Implemented decoding EPC QR Code on Android

composeApp/build.gradle.kts

@@ -109,6 +109,12 @@ kotlin {
             implementation(libs.androidx.biometric)
 
             implementation(libs.favre.bcrypt)
+
+            // for reading EPC QR Codes from camera
+            implementation(libs.zxing.core)
+            implementation(libs.camerax.camera2)
+            implementation(libs.camerax.view)
+            implementation(libs.camerax.lifecycle)
         }
 
         iosMain.dependencies {

composeApp/src/androidMain/AndroidManifest.xml

@@ -4,6 +4,9 @@
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.USE_BIOMETRIC" />
 
+    <uses-feature android:name="android.hardware.camera.any" android:required="false" />
+    <uses-permission android:name="android.permission.CAMERA" />
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"

composeApp/src/androidMain/kotlin/net/codinux/banking/ui/service/QrCodeService.android.kt

@@ -0,0 +1,152 @@
+package net.codinux.banking.ui.service
+
+import androidx.camera.core.*
+import androidx.camera.lifecycle.ProcessCameraProvider
+import androidx.camera.view.PreviewView
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalLifecycleOwner
+import androidx.compose.ui.viewinterop.AndroidView
+import androidx.core.content.ContextCompat
+import androidx.fragment.app.FragmentActivity
+import com.google.zxing.*
+import com.google.zxing.common.HybridBinarizer
+import com.google.zxing.qrcode.QRCodeReader
+import net.codinux.banking.persistence.AndroidContext
+import net.codinux.banking.ui.config.DI
+import net.codinux.log.logger
+import java.nio.ByteBuffer
+import java.util.concurrent.Executors
+
+actual object QrCodeService {
+
+    private val cameraExecutor = Executors.newCachedThreadPool()
+
+    private val log by logger()
+
+
+    actual val supportsReadingQrCodesFromCamera = true
+
+    @Composable
+    actual fun readQrCodeFromCamera(resultCallback: (QrCodeReadResult) -> Unit) {
+        val context = AndroidContext.mainActivity
+        val cameraProviderFuture = ProcessCameraProvider.getInstance(context)
+
+        val localContext = LocalContext.current
+        log.info { "LocalContext.current = ${localContext.javaClass} ${localContext}" }
+
+        val lifecycleOwner = LocalLifecycleOwner.current
+//        val context = LocalContext.current
+        val previewView = remember {
+            PreviewView(context)
+        }
+
+        cameraProviderFuture.addListener({
+            // Used to bind the lifecycle of cameras to the lifecycle owner
+            val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
+
+            // Preview
+            val preview = Preview.Builder()
+                .build()
+                .also {
+                    it.setSurfaceProvider(previewView.surfaceProvider)
+                }
+
+            // Select back camera as a default
+            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
+
+            val imageAnalyzer = ImageAnalysis.Builder()
+                .build()
+                .also {
+                    it.setAnalyzer(cameraExecutor, QrCodeImageAnalyzer(resultCallback))
+                }
+
+            try {
+                // Unbind use cases before rebinding
+                cameraProvider.unbindAll()
+
+                // Bind use cases to camera
+                cameraProvider.bindToLifecycle(context as FragmentActivity, cameraSelector, preview, imageAnalyzer)
+
+            } catch(e: Exception) {
+                log.error(e) { "Use case binding failed" }
+            }
+
+        }, ContextCompat.getMainExecutor(context))
+
+
+        AndroidView(factory = { previewView }, modifier = Modifier.fillMaxSize())
+    }
+
+}
+
+
+class QrCodeImageAnalyzer(private val resultCallback: (QrCodeReadResult) -> Unit) : ImageAnalysis.Analyzer {
+
+    private val reader = QRCodeReader()
+
+    private val readerHints = readerHintsForCharset(Charsets.UTF_8.name())
+
+    private val log by logger()
+
+
+    override fun analyze(image: ImageProxy) {
+        try {
+            val bitmap = getBinaryBitmap(image)
+
+            val result = reader.decode(bitmap, readerHints)
+
+            if (result != null && result.text != null) {
+                val decodeResult = DI.epcQrCodeService.decode(result.text)
+                if (decodeResult.charset == null || decodeResult.charset == "UTF-8") {
+                    this.resultCallback(QrCodeReadResult(result.text))
+                } else { // the charset for receiver name, reference, ... was not UTF-8 -> decode image in EPC QR Code's charset
+                    val resultForEncoding = reader.decode(bitmap, readerHintsForCharset(decodeResult.charset))
+
+                    this.resultCallback(QrCodeReadResult(resultForEncoding?.text ?: result.text))
+                }
+            }
+        } catch (e: Throwable) {
+            if (e !is NotFoundException) {
+                log.error(e) { "Could not decode image to QR code" }
+            }
+        }
+
+        image.close() // to continue image analysis / avoid blocking production of further images
+    }
+
+    private fun ByteBuffer.toIntArray(): IntArray {
+        val bytes = this.toByteArray()
+
+        val pixels = IntArray(bytes.size)
+        bytes.indices.forEach { index ->
+            pixels[index] = bytes[index].toInt() and 0xFF
+        }
+
+        return pixels
+    }
+
+    private fun ByteBuffer.toByteArray(): ByteArray {
+        rewind()    // Rewind the buffer to zero
+        val data = ByteArray(remaining())
+        get(data)   // Copy the buffer into a byte array
+        return data // Return the byte array
+    }
+
+    private fun getBinaryBitmap(image: ImageProxy): BinaryBitmap {
+        val buffer = image.planes[0].buffer
+        val bitmapBuffer = buffer.toIntArray()
+
+        val luminanceSource = RGBLuminanceSource(image.width, image.height, bitmapBuffer)
+        return BinaryBitmap(HybridBinarizer(luminanceSource))
+    }
+
+    private fun readerHintsForCharset(charset: String): Map<DecodeHintType, *> = buildMap {
+//        put(DecodeHintType.TRY_HARDER, true) // optimize for accuracy, not speed
+        put(DecodeHintType.CHARACTER_SET, charset)
+    }
+
+}

