iOS 获得图片的时间（通过拍照和取出）

- (void) imagePickerController: (UIImagePickerController *) picker didFinishPickingMediaWithInfo: (NSDictionary *) info {

    

    if(picker.sourceType ==
UIImagePickerControllerSourceTypeCamera) {

        

        //照片mediaInfo

        NSDictionary * imageMetadata = info[@"UIImagePickerControllerMediaMetadata"];

        NSDictionary *tIFFDictionary =  [imageMetadata
objectForKey:(NSString *)kCGImagePropertyTIFFDictionary];

        NSString * pictureTime = tIFFDictionary[@"DateTime"];//2016:01:05 11:45:36

        NSLog(@"pictureDate = %@",pictureTime);

        

    } else
if(picker.sourceType ==
UIImagePickerControllerSourceTypePhotoLibrary){

        NSURL *assetURL = [info
objectForKey:UIImagePickerControllerReferenceURL];

        ALAssetsLibrary *library = [[ALAssetsLibrary
alloc]
init];

        [library assetForURL:assetURL

                 resultBlock:^(ALAsset *asset)  {

                     NSDate* pictureDate = [asset
valueForProperty:ALAssetPropertyDate];

                     NSDateFormatter * formatter = [[NSDateFormatter
alloc]init];

                     formatter.dateFormat =
@"yyyy:MM:dd HH:mm:ss";

                     formatter.timeZone = [NSTimeZone
localTimeZone];

                     NSString * pictureTime = [formatter
stringFromDate:pictureDate];

                     NSLog(@"pictureDate = %@",pictureTime);

                     

                 }

                failureBlock:^(NSError *error) {

        }];

    }

    [picker dismissModalViewControllerAnimated:
NO];

}