如何将图像从资产库移动到特定于应用程序的私有位置？ [英] How to move an image from asset library to an application specific private location?

问题描述

以下是我尝试的代码段：

Here is the code snippet i tried:

[library    writeImageToSavedPhotosAlbum:self.checkInImage.CGImage metadata:self.metadata
            completionBlock             :^(NSURL * assetURL, NSError * error) {
        NSLog (@"Asset url = %@", assetURL);
         NSError *err;
        NSString *docDir = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
        NSString *jpgFilePath = [NSString stringWithFormat:@"%@/test.jpg", docDir];
        NSFileManager *fileManager = [NSFileManager defaultManager];
                [fileManager moveItemAtURL:assetURL toURL:[NSURL URLWithString:jpgFilePath] error:&err];
                NSLog(@"error is %@", err);
    }];

我收到错误
错误域= NSCocoaErrorDomain代码= 262操作无法'完成。（可可错误262.）UserInfo = 0xb49a680 {NSURL = assets-library：//asset/asset.JPG？id = 6FAC823A-33CB-489B-A125-714FBA5F0EE8& ext = JPG}

I get the error as Error Domain=NSCocoaErrorDomain Code=262 "The operation couldn’t be completed. (Cocoa error 262.)" UserInfo=0xb49a680 {NSURL=assets-library://asset/asset.JPG?id=6FAC823A-33CB-489B-A125-714FBA5F0EE8&ext=JPG}

任何想法？

推荐答案

这就是我解决问题的方法：

This is how I solved the issue:

1）我在某个位置保存了没有元数据的文件，并存储了其urlpath。

1) I saved the file without metadata in some location, and stored its urlpath.

2）然后使用下面的一块使用元数据保存同一文件的代码。这里fileURL是从步骤1获得的urlpath。

2) Then used the following piece of code to save the same file with metadata. Here fileURL is the urlpath obtained from step 1.

CFURLRef url = CFURLCreateFilePathURL(NULL, (CFURLRef)fileURL, NULL);
// Creating Image source from image url
CGImageSourceRef imageSource = CGImageSourceCreateWithURL(url, NULL);

// This will be the data CGImageDestinationRef will write into
CFMutableDataRef data = CFDataCreateMutable(kCFAllocatorDefault, 0);
CGImageDestinationRef imageDestination = CGImageDestinationCreateWithData(data, CFSTR("public.jpeg"), 1, NULL);

BOOL success = (imageSource != NULL);

require(success, cleanup);

success = (imageDestination != NULL);
require(success, cleanup);

// Add the image contained in the image source to the destination, overidding the old metadata with our modified metadata
NSDictionary *metadata = someObj.metadata;
CGImageDestinationAddImageFromSource(imageDestination, imageSource, 0, (CFDictionaryRef)metadata);

// Tell the destination to write the image data and metadata into our data object.
success = CGImageDestinationFinalize(imageDestination);

require(success, cleanup);

// Write the data into the url
[(NSMutableData *) data writeToURL:fileURL atomically:YES];

清理：

if (data) {
    CFRelease(data);
    data = NULL;
}

if (imageSource) {
    CFRelease(imageSource);
    imageSource = NULL;
}

if (imageDestination) {
    CFRelease(imageDestination);
    imageDestination = NULL;
}

return success;

希望这会有所帮助。但我想提出H2C03的非常有用的建议，这有助于达成这个解决方案。请帮我怎么做。谢谢。

Hope this helps. But I would like to upvote H2C03 for very helpful suggestions, which helped to arrive at this solution. Please help me how to do it. Thanks.

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