iphone - AVCamDemo：completionHandler 代码未命中

Question

我正在简化AVCamDemo项目，以便我可以尝试仅捕获静止图像。

下面是captureStillImage()方法的新代码：

- (void) captureStillImage
{
    AVCaptureConnection *stillImageConnection = [AVCamUtilities connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]];
    if ([stillImageConnection isVideoOrientationSupported]) {
        [stillImageConnection setVideoOrientation:orientation];
    }
    [[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:stillImageConnection
                completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
NSLog(@"In the completionHandler block");
           if (imageDataSampleBuffer != NULL) {
               NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
               UIImage *image = [[UIImage alloc] initWithData:imageData];
                     [self writeImageFile:image];
                     [image release];
            }
          if ([[self delegate] respondsToSelector:@selector(captureManagerStillImageCaptured:)]) {
               [[self delegate] captureManagerStillImageCaptured:self];
                }
     }];
NSLog(@"exiting....");
}

在我的测试中，我发现有时，块中的 NSLog 语句没有被执行......因此 stillImage文件没有得到保存。

我遇到时间问题了吗？如果是这样，我该如何解决它们？

谢谢并恭祝安康。山姆。