How can I recognize barcode with firebase ML Kit?

Question

I am trying to recognize qr code in my app when camera is turned on. And then transfer to according activity depend on qr code text.

I am doing it with firebase ML kit and CameraX library with help of google's documentation but I have errors with ImageAnalyzer's analyze method.

ImageAnalyzer offers me to implement analyze method even though it's already implemented. But it has two parameters: (imageProxy: ImageProxy?, degrees: Int) and says that it overrides nothing. if I delete second parameter (degrees: Int), then it recognizes, but "degrees" is not recognized.

I tried to follow some tutorials but they use lots of third party libraries. I'd like to use cameraX and ML Kit.

How can I fix this?

Here is my code:

package ge.softservice.nfcwithactivties

import android.Manifest
import android.annotation.SuppressLint
import android.content.pm.PackageManager
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.camera.core.*
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import com.google.firebase.ml.vision.FirebaseVision
import com.google.firebase.ml.vision.barcode.FirebaseVisionBarcode
import com.google.firebase.ml.vision.barcode.FirebaseVisionBarcodeDetectorOptions
import com.google.firebase.ml.vision.common.FirebaseVisionImage
import com.google.firebase.ml.vision.common.FirebaseVisionImageMetadata
import kotlinx.android.synthetic.main.activity_qr.*
import java.io.File
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors


class QrActivity : AppCompatActivity() {
    private var preview: Preview? = null
    private var imageAnalyzer: ImageAnalysis? = null
    private var camera: Camera? = null

    internal var isDetected = false

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

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

        // Request camera permissions
        if (allPermissionsGranted()) {
            startCamera()
        } else {
            ActivityCompat.requestPermissions(
                this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS
            )
        }

        //      outputDirectory = getOutputDirectory()

        cameraExecutor = Executors.newSingleThreadExecutor()
    }

    private fun startCamera() {

        val options = FirebaseVisionBarcodeDetectorOptions.Builder()
            .setBarcodeFormats(
                FirebaseVisionBarcode.FORMAT_QR_CODE,
                FirebaseVisionBarcode.FORMAT_AZTEC
            )
            .build()
        val detector = FirebaseVision.getInstance().getVisionBarcodeDetector(options)
        val result = detector.detectInImage(image)
            .addOnSuccessListener { barcodes ->
                // Task completed successfully
                // ...
            }
            .addOnFailureListener {
                // Task failed with an exception
                // ...
            }
        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            // Used to bind the lifecycle of cameras to the lifecycle owner
            val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()

            // Preview
            preview = Preview.Builder()
                .build()

            // Select back camera
            val cameraSelector =
                CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()

            try {
                // Unbind use cases before rebinding
                cameraProvider.unbindAll()

                // Bind use cases to camera
                camera = cameraProvider.bindToLifecycle(
                    this, cameraSelector, preview
                )
                preview?.setSurfaceProvider(viewFinder.createSurfaceProvider(/*camera?.cameraInfo*/))
            } catch (exc: Exception) {
                Log.e(TAG, "Use case binding failed", exc)
            }

        }, ContextCompat.getMainExecutor(this))
    }

    private fun takePhoto() {
        // TODO
    }

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

/*    fun getOutputDirectory(): File {
        val mediaDir = externalMediaDirs.firstOrNull()?.let {
            File(it, resources.getString(R.string.app_name)).apply { mkdirs() } }
        return if (mediaDir != null && mediaDir.exists())
            mediaDir else filesDir
    }*/

    companion object {
        private const val TAG = "CameraXBasic"
        private const val FILENAME_FORMAT = "yyyy-MM-dd-HH-mm-ss-SSS"
        private const val REQUEST_CODE_PERMISSIONS = 10
        private val REQUIRED_PERMISSIONS = arrayOf(Manifest.permission.CAMERA)
    }
}

private class MyImageAnalyzer : 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("UnsafeExperimentalUsageError")
    override fun analyze(imageProxy: ImageProxy?, degrees: Int) {
        val mediaImage = imageProxy?.image
        val imageRotation = degreesToFirebaseRotation(degrees)
        if (mediaImage != null) {
            val image = FirebaseVisionImage.fromMediaImage(mediaImage, imageRotation)
            // Pass image to an ML Kit Vision API
            // ...
        }
    }
}

Answer 1

Looking at your code snippet, it seems you're using camera-camera2 version beta04 with camerax-view version alpha11.

The documentation may be out of date, the Analyzer now only receives an ImageProxy inside its analyze callback. The degrees information that was previously also passed in can now be accessed via ImageProxy.getImageInfo().getRotationDegrees().

So your Analyzer should look like this

private class MyImageAnalyzer : ImageAnalysis.Analyzer {

    private fun degreesToFirebaseRotation(degrees: Int): Int {
        // ...
    }

    override fun analyze(imageProxy: ImageProxy) {
        val mediaImage = imageProxy.image
        val imageRotation = degreesToFirebaseRotation(imageProxy.imageInfo.rotationDegrees)
        val image = FirebaseVisionImage.fromMediaImage(mediaImage, imageRotation)
        // ...
    }
}