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/appskeleton/FloatingActionMenu.kt

@@ -23,6 +23,7 @@ import net.codinux.banking.ui.config.Style.FabMenuSpacing
 import net.codinux.banking.ui.config.Style.FabSize
 import net.codinux.banking.ui.config.Style.SmallFabSize
 import net.codinux.banking.ui.model.ShowTransferMoneyDialogData
+import net.codinux.banking.ui.service.QrCodeService
 
 
 private val uiState = DI.uiState
@@ -62,6 +63,14 @@ fun FloatingActionMenu(
                     }
                 }
 
+                if (QrCodeService.supportsReadingQrCodesFromCamera) {
+                    FloatingActionMenuItem("Überweisung aus QR-Code", "Neue Überweisung mit Daten aus EPC QR Code (GiroCode, scan2Code, Zahlen mit Code, ...)", enabled = accountsThatSupportMoneyTransfer.isNotEmpty()) {
+                        handleClick {
+                            uiState.showTransferMoneyFromEpcQrCodeScreen.value = true
+                        }
+                    }
+                }
+
                 FloatingActionMenuItem("Überweisung", "Neue Überweisung", enabled = accountsThatSupportMoneyTransfer.isNotEmpty()) {
                     handleClick {
                         uiState.showTransferMoneyDialogData.value = ShowTransferMoneyDialogData()

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/composables/StateHandler.kt

@@ -15,6 +15,7 @@ private val formatUtil = DI.formatUtil
 fun StateHandler(uiState: UiState, snackbarHostState: SnackbarHostState) {
     val showAddAccountDialog by uiState.showAddAccountDialog.collectAsState()
     val showTransferMoneyDialogData by uiState.showTransferMoneyDialogData.collectAsState()
+    val showTransferMoneyFromEpcQrCodeScreen by uiState.showTransferMoneyFromEpcQrCodeScreen.collectAsState()
     val showCreateEpcQrCodeScreen by uiState.showCreateEpcQrCodeScreen.collectAsState()
 
     val showAccountTransactionDetailsScreenForId by uiState.showAccountTransactionDetailsScreenForId.collectAsState()
@@ -39,6 +40,10 @@ fun StateHandler(uiState: UiState, snackbarHostState: SnackbarHostState) {
         TransferMoneyDialog(data) { uiState.showTransferMoneyDialogData.value = null }
     }
 
+    if (showTransferMoneyFromEpcQrCodeScreen) {
+        TransferMoneyFromQrCodeScreen { uiState.showTransferMoneyFromEpcQrCodeScreen.value = false }
+    }
+
     if (showCreateEpcQrCodeScreen) {
         CreateEpcQrCodeScreen { uiState.showCreateEpcQrCodeScreen.value = false }
     }

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/config/Internationalization.kt

@@ -13,7 +13,9 @@ object Internationalization {
 
     const val ErrorTransferMoney = "Überweisung konnte nicht ausgeführt werden"
 
