iOS8开发之 PHAsset 保存图片到相册(相机胶卷) 详解二

如何通过Photokit保存图片（带有关于定位GPS的Metadata信息）到相册？

http://segmentfault.com/q/1010000004047993

我通过以下2种方法将有关位置的metadata信息写入照片：

将位置信息写入image,让后调用系统api将图片保存到相册

- (void)writeImageDataToSavedPhotosAlbum:(NSData *)imageData metadata:(NSDictionary *)metadata resultBlock:(PHAssetAssetBoolBlock)resultBlock
{
__block PHObjectPlaceholder *placeholderAsset = nil;
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
UIImage *image = [self imageWithData: imageData metadata:metadata];
[PHAssetChangeRequest creationRequestForAssetFromImage: image];
placeholderAsset = newAssetRequest.placeholderForCreatedAsset;
} completionHandler:^(BOOL success, NSError *error) {
if(success){
PHAsset *asset = [self getAssetFromlocalIdentifier:placeholderAsset.localIdentifier];
completionBlock(asset, YES);
} else {
completionBlock(nil, NO);
}
}];
}

- (UIImage *)imageWithData:(NSData *)imageData metadata:(NSDictionary *)metadata
{
CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
NSMutableDictionary * sourceDic = [NSMutableDictionary dictionary];
NSDictionary *source_metadata = (NSDictionary *)CFBridgingRelease(CGImageSourceCopyProperties(source, NULL));
[sourceDic addEntriesFromDictionary: metadata];
[sourceDic addEntriesFromDictionary:source_metadata];

NSMutableData *dest_data = [NSMutableData data];
CFStringRef UTI = CGImageSourceGetType(source);
CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)dest_data, UTI, 1,NULL);
CGImageDestinationAddImageFromSource(destination, source, 0, (__bridge CFDictionaryRef)sourceDic);
CGImageDestinationFinalize(destination);
CFRelease(source);
CFRelease(destination);
return [UIImage imageWithData: dest_data];
}

2.用PHAssetChangeRequest的location属性保存，代码如下：

+(void)saveImageToCameraRoll:(UIImage*)image location:(CLLocation*)location completionBlock:(PHAssetAssetBoolBlock)completionBlock{
__block PHObjectPlaceholder *placeholderAsset = nil;
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
PHAssetChangeRequest *newAssetRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
newAssetRequest.location = location;
newAssetRequest.creationDate = [NSDate date];
placeholderAsset = newAssetRequest.placeholderForCreatedAsset;
} completionHandler:^(BOOL success, NSError *error) {
if(success){
PHAsset *asset = [self getAssetFromlocalIdentifier:placeholderAsset.localIdentifier];
completionBlock(asset, YES);
} else {
completionBlock(nil, NO);
}
}];
}

然后获取照片的metadata信息，发现没有关于GPS的信息，获取方法如下：

- (void)getPhotoMetadataWithAsset:(PHAsset *)asset
{
PHImageRequestOptions *request = [PHImageRequestOptions new];
request.version = PHImageRequestOptionsVersionCurrent;
request.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat;
request.resizeMode = PHImageRequestOptionsResizeModeNone;
request.synchronous = YES;

[[PHImageManager defaultManager] requestImageDataForAsset:asset options: request resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) {
CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
if (NULL != source) {
NSDictionary * metadataDic = (NSDictionary *)CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(source, 0, NULL));
NSLog(@"metada:%@",metadataDic);
CFRelease(source);
}
}];
}

麻烦看下是保存metadata过程有问题？还是获取metadata有问题？

ios

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1 个回答

答案对人有帮助，有参考价值
0
答案没帮助，是错误的答案，答非所问



littlecode 2 2015年11月26日
回答

找到答案了，补充上。
首先，保存方法按第二种方法保存。获取的话不需要那么麻烦，直接获取asset.location就可以了。

+(void)saveImageToCameraRoll:(UIImage*)image location:(CLLocation*)location completionBlock:(PHAssetAssetBoolBlock)completionBlock{
__block PHObjectPlaceholder *placeholderAsset = nil;
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
PHAssetChangeRequest *newAssetRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
newAssetRequest.location = location;
newAssetRequest.creationDate = [NSDate date];
placeholderAsset = newAssetRequest.placeholderForCreatedAsset;
} completionHandler:^(BOOL success, NSError *error) {
if(success){
PHAsset *asset = [self getAssetFromlocalIdentifier:placeholderAsset.localIdentifier];
CLLocation * location ＝ asset.location;
completionBlock(asset, YES);
} else {
completionBlock(nil, NO);
}
}];
}

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