 0.0  length:representation.size error:nil];

                // convert the buffer into a NSData object, free the buffer after
                NSData *adata = [[NSData alloc] initWithBytesNoCopy:buffer length:representation.size freeWhenDone:YES];

                // setup a dictionary with a UTI hint.  The UTI hint identifies the type of image we are dealing with (ie. a jpeg, png, or a possible RAW file)
                // specify the source hint
                NSDictionary* sourceOptionsDict = [NSDictionary dictionaryWithObjectsAndKeys: (id)[representation UTI] ,kCGImageSourceTypeIdentifierHint, nil];


                // create a CGImageSource with the NSData.  A image source can contain x number of thumbnails and full images.
                CGImageSourceRef sourceRef = CGImageSourceCreateWithData((CFDataRef) adata,  (CFDictionaryRef) sourceOptionsDict);

                [adata release];

                CFDictionaryRef imagePropertiesDictionary;

                // get a copy of the image properties from the CGImageSourceRef
                imagePropertiesDictionary = CGImageSourceCopyPropertiesAtIndex(sourceRef,0, NULL);

                //NSString *imageFilename = (NSString*)CFDictionaryGetValue(imagePropertiesDictionary, kCGImagePropertyCIFFImageFileName);

                NSLog(@"%@", (NSDictionary *)CFDictionaryGetValue(imagePropertiesDictionary, kCGImagePropertyExifDictionary));

                CFNumberRef imageWidth = (CFNumberRef)CFDictionaryGetValue(imagePropertiesDictionary, kCGImagePropertyPixelWidth);
                CFNumberRef imageHeight = (CFNumberRef)CFDictionaryGetValue(imagePropertiesDictionary, kCGImagePropertyPixelHeight);

                int w = 0;
                int h = 0;

                CFNumberGetValue(imageWidth, kCFNumberIntType, &w);
                CFNumberGetValue(imageHeight, kCFNumberIntType, &h);

                // cleanup memory
                CFRelease(imagePropertiesDictionary);
                CFRelease(sourceRef);

                //NSLog(@"width: %d, height: %d", w, h);
                //NSLog(@"%@", imageFilename);



                //=================================================================


                //NSDictionary *metadata = [[result defaultRepresentation] metadata];
                //NSLog(@"\n\nAsset Info: %@", result);
                //NSLog(@"\n\n\n\nMetaData: %@", metadata);
                [autoAssignedAssets addObject:result];

            }//end if photo

        }//end if

    }; //end assetEnumerator block



    //[ BLOCK ] => assetGroupEnumerator
    //
    void (^assetGroupEnumerator)(ALAssetsGroup *, BOOL *) =  ^(ALAssetsGroup *group, BOOL *stop) {

        if(group != nil) {
            [group enumerateAssetsUsingBlock:assetEnumerator];
        }//end if


        //now we're done, reload and stop animations
        [self.tableView reloadData];
        [self.activity stopAnimating];
        [self.activity setHidden:YES];

    }; //end assetGroupEnumerator block



    //[ BLOCK ] => failureBlock
    //
    void (^failureBlock)(NSError *) = ^(NSError *error) {

        NSString *errorTitle = [error localizedDescription];
        NSString *errorMessage = [error localizedRecoverySuggestion];
        NSString *errorFailureDesc = [error localizedFailureReason];

        NSLog(@"Error: %@, Suggestion: %@, Failure desc: %@", errorTitle, errorMessage, errorFailureDesc);

    }; //end failureBlock




    //loop over all the albums and process the pictures with the blocks above
    [library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:assetGroupEnumerator failureBlock: failureBlock];


}//end viewDidLoad

Answer 1

我能够像这样获取图像的原始文件名:

NSString* originalFileName = [[asset defaultRepresentation] filename];