-    const val SaveToDatabase = "Daten konnten nicht in der Datenbank gespeichert werden"
+    const val ErrorReadEpcQrCode = "Überweisungsdaten konnten nicht aus dem QR Code ausgelesen werden"
+
+    const val ErrorSaveToDatabase = "Daten konnten nicht in der Datenbank gespeichert werden"
 
     const val ErrorBiometricAuthentication = "Biometrische Authentifizierung fehlgeschlagen"
 

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/dialogs/ApplicationErrorDialog.kt

@@ -11,11 +11,10 @@ fun ApplicationErrorDialog(error: ApplicationError, onDismiss: (() -> Unit)? = n
         ErroneousAction.AddAccount -> Internationalization.ErrorAddAccount
         ErroneousAction.UpdateAccountTransactions -> Internationalization.ErrorUpdateAccountTransactions
         ErroneousAction.TransferMoney -> Internationalization.ErrorTransferMoney
-        ErroneousAction.SaveToDatabase -> Internationalization.SaveToDatabase
+        ErroneousAction.ReadEpcQrCode -> Internationalization.ErrorReadEpcQrCode
+        ErroneousAction.SaveToDatabase -> Internationalization.ErrorSaveToDatabase
         ErroneousAction.BiometricAuthentication -> Internationalization.ErrorBiometricAuthentication
     }
 
-    // add exception stacktrace?
-
     ErrorDialog(error.errorMessage, title, error.exception, onDismiss = onDismiss)
 }

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/model/DecodeEpcQrCodeResult.kt

@@ -0,0 +1,7 @@
+package net.codinux.banking.ui.model
+
+data class DecodeEpcQrCodeResult(
+    val data: ShowTransferMoneyDialogData?,
+    val error: String? = null,
+    val charset: String? = null
+)

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/model/error/ErroneousAction.kt

@@ -7,6 +7,8 @@ enum class ErroneousAction {
 
     TransferMoney,
 
+    ReadEpcQrCode,
+
     SaveToDatabase,
 
     BiometricAuthentication

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/screens/TransferMoneyFromQrCodeScreen.kt

@@ -0,0 +1,29 @@
+package net.codinux.banking.ui.screens
+
+import androidx.compose.runtime.Composable
+import net.codinux.banking.ui.config.DI
+import net.codinux.banking.ui.model.error.ErroneousAction
+import net.codinux.banking.ui.service.QrCodeService
+
+@Composable
+fun TransferMoneyFromQrCodeScreen(onClosed: () -> Unit) {
+
+    if (QrCodeService.supportsReadingQrCodesFromCamera) {
+        FullscreenViewBase("Überweisungsdaten aus QR Code lesen", "Abbrechen", onClosed = onClosed) {
+            QrCodeService.readQrCodeFromCamera { result ->
+                onClosed()
+
+                if (result.decodedQrCodeText != null) {
+                    val decodingResult = DI.epcQrCodeService.decode(result.decodedQrCodeText)
+
+                    if (decodingResult.data != null) {
+                        DI.uiState.showTransferMoneyDialogData.value = decodingResult.data
+                    } else if (decodingResult.error != null) {
+                        DI.uiState.applicationErrorOccurred(ErroneousAction.ReadEpcQrCode, decodingResult.error)
+                    }
+                }
+            }
+        }
+    }
+
+}

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/service/EpcQrCodeService.kt

@@ -1,15 +1,36 @@
 package net.codinux.banking.ui.service
 
+import net.codinux.banking.client.model.Amount
 import net.codinux.banking.epcqrcode.EpcQrCode
 import net.codinux.banking.epcqrcode.EpcQrCodeConfig
 import net.codinux.banking.epcqrcode.EpcQrCodeGenerator
+import net.codinux.banking.epcqrcode.parser.EpcQrCodeParser
+import net.codinux.banking.ui.model.DecodeEpcQrCodeResult
+import net.codinux.banking.ui.model.ShowTransferMoneyDialogData
 
 class EpcQrCodeService {
 
-    fun generateEpcQrCode(receiverName: String, iban: String, bic: String?, amount: String?, reference: String?, informationForUser: String? = null, heightAndWidth: Int = EpcQrCode.DefaultHeightAndWidth): ByteArray {
-        val generator = EpcQrCodeGenerator()
+    private val generator = EpcQrCodeGenerator()
 
+    private val parser = EpcQrCodeParser()
+
+
+    fun generateEpcQrCode(receiverName: String, iban: String, bic: String?, amount: String?, reference: String?, informationForUser: String? = null, heightAndWidth: Int = EpcQrCode.DefaultHeightAndWidth): ByteArray {
         return generator.generateEpcQrCode(EpcQrCodeConfig(receiverName, iban, bic, amount, reference, informationForUser, qrCodeHeightAndWidth = heightAndWidth)).bytes
     }
 
