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Scanning a barcode from an image file with the Android Barcode Scanner SDK

In addition to detecting barcodes from a live camera stream, the Barcode Scanner SDK can scan barcodes from still images imported from the gallery or any other source.

Integration​

For an example of a complete integration of the Android Barcode Scanner, please refer to our scanbot-barcode-scanner-sdk-example-android repository on GitHub.

Adding the feature as a dependency​

To use ScanbotBarcodeDetector, first add the Barcode Scanner SDK as a dependency.

Initializing the SDK​

Before using the Scanbot SDK, it must be initialized.

Processing the image​

To select an image from the photo library and run detection on it, a class for an image import contract is created using the modern Android result API.

class ImportImageContract(private val context: Context) : ActivityResultContract<Unit, Bitmap?>() {
    override fun createIntent(context: Context, input: Unit): Intent {
        // An image is selected from the photo library and document detection is run on it:
        val imageIntent = Intent()
        imageIntent.type = "image/*"
        imageIntent.action = Intent.ACTION_GET_CONTENT
        imageIntent.putExtra(Intent.EXTRA_LOCAL_ONLY, false)
        imageIntent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, false)

       return Intent.createChooser(imageIntent, "Select a picture")
    }

    private fun processGalleryResult(data: Intent): Bitmap? {
        val imageUri = data.data
        return MediaStore.Images.Media.getBitmap(context.contentResolver, imageUri)
    }

    override fun parseResult(resultCode: Int, intent: Intent?): Bitmap? {
       return if (resultCode == Activity.RESULT_OK && intent != null) {
           return processGalleryResult(intent)
        } else {
            null
        }
    }
}

To run the gallery call and get a Bitmap using ImportImageContract, the following code is used:

 val galleryImageLauncher =
            registerForActivityResult(ImportImageContract(this)) { resultEntity ->
                lifecycleScope.launch(Dispatchers.Default) {
                    val activity = this@MainActivity
                    val sdk = ScanbotSDK(activity)
                    if (!sdk.licenseInfo.isValid) {
                        withContext(Dispatchers.Main) {
                            Toast.makeText(
                                activity,
                                "License has expired!",
                                Toast.LENGTH_LONG
                            ).show()
                        }
                    } else {
                        resultEntity?.let { bitmap ->
                           // Image processing is carried out
                           // processImage()
                        }
                    }
                }
            }
        findViewById<View>(R.id.import_image).setOnClickListener {
            galleryImageLauncher.launch(Unit)
        }

Creating the scanner​

Creating the Scanner
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caution

When createBarcodeScanner() is called, a new BarcodeScanner is created and memory is initialized for it. Please avoid creating new scanners for each import action if multiple import operations are expected.

BarcodeScanner offers two detection methods:

  • fun scanFromBitmap(bitmap: Bitmap, frameOrientation: Int): BarcodeScannerResult?
  • fun scanFromJpeg(jpeg: ByteArray, frameOrientation: Int): BarcodeScannerResult?

These methods detect barcodes on an image (JPG file or Bitmap) regardless of the image source (e.g., scanned document image, image picked from photo library, etc.).

Detecting barcodes​

Employ the Scanbot SDK to detect the desired element on the imported bitmap.

Scanning from Bitmap
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Input arguments​

  • bitmap: Bitmap: Bitmap of the source image
  • jpeg: ByteArray: the byte array of the JPG source image
  • frameOrientation: Int: the frame orientation degrees

Handling the results​

Here is a simple example of presenting the result: BarcodeScannerResult data separated by newline characters, displayed in a Toast notification.

Handling the Result
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Full API references for the result class are available here.

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