如何在iOS中获取照片的原始文件名？

我目前正在开发一个iPad应用程序，用户将在文本字段中输入照片文件名（作为现场笔记的一部分），之后他们会将照片导入iPad的照片库。 应用程序将使用ALAssetsLibrary访问库并枚举照片，查找具有在字段注释中输入的文件名的照片。 这将是拍摄它的相机给照片的文件名。 例如“DSC_0019.JPG”。

这不可能吗？

我注意到，如果我将相机中的照片导入iPad，然后在我的Mac上打开iPhoto并将iPad作为相机查看，我可以“获取有关iPad上保存的图像的信息”并查看我正在寻找的原始文件名对于。 但是，这不包含在iPad上的元数据中。

任何帮助将不胜感激。

这是我的代码：

（在使用CFDictionary时，几乎所有东西都是null，除了没有我正在寻找的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

我能够得到一个图像的原始文件名，如下所示： 

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

从ALAsset中提取URL，如下所示：assets-library：//asset/asset.JPG？id = 1000000001＆ext = JPG

如果您需要不同的文件名，请制作内部 – 外部范例： 

 #import  @interface NSURL (NSURL_Asset) - (NSURL*) toExternalForm; - (NSURL*) fromExternalForm; - (NSString*) toExternalFilename; @end #import "NSURL+Asset.h" #import "URLParser.h" // from http://iphone.demay-fr.net/2010/04/parsing-url-parameters-in-a-nsstring/ static NSString *const EXTERNAL_TOKEN = @"/assetExternalForm/"; @implementation NSURL (NSURL_Asset) // assets-library://asset/asset.JPG/assetExternalForm/1000000001.JPG -> assets-library://asset/asset.JPG?id=1000000001&ext=JPG - (NSURL*) fromExternalForm { if([self.scheme isEqualToString:@"assets-library"]) { NSRange slash = [self.absoluteString rangeOfString:EXTERNAL_TOKEN options:NSBackwardsSearch]; if(slash.location != NSNotFound) { NSRange dot = [self.absoluteString rangeOfString:@"." options:NSBackwardsSearch]; if(dot.location != NSNotFound) { NSString* extention = [self.absoluteString substringFromIndex:(dot.location + dot.length)]; NSString* identifier = [self.absoluteString substringWithRange:NSMakeRange(slash.location + slash.length, dot.location - (slash.location + slash.length))]; return [NSURL URLWithString:[NSString stringWithFormat:@"%@?id=%@&ext=%@", [self.absoluteString substringToIndex:slash.location], identifier, extention]]; } } } return self; } // assets-library://asset/asset.JPG?id=1000000001&ext=JPG -> assets-library://asset/asset.JPG/assetExternalForm/1000000001.JPG - (NSURL*) toExternalForm { if([self.scheme isEqualToString:@"assets-library"]) { NSRange range = [self.absoluteString rangeOfString:@"?"]; if(range.location != NSNotFound) { URLParser *parser = [[[URLParser alloc] initWithURLString:self.absoluteString] autorelease]; NSString* extention = [parser valueForVariable:@"ext"]; NSString* identifier = [parser valueForVariable:@"id"]; if(extention != NULL && identifier != NULL) { return [NSURL URLWithString:[NSString stringWithFormat:@"%@%@%@.%@", [self.absoluteString substringToIndex:range.location], EXTERNAL_TOKEN, identifier, extention]]; } } } return self; } // assets-library://asset/asset.JPG?id=1000000001&ext=JPG -> 1000000001.JPG - (NSString*) toExternalFilename { if([self.scheme isEqualToString:@"assets-library"]) { NSRange range = [self.absoluteString rangeOfString:@"?"]; if(range.location != NSNotFound) { URLParser *parser = [[[URLParser alloc] initWithURLString:self.absoluteString] autorelease]; NSString* extention = [parser valueForVariable:@"ext"]; NSString* identifier = [parser valueForVariable:@"id"]; if(extention != NULL && identifier != NULL) { return [NSString stringWithFormat:@"%@.%@", identifier, extention]; } } } return NULL; } @end

请注意，您不需要文件名来读取ALAsset的内容。 使用ALAsset.defaultRepresentation.getBytes方法。

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