SBPFMLMainActivity.kt

class MainActivity : AppCompatActivity() {

    private lateinit var fotoapparat: Fotoapparat
    private lateinit var barcodeScanner: BarcodeScanner

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        initializeBarcodeScanner()

        initializeFotoapparat()

        button.setOnClickListener {
            if (isCameraPermissionGranted())
                takeImage()
            else requestCameraPermission()
        }

        if (!isCameraPermissionGranted()) requestCameraPermission()
    }

    private fun takeImage() {
        fotoapparat.takePicture().toBitmap().whenAvailable {
            scanImageForBarcode(it!!)
        }
    }

    private fun scanImageForBarcode(it: BitmapPhoto) {
        val inputImage = InputImage.fromBitmap(it.bitmap, it.rotationDegrees)
        val task = barcodeScanner.process(inputImage)
        task.addOnSuccessListener { barCodesList ->
            for (barcodeObject in barCodesList) {
                val barcodeValue = barcodeObject.rawValue
                textView.text = barcodeValue
                Log.d("Barcode", "The code %s".format(barcodeValue))
            }
        }
        task.addOnFailureListener {
            Log.d("ERROR", "An Exception occurred", it)
        }
    }

    private fun initializeFotoapparat() {
        fotoapparat = Fotoapparat.with(this)
            .into(cameraView)
            .previewScaleType(ScaleType.CenterCrop)
            .build()
    }

    private fun initializeBarcodeScanner() {
        val options = BarcodeScannerOptions.Builder()
            .setBarcodeFormats(
                Barcode.FORMAT_EAN_13,
                Barcode.FORMAT_QR_CODE
            )
            .build()

        barcodeScanner = BarcodeScanning.getClient(options)
    }

    override fun onStart() {
        super.onStart()
        fotoapparat.start()
    }

    override fun onStop() {
        super.onStop()
        fotoapparat.stop()
    }

    private fun isCameraPermissionGranted(): Boolean {
        return (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                == PackageManager.PERMISSION_GRANTED)
    }

    private fun requestCameraPermission() {
        ActivityCompat.requestPermissions(
            this,
            arrayOf(Manifest.permission.CAMERA),
            1144
        )
    }
}