需要帮助完成Kotlin中Firebase QR码扫描器的活动。

Question

我正试图为我的公司创建一个二维码扫描器，以便在生产过程中扫描使用过的零件上的二维码。我目前的功能是扫描代码并更新主活动上的文本视图，但扫描后，我必须手动点击后退按钮才能回到主活动。此外，最终版本需要将扫描结果添加到列表中，而不是文本视图，所以我需要它只扫描一次。我试图让扫描器在处理完代码后就结束活动，但由于某些原因，finish()函数没有工作。

class ScanActivity : AppCompatActivity() {

    lateinit var scanView: TextureView

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

        scanView = findViewById(R.id.scanView)
        scanView.addOnLayoutChangeListener { _, _, _, _, _, _, _, _, _ ->
            updateTransform()
        }
        if (allPermissionsGranted()) {
            scanView.post { startCamera() }

        } else {
            ActivityCompat.requestPermissions(
                    this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS)
        }
    }

    private fun startCamera() {
        val previewConfig = PreviewConfig.Builder().apply {
            setTargetResolution(Size(800, 640))
        }.build()

        val preview = Preview(previewConfig)
        preview.setOnPreviewOutputUpdateListener {

            val parent = scanView.parent as ViewGroup
            parent.removeView(scanView)
            parent.addView(scanView, 0)
            scanView.surfaceTexture = it.surfaceTexture
            updateTransform()
        }

        val analyzerConfig = ImageAnalysisConfig.Builder().apply {
            setImageReaderMode(
                    ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE)
        }.build()

        val analyzerUseCase = ImageAnalysis(analyzerConfig).apply {
            setAnalyzer(executor,QRCodeAnalyzer())
        }

        CameraX.bindToLifecycle(this, preview,analyzerUseCase)
    }

    private fun updateTransform() {
        val matrix = Matrix()
        val centerX = scanView.width / 2f
        val centerY = scanView.height / 2f
        val rotationDegrees = when (scanView.display.rotation) {
            Surface.ROTATION_0 -> 0
            Surface.ROTATION_90 -> 90
            Surface.ROTATION_180 -> 180
            Surface.ROTATION_270 -> 270
            else -> return
        }
        matrix.postRotate(-rotationDegrees.toFloat(), centerX, centerY)
        scanView.setTransform(matrix)
    }

    private val executor = Executors.newSingleThreadExecutor()
    private fun allPermissionsGranted() = REQUIRED_PERMISSIONS.all {
        ContextCompat.checkSelfPermission(
                baseContext, it) == PackageManager.PERMISSION_GRANTED
    }

    override fun onRequestPermissionsResult(
            requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
        if (requestCode == REQUEST_CODE_PERMISSIONS) {
            if (allPermissionsGranted()) {
                scanView.post { startCamera() }
            } else {
                Toast.makeText(this,
                        "Permissions not granted by the user.",
                        Toast.LENGTH_SHORT).show()
                finish()
            }
        }
    }

   private class QRCodeAnalyzer : ImageAnalysis.Analyzer {

        private fun degreesToFirebaseRotation(degrees: Int): Int = when (degrees) {
            0 -> FirebaseVisionImageMetadata.ROTATION_0
            90 -> FirebaseVisionImageMetadata.ROTATION_90
            180 -> FirebaseVisionImageMetadata.ROTATION_180
            270 -> FirebaseVisionImageMetadata.ROTATION_270
            else -> throw Exception("Rotation must be 0, 90, 180, or 270.")
        }

        @SuppressLint("SetTextI18n")
        override fun analyze(imageProxy: ImageProxy?, degrees: Int) {

            val mediaImage = imageProxy?.image
            val imageRotation = degreesToFirebaseRotation(degrees)
            if (mediaImage!=null) {
                val image = FirebaseVisionImage.fromMediaImage(mediaImage, imageRotation)
                val options = FirebaseVisionBarcodeDetectorOptions.Builder()
                        .setBarcodeFormats(FirebaseVisionBarcode.FORMAT_QR_CODE).build()
                val detector = FirebaseVision.getInstance().getVisionBarcodeDetector(options)
                val result = detector.detectInImage(image)
                        .addOnSuccessListener { barcodes ->
                            var code = ""
                            for (barcode in barcodes) {
                                code = barcode.rawValue.toString()
                            }
                            Log.i("STAGE ONE COMPLETE!!!", code)

                            //Start breaking down QR scan into Part Number and Lot Number

                            var partNumberText = ""
                            var partNumber: Pattern = Pattern.compile("MCU-(.*?) ")
                            var mPN: Matcher = partNumber.matcher(code)
                            while (mPN.find()) {
                                partNumberText = mPN.group(1)
                                MainActivity.partNumberTextView.text = "Part Number: $partNumberText"
                            }

                            if (code.length > 47) {
                                var lotNumberSubText = code.substring(0, 47)
                                var lotNumberText = ""
                                var lotNumber: Pattern = Pattern.compile("$lotNumberSubText(.*?) ")
                                var mLN: Matcher = lotNumber.matcher(code)
                                while (mLN.find()) {
                                    lotNumberText = mLN.group(1)
                                    MainActivity.lotNumberTextView.text = "Lot Number: $lotNumberText"
                                }
                            }
                            finish()
                        }
                        .addOnFailureListener {
                            Log.i("FAILURE", "Scan Failed")
                        }
            }
        }
    }
}

错误截图

Answer 1

你可以试试这个。在QRCodeAnalyzer类中添加构造函数。

private class QRCodeAnalyzer constructor(val activity: Activity) : ImageAnalysis.Analyzer 

你可以调用:

activity.finish()

和setAnalyzer:

setAnalyzer(executor,QRCodeAnalyzer(this))