启用AR Camera时，iPhone X手电筒关闭

Question

我正在构建一个需要手电筒打开手电筒模式的AR应用程序。打开手电筒模式，然后启用AR场景在我的iPhone 8上工作正常，但在iPhone X上，手电筒打开然后再关闭。有没有办法解决这个问题，或者我需要做些什么来让iPhone X工作？

- (void)turnTorchOn:(bool) on {
    Class captureDeviceClass = NSClassFromString(@"AVCaptureDevice");
    if (captureDeviceClass != nil) {
        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
        if ([device hasTorch]){

            [device lockForConfiguration:nil];
            if (on) {
                [device setTorchMode:AVCaptureTorchModeOn];
            } else {
                [device setTorchMode:AVCaptureTorchModeOff];
            }
            [device unlockForConfiguration];
        }
    }
}

然后是：

self.arConfig = [ARWorldTrackingConfiguration new];
self.arConfig.planeDetection = ARPlaneDetectionHorizontal;
self.sceneView = [[ARSCNView alloc] initWithFrame:self.view.frame];
[self.view addSubview:self.sceneView];

SCNScene *scene = [SCNScene new];
self.sceneView.scene = scene;
self.sceneView.autoenablesDefaultLighting = YES;
self.sceneView.delegate = self;
self.sceneView.session.delegate = self;

更具体地说，这条线关闭了手电筒：

self.sceneView = [[ARSCNView alloc] initWithFrame:self.view.frame];

Answer 1

我希望用Swift编写的代码略有不同（由于guard语句）可能适用于你的iPhone X但老实说，我还没有尝试过。

func toggleTorch(on: Bool) {

    guard let device = AVCaptureDevice.default(for: AVMediaType.video) else { 
        return 
    }
    if device.hasTorch {
        do {
            try device.lockForConfiguration()

            if on == true {
                device.torchMode = .on
            } else {
                device.torchMode = .off
            }

            device.unlockForConfiguration()

        } catch {
            print("Error. Torch couldn't be used")
        }
    } else {
        print("Torch isn't available")
    }
}

// CALL IT:

// toggleTorch(on: true)
// toggleTorch(on: false)

希望这可以帮助。