使用AVCam打开/关闭闪光灯

Question

我正在使用Apple的AVCam源代码创建自定义相机，我正在尝试打开/关闭闪光灯，但它不起作用。这是我的代码，不确定出了什么问题。我是AVCam的新手。

- (void) toggleFlash:(id)sender {
    dispatch_async([self sessionQueue], ^{
        AVCaptureDevice *currentVideoDevice = [[self videoDeviceInput] device];
        AVCaptureDevicePosition currentPosition = [currentVideoDevice position];
        if(currentPosition == AVCaptureDevicePositionUnspecified || currentPosition == AVCaptureDevicePositionBack) {
            if([currentVideoDevice hasFlash]) {
                [currentVideoDevice lockForConfiguration:nil];
                [currentVideoDevice setFlashMode:AVCaptureFlashModeOn];
                [currentVideoDevice unlockForConfiguration];
            }
        }
    });
}

它在代码中遍历每一行，并且不会记录任何错误，但仍然没有运气。

Answer 1

- (void) toggleFlash {
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if ([device hasTorch] && [device hasFlash]){
        [device lockForConfiguration:nil];
        [device setTorchMode:!device.torchActive];
        [device setFlashMode:!device.torchActive];
        [device unlockForConfiguration];
    }
}

附言就我而言，手电筒/闪光灯最初是关闭的。