Question

我想在条形码扫描仪中添加导航栏。通过这种方式，我可以关闭条形码扫描仪（模态）视图，但由于导航栏不在此处，因此无法正常工作。

这些是我的setupNavBar方法和我的navBar来设置我的navigationBar：

let navBar: UINavigationBar = {
        let bar = UINavigationBar()
        bar.translatesAutoresizingMaskIntoConstraints = false
        return bar
    }()

    func setupNavBar(){

        view.addSubview(navBar)
        view.bringSubview(toFront: navBar)

        navBar.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.09).isActive = true
        navBar.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
        navBar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        navBar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        navBar.topAnchor.constraint(equalTo: view.topAnchor).isActive = true

        let doneItem = UIBarButtonItem(title:"Cancel",style: .done, target: nil, action: #selector(doneButton));
        let navItem = UINavigationItem(title: "Scanner");
        navItem.rightBarButtonItem = doneItem;
        navBar.setItems([navItem], animated: false);

    }


func doneButton(){

    let presentingViewController: UIViewController! = self.presentingViewController
    presentingViewController.presentingViewController!.dismiss(animated: true, completion: nil)

}

下面是我的扫描仪代码：

    var captureSession: AVCaptureSession!
    var previewLayer: AVCaptureVideoPreviewLayer!


    override func viewDidLoad() {
        super.viewDidLoad()

        setupNavBar()
        view.backgroundColor = UIColor.black
        captureSession = AVCaptureSession()

        let videoCaptureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
        let videoInput: AVCaptureDeviceInput

        do {
            videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice)
        } catch {
            return
        }

        if (captureSession.canAddInput(videoInput)) {
            captureSession.addInput(videoInput)
        } else {
            failed();
            return;
        }

        let metadataOutput = AVCaptureMetadataOutput()

        if (captureSession.canAddOutput(metadataOutput)) {
            captureSession.addOutput(metadataOutput)

            metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
            metadataOutput.metadataObjectTypes = [AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypePDF417Code]
        } else {
            failed()
            return
        }

        previewLayer = AVCaptureVideoPreviewLayer(session: captureSession);
        previewLayer.frame = view.layer.bounds;
        previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
        view.layer.addSublayer(previewLayer);



        captureSession.startRunning();
    }

    func failed() {
        let ac = UIAlertController(title: "Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.", preferredStyle: .alert)
        ac.addAction(UIAlertAction(title: "OK", style: .default))
        present(ac, animated: true)
        captureSession = nil
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        if (captureSession?.isRunning == false) {
            captureSession.startRunning();
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        if (captureSession?.isRunning == true) {
            captureSession.stopRunning();
        }
    }

    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
        captureSession.stopRunning()

        if let metadataObject = metadataObjects.first {
            let readableObject = metadataObject as! AVMetadataMachineReadableCodeObject;

            AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
            found(code: readableObject.stringValue);

            self.isbn = readableObject.stringValue
            self.performSegue(withIdentifier: "scanToSell", sender: nil)
        }

    }

    func found(code: String) {
        print(code)
    }

    override var prefersStatusBarHidden: Bool {
        return true
    }

    override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
        return .portrait
    }

提前谢谢你。干得好

Answer 1

前几天我遇到了同样的问题。我创建了一个scannerviewcontroller。检查一下：https://gist.github.com/Raghvendra7/ff6335c47bbca04fb88d1cb76917d2e5，它解决了取消问题。希望它会有所帮助。在此控制器中处理扫描仪效果，并在完成时更新。

Answer 2

我发现了我的错误。在我的viewDidLoad方法中，setupNavBar必须以这种方式改变位置。

 override func viewDidLoad() {
    super.viewDidLoad()

  //  setupNavBar() No
    view.backgroundColor = UIColor.black
    captureSession = AVCaptureSession()

    let videoCaptureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
    let videoInput: AVCaptureDeviceInput

        do {
            videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice)
        } catch {
            return
        }

        if (captureSession.canAddInput(videoInput)) {
            captureSession.addInput(videoInput)
        } else {
            failed();
            return;
        }

        let metadataOutput = AVCaptureMetadataOutput()

        if (captureSession.canAddOutput(metadataOutput)) {
            captureSession.addOutput(metadataOutput)

            metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
            metadataOutput.metadataObjectTypes = [AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypePDF417Code]
        } else {
            failed()
            return
        }

        previewLayer = AVCaptureVideoPreviewLayer(session: captureSession);
        previewLayer.frame = view.layer.bounds;
        previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
        view.layer.addSublayer(previewLayer);

  setupNavBar() // Yes

        captureSession.startRunning();
    }

扫描仪视图中的导航栏 - IOS - Swift

2 个答案: