AVCaptureStillImageOutput에서 마지막으로 캡쳐 한 이미지 미리보기

Question

AVCaptureSession을 사용하여 내 iOS 앱에서 이미지를 캡처하고 싶습니다. Apple의 AVCam 샘플 코드 https://developer.apple.com/library/ios/samplecode/AVCam/Introduction/Intro.html을 기반으로 이미지를 캡처 할 때마다 미리보기 ImageView를 표시하려고했습니다. processImage를 캡처 한 후

// Capture a still image. 
    [[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:[[self stillImageOutput] connectionWithMediaType:AVMediaTypeVideo] completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) { 

     if (imageDataSampleBuffer) 
     { 
      NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer]; 
      [self processImage:[UIImage imageWithData:imageData]]; 
     } 
    }]; 

는

- (void) processImage:(UIImage *)image 
{ 
    [[self postButton] setEnabled:YES]; 
    [[self postButton] setHidden:NO]; 
    [[self cancelButton] setEnabled:YES]; 
    [[self cancelButton] setHidden:NO]; 

    _preview = [[UIImageView alloc] init]; 
    [_preview setImage:image]; 

    _preview.hidden = NO; 
} 

라고하지만가 표시 될 때 이미지 뷰가 비어/아직 변경되지 않습니다.

누군가 나를 따라갈 수 있습니까? 나를

AVCaptureConnection *connection = [_currentOutput connectionWithMediaType:AVMediaTypeVideo]; 
[self _setOrientationForConnection:connection]; 

[_captureOutputPhoto captureStillImageAsynchronouslyFromConnection:connection completionHandler: 
^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) { 

    if (!imageDataSampleBuffer) { 
     DLog(@"failed to obtain image data sample buffer"); 
     // return delegate error 
     return; 
    } 

    if (error) { 
     if ([_delegate respondsToSelector:@selector(vision:capturedPhoto:error:)]) { 
      [_delegate vision:self capturedPhoto:nil error:error]; 
     } 
     return; 
    } 

    NSMutableDictionary *photoDict = [[NSMutableDictionary alloc] init]; 
    NSDictionary *metadata = nil; 

    // add photo metadata (ie EXIF: Aperture, Brightness, Exposure, FocalLength, etc) 
    metadata = (__bridge NSDictionary *)CMCopyDictionaryOfAttachments(kCFAllocatorDefault, imageDataSampleBuffer, kCMAttachmentMode_ShouldPropagate); 
    if (metadata) { 
     [photoDict setObject:metadata forKey:PBJVisionPhotoMetadataKey]; 
     CFRelease((__bridge CFTypeRef)(metadata)); 
    } else { 
     DLog(@"failed to generate metadata for photo"); 
    } 

    // add JPEG and image data 
    NSData *jpegData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer]; 
    if (jpegData) { 
     // add JPEG 
     [photoDict setObject:jpegData forKey:PBJVisionPhotoJPEGKey]; 

     // add image 
     UIImage *image = [self _uiimageFromJPEGData:jpegData]; 
     if (image) { 
      [photoDict setObject:image forKey:PBJVisionPhotoImageKey]; 
     } else { 
      DLog(@"failed to create image from JPEG"); 
      // TODO: return delegate on error 
     } 

     // add thumbnail 
     UIImage *thumbnail = [self _thumbnailJPEGData:jpegData]; 
     if (thumbnail) { 
      [photoDict setObject:thumbnail forKey:PBJVisionPhotoThumbnailKey]; 
     } else { 
      DLog(@"failed to create a thumnbail"); 
      // TODO: return delegate on error 
     } 

    } else { 
     DLog(@"failed to create jpeg still image data"); 
     // TODO: return delegate on error 
    } 

    if ([_delegate respondsToSelector:@selector(vision:capturedPhoto:error:)]) { 
     [_delegate vision:self capturedPhoto:photoDict error:error]; 
    } 

    // run a post shot focus 
    [self performSelector:@selector(_focus) withObject:nil afterDelay:0.5f]; 
}]; 

Answer 1

이 코드는 작동합니다. 전화를 메인 스레드로 재발송하십시오.

dispatch_async(dispatch_get_main_queue(), ^{ 
    [self processImage:[UIImage imageWithData:imageData]]; 
}); 

_preview를 결코 하위보기로 추가하지 않습니다.

Answer 2

나는 문제가 여기 captureStillImageAsynchronouslyFromConnection에 대한 completionHandler 메인 스레드에서 호출되지 않을 것입니다 내기 위해