我想,出于安全考虑,键盘可能会有一些限制？

1.打开火炬

-(void) turnFlashOn
{
    AVCaptureDevice *flashLight = [AVCaptureDevice
                                   defaultDeviceWithMediaType:AVMediaTypeVideo];
    if([flashLight isTorchAvailable] && [flashLight
                                         isTorchModeSupported:AVCaptureTorchModeOn])
    {
        BOOL success = [flashLight lockForConfiguration:nil];
        if(success){
            NSError *error;
            [flashLight setTorchMode:AVCaptureTorchModeOn];
            [flashLight setTorchModeOnWithLevel:1.0 error:&error];
            NSLog(@"Error: %@",error);
            [flashLight unlockForConfiguration];
            NSLog(@"flash turned on -> OK");

        }
        else
        {
            NSLog(@"flash turn on -> ERROR");
        }
    }

}

这给我这个日志输出,但闪光灯没有任何反应：

Error: (null)
flash turned on -> OK

2.)扫描条形码(viewDidLoad的一部分)

// SCANNER PART
self.captureSession = [[AVCaptureSession alloc] init];
AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];
if(videoInput)
    [self.captureSession addInput:videoInput];
else
    NSLog(@"Error: %@",error);

AVCaptureMetadataOutput *MetadataOutput = [[AVCaptureMetadataOutput alloc] init];
[self.captureSession addOutput:MetadataOutput];
[MetadataOutput setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[MetadataOutput setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code]];

AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];

camView = [[UIView alloc] initWithFrame: [[UIScreen mainScreen] bounds]];
previewLayer.frame = camView.layer.bounds;
[camView.layer addSublayer:previewLayer];
self.keyboard.barcodeView.clipsToBounds=YES;
camView.center = CGPointMake(self.keyboard.barcodeView.frame.size.width/2,self.keyboard.barcodeView.frame.size.height/2);

[self.keyboard.barcodeView addSubview:camView];

如果我在我的键盘上按一个特殊的键,这个叫做：

-(void)scanBarcodeNow{
AudioServicesPlaySystemSound(systemSoundTock);
NSLog(@"Start scanning...");
self.keyboard.barcodeView.hidden=false;
[self.keyboard.barcodeView addSubview:camView];
[self.keyboard.barcodeView setBackgroundColor:[UIColor redColor]];
[self.captureSession startRunning];

}

唯一的事情是,keyboard.barcodeView将其背景颜色更改为红色.我已经看到,我所做的所有接线应该是好的.但是没有显示凸轮的视频….

谁能帮我吗？