+    fun decode(decodedQrCodeText: String): DecodeEpcQrCodeResult {
+        val result = parser.parseEpcQrCode(decodedQrCodeText)
+
+        return if (result.epcQrCode != null) {
+            val code = result.epcQrCode!!
+            DecodeEpcQrCodeResult(
+                ShowTransferMoneyDialogData(null, code.receiverName, code.bic, code.iban, code.amount?.let { Amount(it) }, code.remittance),
+                charset = code.coding.charsetName
+            )
+        } else {
+            DecodeEpcQrCodeResult(null, result.error)
+        }
+    }
+
 }

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/service/QrCodeService.kt

@@ -0,0 +1,16 @@
+package net.codinux.banking.ui.service
+
+import androidx.compose.runtime.Composable
+
+expect object QrCodeService {
+
+    val supportsReadingQrCodesFromCamera: Boolean
+
+    @Composable
+    fun readQrCodeFromCamera(resultCallback: (QrCodeReadResult) -> Unit)
+
+}
+
+data class QrCodeReadResult(
+    val decodedQrCodeText: String?
+)

composeApp/src/commonMain/kotlin/net/codinux/banking/ui/state/UiState.kt

@@ -67,6 +67,8 @@ class UiState : ViewModel() {
 
     val showTransferMoneyDialogData = MutableStateFlow<ShowTransferMoneyDialogData?>(null)
 
+    val showTransferMoneyFromEpcQrCodeScreen = MutableStateFlow(false)
+
     val showCreateEpcQrCodeScreen = MutableStateFlow(false)
 
     val showAccountTransactionDetailsScreenForId = MutableStateFlow<Long?>(null)

composeApp/src/desktopMain/kotlin/net/codinux/banking/ui/service/QrCodeService.desktop.kt

@@ -0,0 +1,14 @@
+package net.codinux.banking.ui.service
+
+import androidx.compose.runtime.Composable
+
+actual object QrCodeService {
+
+    actual val supportsReadingQrCodesFromCamera = false
+
+    @Composable
+    actual fun readQrCodeFromCamera(resultCallback: (QrCodeReadResult) -> Unit) {
+
+    }
+
+}

composeApp/src/iosMain/kotlin/net/codinux/banking/ui/service/QrCodeService.ios.kt

@@ -0,0 +1,14 @@
+package net.codinux.banking.ui.service
+
+import androidx.compose.runtime.Composable
+
+actual object QrCodeService {
+
+    actual val supportsReadingQrCodesFromCamera = false
+
+    @Composable
+    actual fun readQrCodeFromCamera(resultCallback: (QrCodeReadResult) -> Unit) {
+
+    }
+
+}

composeApp/src/jsMain/kotlin/net/codinux/banking/ui/service/QrCodeService.js.kt

@@ -0,0 +1,14 @@
+package net.codinux.banking.ui.service
+
+import androidx.compose.runtime.Composable
+
+actual object QrCodeService {
+
+    actual val supportsReadingQrCodesFromCamera = false
+
+    @Composable
+    actual fun readQrCodeFromCamera(resultCallback: (QrCodeReadResult) -> Unit) {
+
+    }
+
+}

gradle/libs.versions.toml

@@ -32,6 +32,9 @@ androidx-biometric = "1.1.0"
 androidx-test-junit = "1.2.1"
 compose-plugin = "1.6.11"
 
+zxing = "3.5.3"
+camerax = "1.3.4"
+
 junit = "4.13.2"
 
 [libraries]
@@ -69,6 +72,11 @@ androidx-lifecycle-runtime-compose = { group = "org.jetbrains.androidx.lifecycle
 androidx-biometric = { group = "androidx.biometric", name = "biometric", version.ref = "androidx-biometric" }
 kotlinx-coroutines-swing = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-swing", version.ref = "kotlinx-coroutines" }
 
+zxing-core = { group = "com.google.zxing", name = "core", version.ref = "zxing" }
+camerax-camera2 = { group = "androidx.camera", name = "camera-camera2", version.ref = "camerax" }
+camerax-view = { group = "androidx.camera", name = "camera-view", version.ref = "camerax" }
+camerax-lifecycle = { group = "androidx.camera", name = "camera-lifecycle", version.ref = "camerax" }
+
 kotlin-test = { module = "org.jetbrains.kotlin:kotlin-test", version.ref = "kotlin" }
 kotlin-test-junit = { module = "org.jetbrains.kotlin:kotlin-test-junit", version.ref = "kotlin" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }