fixed scaner QR Android

client/android/res/drawable/ic_pairing_back.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FFE8E8EC"
+        android:pathData="M20,11H7.83l5.59,-5.59L12,4l-8,8 8,8 1.41,-1.41L7.83,13H20v-2z" />
+</vector>

client/android/res/drawable/torch_fab_bg.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="oval">
+    <solid android:color="#38FFFFFF" />
+</shape>

client/android/res/layout/camera_preview.xml

@@ -8,4 +8,75 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent" />
 
+    <org.amnezia.vpn.PairingQrScanOverlayView
+        android:id="@+id/pairingScanOverlay"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:visibility="gone" />
+
+    <LinearLayout
+        android:id="@+id/pairingChrome"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="top"
+        android:background="@android:color/transparent"
+        android:orientation="horizontal"
+        android:paddingStart="8dp"
+        android:paddingTop="28dp"
+        android:paddingEnd="16dp"
+        android:paddingBottom="12dp"
+        android:visibility="gone">
+
+        <ImageButton
+            android:id="@+id/pairingBack"
+            android:layout_width="48dp"
+            android:layout_height="48dp"
+            android:layout_gravity="top"
+            android:background="?android:attr/selectableItemBackgroundBorderless"
+            android:contentDescription="@string/pairing_qr_camera_back"
+            android:padding="12dp"
+            android:scaleType="fitCenter"
+            android:src="@drawable/ic_pairing_back" />
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="4dp"
+            android:layout_weight="1"
+            android:orientation="vertical">
+
+            <TextView
+                android:id="@+id/pairingTitle"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/pairing_qr_camera_title"
+                android:textColor="#FFE8E8EC"
+                android:textSize="20sp"
+                android:textStyle="bold" />
+
+            <TextView
+                android:id="@+id/pairingSubtitle"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:text="@string/pairing_qr_camera_subtitle"
+                android:textColor="#FFB8B8C0"
+                android:textSize="14sp" />
+        </LinearLayout>
+    </LinearLayout>
+
+    <TextView
+        android:id="@+id/torchButton"
+        android:layout_width="56dp"
+        android:layout_height="56dp"
+        android:layout_gravity="bottom|center_horizontal"
+        android:layout_marginBottom="32dp"
+        android:background="@drawable/torch_fab_bg"
+        android:clickable="true"
+        android:focusable="true"
+        android:gravity="center"
+        android:text="🔦"
+        android:textSize="26sp"
+        android:contentDescription="@string/camera_torch" />
+
 </FrameLayout>

client/android/res/values-ru/strings.xml

@@ -24,5 +24,10 @@
     <string name="notificationSettingsDialogMessage">Для показа уведомлений необходимо включить уведомления в системных настройках</string>
     <string name="openNotificationSettings">Открыть настройки уведомлений</string>
 
+    <string name="camera_torch">Фонарик</string>
+    <string name="pairing_qr_camera_title">Добавить устройство по QR</string>
+    <string name="pairing_qr_camera_subtitle">Отсканируйте QR сессии на устройстве, которое хотите добавить. Перед отправкой подписки будет подтверждение.</string>
+    <string name="pairing_qr_camera_back">Назад</string>
+
     <string name="tvNoFileBrowser">Пожалуйста, установите приложение для просмотра файлов</string>
 </resources>

client/android/res/values/strings.xml

@@ -27,6 +27,10 @@
     <string name="cameraPermissionDialogTitle">Camera access</string>
     <string name="cameraPermissionDialogMessage">To scan a QR code for device pairing, Amnezia VPN needs access to the camera.</string>
     <string name="cameraPermissionContinue">Continue</string>
+    <string name="camera_torch">Flashlight</string>
+    <string name="pairing_qr_camera_title">Add device via QR</string>
+    <string name="pairing_qr_camera_subtitle">Scan the session QR shown on the device you want to add. You will confirm before the subscription is sent.</string>
+    <string name="pairing_qr_camera_back">Back</string>
 
     <string name="tvNoFileBrowser">Please install a file management utility to browse files</string>
 </resources>

client/android/src/org/amnezia/vpn/AmneziaActivity.kt

@@ -42,6 +42,9 @@ import androidx.core.view.OnApplyWindowInsetsListener
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.WindowInsetsControllerCompat
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.LifecycleRegistry
 import java.io.IOException
 import kotlin.LazyThreadSafetyMode.NONE
 import kotlin.coroutines.CoroutineContext
@@ -79,7 +82,12 @@ private const val PREFS_NOTIFICATION_PERMISSION_ASKED = "NOTIFICATION_PERMISSION
 private const val OPEN_FILE_AFTER_RESUME_DELAY_MS = 400L
 private const val KEY_PENDING_OPEN_FILE_URI = "pending_open_file_uri"
 
-class AmneziaActivity : QtActivity() {
+class AmneziaActivity : QtActivity(), LifecycleOwner {
+
+    private val lifecycleRegistry = LifecycleRegistry(this)
+
+    override val lifecycle: Lifecycle
+        get() = lifecycleRegistry
 
     private lateinit var mainScope: CoroutineScope
     private val qtInitialized = CompletableDeferred<Unit>()
@@ -101,6 +109,7 @@ class AmneziaActivity : QtActivity() {
     private var openFileDeliveryScheduled = false
 
     private var pairingQrEmbeddedCamera: PairingQrEmbeddedCamera? = null
+    private var lastPairingQrReaderStartUptimeMs: Long = 0L
 
     private val vpnServiceEventHandler: Handler by lazy(NONE) {
         object : Handler(Looper.getMainLooper()) {
@@ -208,6 +217,7 @@ class AmneziaActivity : QtActivity() {
         registerBroadcastReceivers()
         intent?.let(::processIntent)
         runBlocking { vpnProto = proto.await() }
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE)
     }
 
     override fun onSaveInstanceState(outState: Bundle) {
@@ -265,6 +275,7 @@ class AmneziaActivity : QtActivity() {
 
     override fun onStart() {
         super.onStart()
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_START)
         Log.d(TAG, "Start Amnezia activity")
         mainScope.launch {
             qtInitialized.await()
@@ -288,6 +299,7 @@ class AmneziaActivity : QtActivity() {
             qtInitialized.await()
             QtAndroidController.onServiceDisconnected()
         }
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_STOP)
         super.onStop()
     }
 
@@ -360,6 +372,7 @@ class AmneziaActivity : QtActivity() {
         if (qtInitialized.isCompleted) {
             QtAndroidController.onActivityPaused()
         }
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_PAUSE)
         super.onPause()
         isActivityResumed = false
         // Cancel all pending operations when activity pauses
@@ -370,6 +383,7 @@ class AmneziaActivity : QtActivity() {
 
     override fun onResume() {
         super.onResume()
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_RESUME)
         isActivityResumed = true
         Log.d(TAG, "Resume Amnezia activity")
         if (qtInitialized.isCompleted) {
@@ -486,6 +500,7 @@ class AmneziaActivity : QtActivity() {
         unregisterBroadcastReceiver(notificationStateReceiver)
         notificationStateReceiver = null
         mainScope.cancel()
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_DESTROY)
         super.onDestroy()
     }
 
@@ -1011,6 +1026,21 @@ class AmneziaActivity : QtActivity() {
         }
     }
 
+    @Suppress("unused")
+    fun startPairingQrCodeReader() {
+        val now = SystemClock.uptimeMillis()
+        if (now - lastPairingQrReaderStartUptimeMs < 1200L) {
+            Log.w(TAG, "startPairingQrCodeReader: suppressed duplicate (${now - lastPairingQrReaderStartUptimeMs}ms)")
+            return
+        }
+        lastPairingQrReaderStartUptimeMs = now
+        Log.v(TAG, "Start pairing QR camera")
+        Intent(this, CameraActivity::class.java).also {
+            it.putExtra(CameraActivity.EXTRA_PAIRING_QR_CAMERA, true)
+            startActivity(it)
+        }
+    }
+
     @Suppress("unused")
     fun setSaveLogs(enabled: Boolean) {
         Log.v(TAG, "Set save logs: $enabled")

client/android/src/org/amnezia/vpn/CameraActivity.kt

@@ -2,47 +2,401 @@ package org.amnezia.vpn
 
 import android.Manifest
 import android.annotation.SuppressLint
+import android.content.Intent
 import android.content.pm.PackageManager
+import android.graphics.Color
+import android.graphics.drawable.GradientDrawable
 import android.os.Bundle
 import android.view.MotionEvent.ACTION_DOWN
 import android.view.MotionEvent.ACTION_UP
+import android.graphics.RectF
+import android.view.Gravity
+import android.view.View
+import android.widget.FrameLayout
 import android.widget.Toast
 import androidx.activity.ComponentActivity
+import androidx.activity.OnBackPressedCallback
 import androidx.activity.result.contract.ActivityResultContracts.RequestPermission
+import androidx.camera.core.Camera
 import androidx.camera.core.CameraSelector
 import androidx.camera.core.ExperimentalGetImage
 import androidx.camera.core.FocusMeteringAction
 import androidx.camera.core.FocusMeteringAction.FLAG_AE
 import androidx.camera.core.FocusMeteringAction.FLAG_AF
 import androidx.camera.core.ImageAnalysis
+import androidx.camera.core.ImageProxy
 import androidx.camera.core.Preview
 import androidx.camera.lifecycle.ProcessCameraProvider
+import androidx.camera.view.PreviewView
+import androidx.camera.view.TransformExperimental
+import androidx.camera.view.transform.CoordinateTransform
+import androidx.camera.view.transform.ImageProxyTransformFactory
+import androidx.camera.view.transform.OutputTransform
 import androidx.core.content.ContextCompat
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowCompat
+import androidx.core.view.WindowInsetsCompat
+import androidx.lifecycle.Observer
+import com.google.mlkit.vision.barcode.BarcodeScanner
 import com.google.mlkit.vision.barcode.BarcodeScannerOptions.Builder
 import com.google.mlkit.vision.barcode.BarcodeScanning
-import com.google.mlkit.vision.barcode.ZoomSuggestionOptions
 import com.google.mlkit.vision.barcode.common.Barcode
 import com.google.mlkit.vision.common.InputImage
 import org.amnezia.vpn.databinding.CameraPreviewBinding
 import org.amnezia.vpn.qt.QtAndroidController
 import org.amnezia.vpn.util.Log
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicReference
+import kotlin.math.roundToInt
 
 private const val TAG = "CameraActivity"
 
+@OptIn(TransformExperimental::class)
 class CameraActivity : ComponentActivity() {
 
+    companion object {
+        const val EXTRA_PAIRING_QR_CAMERA = "org.amnezia.vpn.extra.PAIRING_QR_CAMERA"
+    }
+
     private lateinit var viewBinding: CameraPreviewBinding
-    private lateinit var cameraProvider: ProcessCameraProvider
+    private var cameraProvider: ProcessCameraProvider? = null
+    private var boundCamera: Camera? = null
+    private var boundImageAnalysis: ImageAnalysis? = null
+    private var torchOn: Boolean = false
+
+    /** CameraX analyzer thread only; ML Kit Task callbacks use [ContextCompat.getMainExecutor] so they are not rejected after [ExecutorService.shutdown]. */
+    private var imageAnalysisExecutor: ExecutorService? = null
+
+    /** After a successful decode, ignore further frames (ML Kit otherwise hits "detector is already closed"). */
+    private val qrHandledOrClosing = AtomicBoolean(false)
+
+    /**
+     * Pairing mode: QR was accepted by Qt ([decodeQrCode] true) and we are finishing normally.
+     * Do not apply JNI reopen cooldown on destroy — user may cancel confirm and return to scan immediately.
+     */
+    private var pairingQrDeliveredToQt = false
+
+    /**
+     * Pairing mode: user closed camera via back / toolbar (not a successful scan).
+     * Skip JNI reopen cooldown — otherwise Qt stays on the black overlay shell until cooldown ends and a second back pops the page.
+     */
+    private var pairingQrUserDismissedCamera = false
+
+    private var barcodeScanner: BarcodeScanner? = null
+
+    /**
+     * [PreviewView.getOutputTransform] is main-thread-only; the image analyzer runs on a background
+     * executor. Refresh this cache whenever layout / preview geometry may change.
+     */
+    private val cachedPreviewOutputTransform = AtomicReference<OutputTransform?>(null)
+
+    private var previewTransformLayoutListener: View.OnLayoutChangeListener? = null
+
+    private var previewStreamStateObserver: Observer<PreviewView.StreamState>? = null
+
+    @Volatile
+    private var pairingGeomHeaderBottomPx = 0f
+
+    @Volatile
+    private var pairingGeomStatusBarTopPx = 0f
+
+    @Volatile
+    private var pairingGeomDensity = 1f
 
     @ExperimentalGetImage
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         viewBinding = CameraPreviewBinding.inflate(layoutInflater)
         setContentView(viewBinding.root)
+        viewBinding.viewFinder.scaleType = PreviewView.ScaleType.FILL_CENTER
+
+        if (intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+            WindowCompat.setDecorFitsSystemWindows(window, false)
+            val density = resources.displayMetrics.density
+            val padH = (8 * density).toInt()
+            val padTopBase = (28 * density).toInt()
+            val padBottom = (12 * density).toInt()
+            ViewCompat.setOnApplyWindowInsetsListener(viewBinding.pairingChrome) { v, windowInsets ->
+                val bars = windowInsets.getInsets(WindowInsetsCompat.Type.statusBars())
+                v.setPadding(padH, padTopBase + bars.top, (16 * density).toInt(), padBottom)
+                v.post { onPairingLayoutGeometryChanged() }
+                windowInsets
+            }
+            viewBinding.pairingScanOverlay.visibility = View.VISIBLE
+            viewBinding.pairingChrome.visibility = View.VISIBLE
+            viewBinding.root.addOnLayoutChangeListener { _, _, _, _, _, _, _, _, _ ->
+                onPairingLayoutGeometryChanged()
+            }
+            viewBinding.root.post {
+                onPairingLayoutGeometryChanged()
+                applyPairingTorchButtonChrome()
+            }
+        }
+
+        viewBinding.pairingBack.setOnClickListener { releaseCameraAndFinish() }
+
+        onBackPressedDispatcher.addCallback(
+            this,
+            object : OnBackPressedCallback(true) {
+                override fun handleOnBackPressed() {
+                    releaseCameraAndFinish()
+                }
+            }
+        )
+
+        viewBinding.torchButton.setOnClickListener {
+            torchOn = !torchOn
+            try {
+                boundCamera?.cameraControl?.enableTorch(torchOn)
+            } catch (e: Exception) {
+                Log.e(TAG, "Torch: $e")
+            }
+            if (intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+                applyPairingTorchButtonChrome()
+            }
+        }
 
         checkPermissions(onSuccess = ::startCamera, onFail = ::finish)
     }
 
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        setIntent(intent)
+        if (!intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+            return
+        }
+        if (!::viewBinding.isInitialized) {
+            return
+        }
+        Log.v(TAG, "onNewIntent: rebind pairing camera")
+        cleanupCameraResources()
+        qrHandledOrClosing.set(false)
+        pairingQrDeliveredToQt = false
+        pairingQrUserDismissedCamera = false
+        torchOn = false
+        viewBinding.pairingScanOverlay.visibility = View.VISIBLE
+        viewBinding.pairingChrome.visibility = View.VISIBLE
+        viewBinding.root.post {
+            onPairingLayoutGeometryChanged()
+            applyPairingTorchButtonChrome()
+        }
+        checkPermissions(onSuccess = ::startCamera, onFail = ::finish)
+    }
+
+    override fun onDestroy() {
+        cleanupCameraResources()
+        val pairing = intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)
+        if (pairing && !pairingQrDeliveredToQt && !pairingQrUserDismissedCamera) {
+            try {
+                QtAndroidController.onPairingQrCameraClosed()
+            } catch (t: Throwable) {
+                Log.e(TAG, "onPairingQrCameraClosed: $t")
+            }
+        }
+        super.onDestroy()
+    }
+
+    /** Idempotent: safe from back, successful decode, or process death. */
+    private fun cleanupCameraResources() {
+        qrHandledOrClosing.set(true)
+        try {
+            boundImageAnalysis?.clearAnalyzer()
+        } catch (_: Exception) {
+        }
+        boundImageAnalysis = null
+        try {
+            barcodeScanner?.close()
+        } catch (_: Exception) {
+        }
+        barcodeScanner = null
+        try {
+            boundCamera?.cameraControl?.enableTorch(false)
+        } catch (_: Exception) {
+        }
+        boundCamera = null
+        try {
+            cameraProvider?.unbindAll()
+        } catch (_: Exception) {
+        }
+        imageAnalysisExecutor?.let { ex ->
+            try {
+                ex.shutdown()
+            } catch (_: Exception) {
+            }
+        }
+        imageAnalysisExecutor = null
+        previewTransformLayoutListener?.let { listener ->
+            if (::viewBinding.isInitialized) {
+                viewBinding.viewFinder.removeOnLayoutChangeListener(listener)
+            }
+        }
+        previewTransformLayoutListener = null
+        previewStreamStateObserver?.let { obs ->
+            if (::viewBinding.isInitialized) {
+                viewBinding.viewFinder.previewStreamState.removeObserver(obs)
+            }
+        }
+        previewStreamStateObserver = null
+        cachedPreviewOutputTransform.set(null)
+    }
+
+    /** Must run on the main thread (uses [PreviewView.getOutputTransform]). */
+    private fun refreshCachedPreviewOutputTransform() {
+        if (!::viewBinding.isInitialized) {
+            return
+        }
+        val vf = viewBinding.viewFinder
+        try {
+            val out = vf.outputTransform
+            cachedPreviewOutputTransform.set(out)
+        } catch (t: Throwable) {
+            Log.e(TAG, "refreshCachedPreviewOutputTransform: $t")
+            cachedPreviewOutputTransform.set(null)
+        }
+    }
+
+    /**
+     * Schedules [refreshCachedPreviewOutputTransform] on the main thread (safe from any thread).
+     */
+    private fun scheduleCachedPreviewOutputTransformRefresh() {
+        if (!::viewBinding.isInitialized) {
+            return
+        }
+        viewBinding.viewFinder.post { refreshCachedPreviewOutputTransform() }
+    }
+
+    /**
+     * iOS `layoutScanOverlayGeometry`: hole + torch vertical position; keeps ML Kit ROI aligned with overlay.
+     */
+    private fun onPairingLayoutGeometryChanged() {
+        if (!::viewBinding.isInitialized || !intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+            return
+        }
+        val root = viewBinding.root
+        val chrome = viewBinding.pairingChrome
+        val w = root.width
+        val h = root.height
+        if (w <= 0 || h <= 0) {
+            return
+        }
+        val density = resources.displayMetrics.density
+        val headerBottom = if (chrome.visibility == View.VISIBLE) chrome.bottom.toFloat() else 0f
+        val insets = ViewCompat.getRootWindowInsets(root)
+        val statusTop = insets?.getInsets(WindowInsetsCompat.Type.statusBars())?.top?.toFloat() ?: 0f
+        val safeBottom = insets?.getInsets(WindowInsetsCompat.Type.systemBars())?.bottom?.toFloat() ?: 0f
+
+        pairingGeomHeaderBottomPx = headerBottom
+        pairingGeomStatusBarTopPx = statusTop
+        pairingGeomDensity = density
+
+        viewBinding.pairingScanOverlay.setPairingHeaderBottomPx(headerBottom)
+
+        val hole = PairingQrScanGeometry.pairingIosStyleHoleRectF(w, h, headerBottom, statusTop, density)
+        val torchCy = PairingQrScanGeometry.pairingIosStyleTorchCenterYPx(
+            hole.bottom,
+            h.toFloat(),
+            headerBottom,
+            safeBottom,
+            density
+        )
+        val torchSizePx = (56f * density).roundToInt().coerceAtLeast(1)
+        val lp = viewBinding.torchButton.layoutParams as FrameLayout.LayoutParams
+        lp.gravity = Gravity.TOP or Gravity.CENTER_HORIZONTAL
+        lp.topMargin = (torchCy - torchSizePx / 2f).roundToInt().coerceAtLeast(0)
+        lp.bottomMargin = 0
+        viewBinding.torchButton.layoutParams = lp
+    }
+
+    /** Matches iOS pairing overlay torch on/off chrome (background + golden border). */
+    private fun applyPairingTorchButtonChrome() {
+        if (!::viewBinding.isInitialized || !intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+            return
+        }
+        val btn = viewBinding.torchButton
+        val d = resources.displayMetrics.density
+        val alpha = if (torchOn) (0.42f * 255f).toInt() else (0.22f * 255f).toInt()
+        val bg = GradientDrawable().apply {
+            shape = GradientDrawable.OVAL
+            setColor(Color.argb(alpha, 255, 255, 255))
+            if (torchOn) {
+                setStroke((2f * d).roundToInt(), Color.rgb(255, 191, 115))
+            } else {
+                setStroke(0, 0)
+            }
+        }
+        btn.background = bg
+    }
+
+    /**
+     * Maps the pairing scan square from [PreviewView] pixel space into the same coordinate system
+     * as ML Kit barcodes for this [imageProxy] (rotation-aware). Falls back to FILL_CENTER math
+     * if the transform is not ready — never returns view-space rects as image-space.
+     */
+    private fun pairingHoleRectInImageSpace(
+        viewFinder: PreviewView,
+        imageProxy: ImageProxy,
+        imageWidth: Int,
+        imageHeight: Int
+    ): RectF {
+        val vw = viewFinder.width
+        val vh = viewFinder.height
+        fun geomFallback(): RectF =
+            PairingQrScanGeometry.pairingIosStyleHoleInImageCoords(
+                vw,
+                vh,
+                pairingGeomHeaderBottomPx,
+                pairingGeomStatusBarTopPx,
+                pairingGeomDensity,
+                imageWidth,
+                imageHeight
+            )
+        if (vw <= 0 || vh <= 0 || imageWidth <= 0 || imageHeight <= 0) {
+            return geomFallback()
+        }
+        return try {
+            val previewOut = cachedPreviewOutputTransform.get()
+            if (previewOut == null) {
+                geomFallback()
+            } else {
+                val imageFactory = ImageProxyTransformFactory().apply {
+                    setUsingRotationDegrees(true)
+                }
+                val imageOut = imageFactory.getOutputTransform(imageProxy)
+                val holeView = PairingQrScanGeometry.pairingIosStyleHoleRectF(
+                    vw,
+                    vh,
+                    pairingGeomHeaderBottomPx,
+                    pairingGeomStatusBarTopPx,
+                    pairingGeomDensity
+                )
+                if (holeView.width() <= 0f || holeView.height() <= 0f) {
+                    return geomFallback()
+                }
+                val hole = RectF(holeView)
+                CoordinateTransform(previewOut, imageOut).mapRect(hole)
+                hole
+            }
+        } catch (t: Throwable) {
+            Log.e(TAG, "pairingHoleRectInImageSpace: $t")
+            geomFallback()
+        }
+    }
+
+    private fun releaseCameraAndFinish() {
+        if (intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+            pairingQrUserDismissedCamera = true
+            try {
+                QtAndroidController.onPairingQrCameraUserDismissed()
+            } catch (t: Throwable) {
+                Log.e(TAG, "onPairingQrCameraUserDismissed: $t")
+            }
+        }
+        cleanupCameraResources()
+        finish()
+    }
+
     private fun checkPermissions(onSuccess: () -> Unit, onFail: () -> Unit) {
         if (checkSelfPermission(Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
             onSuccess()
@@ -67,26 +421,41 @@ class CameraActivity : ComponentActivity() {
 
         cameraProviderFuture.addListener({
             cameraProvider = cameraProviderFuture.get()
-            bindPreview()
-            bindImageAnalysis()
+            bindCameraUseCases()
         }, ContextCompat.getMainExecutor(this))
     }
 
     @SuppressLint("ClickableViewAccessibility")
-    private fun bindPreview() {
+    @ExperimentalGetImage
+    private fun bindCameraUseCases() {
+        val provider = cameraProvider ?: return
+        imageAnalysisExecutor?.shutdown()
+        imageAnalysisExecutor = Executors.newSingleThreadExecutor()
+
         val viewFinder = viewBinding.viewFinder
         val preview = Preview.Builder().build().also {
             it.setSurfaceProvider(viewFinder.surfaceProvider)
         }
 
-        val camera = cameraProvider.bindToLifecycle(this, CameraSelector.DEFAULT_BACK_CAMERA, preview)
+        val imageAnalysis = ImageAnalysis.Builder()
+            .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
+            .build()
+
+        val camera = provider.bindToLifecycle(
+            this,
+            CameraSelector.DEFAULT_BACK_CAMERA,
+            preview,
+            imageAnalysis
+        )
+        boundCamera = camera
+        boundImageAnalysis = imageAnalysis
 
         viewFinder.setOnTouchListener { _, motionEvent ->
             when (motionEvent.action) {
                 ACTION_DOWN -> true
                 ACTION_UP -> {
                     val point = viewFinder
-                        .meteringPointFactory.createPoint(motionEvent.x, motionEvent.x)
+                        .meteringPointFactory.createPoint(motionEvent.x, motionEvent.y)
 
                     val action = FocusMeteringAction
                         .Builder(point, FLAG_AF or FLAG_AE).build()
@@ -98,58 +467,117 @@ class CameraActivity : ComponentActivity() {
                 else -> false
             }
         }
-    }
 
-    @ExperimentalGetImage
-    private fun bindImageAnalysis() {
-        val imageAnalysis = ImageAnalysis.Builder().build()
+        if (intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)) {
+            previewTransformLayoutListener?.let { viewFinder.removeOnLayoutChangeListener(it) }
+            val layoutListener = View.OnLayoutChangeListener { _, _, _, _, _, _, _, _, _ ->
+                scheduleCachedPreviewOutputTransformRefresh()
+                onPairingLayoutGeometryChanged()
+            }
+            previewTransformLayoutListener = layoutListener
+            viewFinder.addOnLayoutChangeListener(layoutListener)
+            previewStreamStateObserver?.let { viewFinder.previewStreamState.removeObserver(it) }
+            val streamObserver = Observer<PreviewView.StreamState> { state ->
+                if (state == PreviewView.StreamState.STREAMING) {
+                    scheduleCachedPreviewOutputTransformRefresh()
+                    viewFinder.post { onPairingLayoutGeometryChanged() }
+                }
+            }
+            previewStreamStateObserver = streamObserver
+            viewFinder.previewStreamState.observe(this, streamObserver)
+            scheduleCachedPreviewOutputTransformRefresh()
+        }
 
-        val camera = cameraProvider.bindToLifecycle(this, CameraSelector.DEFAULT_BACK_CAMERA, imageAnalysis)
-
-        val barcodeScanner = BarcodeScanning.getClient(
+        try {
+            barcodeScanner?.close()
+        } catch (_: Exception) {
+        }
+        // No ZoomSuggestionOptions: ML Kit "scanner-auto-zoom" is off-spec for pairing and skews crop vs our ROI.
+        barcodeScanner = BarcodeScanning.getClient(
             Builder()
                 .setBarcodeFormats(Barcode.FORMAT_QR_CODE)
-                .setZoomSuggestionOptions(
-                    ZoomSuggestionOptions.Builder { zoomLevel ->
-                        camera.cameraControl.setZoomRatio(zoomLevel)
-                        true
-                    }.apply {
-                        camera.cameraInfo.zoomState.value?.maxZoomRatio?.let { maxZoomRation ->
-                            setMaxSupportedZoomRatio(maxZoomRation)
-                        }
-                    }.build()
-                ).build()
+                .build()
         )
 
-        // optimization
         val checkedBarcodes = hashSetOf<String>()
+        val analysisExecutor = imageAnalysisExecutor!!
+        val mainExecutor = ContextCompat.getMainExecutor(this)
+        val pairingQrMode = intent.getBooleanExtra(EXTRA_PAIRING_QR_CAMERA, false)
 
-        imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(this)) { imageProxy ->
-            imageProxy.image?.let { InputImage.fromMediaImage(it, imageProxy.imageInfo.rotationDegrees) }
-                ?.let { image ->
-                    barcodeScanner.process(image).addOnSuccessListener { barcodes ->
-                        barcodes.firstOrNull()?.let { barcode ->
-                            barcode.displayValue?.let { code ->
-                                if (code.isNotEmpty() && code !in checkedBarcodes) {
-                                    if (QtAndroidController.decodeQrCode(code)) {
-                                        barcodeScanner.close()
+        imageAnalysis.setAnalyzer(analysisExecutor) { imageProxy ->
+            if (qrHandledOrClosing.get()) {
+                imageProxy.close()
+                return@setAnalyzer
+            }
+            val mediaImage = imageProxy.image
+            if (mediaImage == null) {
+                imageProxy.close()
+                return@setAnalyzer
+            }
+            val image = InputImage.fromMediaImage(mediaImage, imageProxy.imageInfo.rotationDegrees)
+            val viewW = viewFinder.width
+            val viewH = viewFinder.height
+            val pairingRoi = if (pairingQrMode) {
+                pairingHoleRectInImageSpace(viewFinder, imageProxy, image.width, image.height)
+            } else {
+                null
+            }
+            val scanner = barcodeScanner ?: run {
+                imageProxy.close()
+                return@setAnalyzer
+            }
+            scanner.process(image)
+                .addOnSuccessListener(mainExecutor) { barcodes ->
+                    if (qrHandledOrClosing.get()) {
+                        return@addOnSuccessListener
+                    }
+                    val barcode = if (pairingQrMode) {
+                        val roi = pairingRoi
+                            ?: PairingQrScanGeometry.pairingIosStyleHoleInImageCoords(
+                                viewW,
+                                viewH,
+                                pairingGeomHeaderBottomPx,
+                                pairingGeomStatusBarTopPx,
+                                pairingGeomDensity,
+                                image.width,
+                                image.height
+                            )
+                        barcodes.firstOrNull {
+                            PairingQrScanGeometry.barcodeMatchesPairingHole(
+                                roi,
+                                image.width,
+                                image.height,
+                                it
+                            )
+                        }
+                    } else {
+                        barcodes.firstOrNull()
+                    }
+                    barcode?.displayValue?.let { code ->
+                            if (code.isNotEmpty() && code !in checkedBarcodes) {
+                                checkedBarcodes.add(code)
+                                if (QtAndroidController.decodeQrCode(code)) {
+                                    if (qrHandledOrClosing.compareAndSet(false, true)) {
+                                        if (pairingQrMode) {
+                                            pairingQrDeliveredToQt = true
+                                        }
                                         stopCamera()
                                     }
-                                    checkedBarcodes.add(code)
                                 }
                             }
-                        }
-                    }.addOnFailureListener {
-                        Log.e(TAG, "Processing QR code image failed: ${it.message}")
-                    }.addOnCompleteListener {
-                        imageProxy.close()
                     }
                 }
+                .addOnFailureListener(mainExecutor) {
+                    Log.e(TAG, "Processing QR code image failed: ${it.message}")
+                }
+                .addOnCompleteListener(mainExecutor) {
+                    imageProxy.close()
+                }
         }
     }
 
     private fun stopCamera() {
-        cameraProvider.unbindAll()
+        cleanupCameraResources()
         finish()
     }
 }

client/android/src/org/amnezia/vpn/PairingQrEmbeddedCamera.kt

@@ -1,7 +1,9 @@
 package org.amnezia.vpn
 
 import android.graphics.Color
+import android.graphics.PixelFormat
 import android.graphics.drawable.ColorDrawable
+import android.view.View
 import android.view.ViewGroup
 import android.widget.FrameLayout
 import androidx.camera.core.Camera
@@ -19,6 +21,8 @@ import com.google.mlkit.vision.barcode.common.Barcode
 import com.google.mlkit.vision.common.InputImage
 import org.amnezia.vpn.qt.QtAndroidController
 import org.amnezia.vpn.util.Log
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
 
 private const val TAG = "PairingQrEmbedded"
 
@@ -33,6 +37,10 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
 
     private val windowBgOpaque = ColorDrawable(Color.parseColor("#0E0E11"))
 
+    private var savedWindowFormat: Int? = null
+
+    private var imageAnalysisExecutor: ExecutorService? = null
+
     fun start() {
         activity.runOnUiThread {
             if (previewView != null) {
@@ -40,15 +48,26 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
             }
             checkedBarcodes.clear()
             activity.window.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
+            val lp = activity.window.attributes
+            if (savedWindowFormat == null) {
+                savedWindowFormat = lp.format
+            }
+            lp.format = PixelFormat.TRANSLUCENT
+            activity.window.attributes = lp
 
             val content = activity.findViewById<ViewGroup>(android.R.id.content)
+            content.clipChildren = false
+            content.clipToPadding = false
             val pv = PreviewView(activity).apply {
                 layoutParams = FrameLayout.LayoutParams(
                     ViewGroup.LayoutParams.MATCH_PARENT,
                     ViewGroup.LayoutParams.MATCH_PARENT
                 )
+                // TextureView-style path so preview can show through “holes” in Qt Quick on some OEMs (e.g. Samsung).
                 implementationMode = PreviewView.ImplementationMode.COMPATIBLE
                 scaleType = PreviewView.ScaleType.FILL_CENTER
+                setBackgroundColor(Color.TRANSPARENT)
+                importantForAccessibility = View.IMPORTANT_FOR_ACCESSIBILITY_NO
             }
             content.addView(pv, 0)
             for (i in 1 until content.childCount) {
@@ -61,6 +80,10 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
                 try {
                     cameraProvider = cameraProviderFuture.get()
                     bindUseCases(pv)
+                    pv.post {
+                        pv.requestLayout()
+                        pv.invalidate()
+                    }
                 } catch (e: Exception) {
                     Log.e(TAG, "Camera bind failed: $e")
                     stop()
@@ -72,6 +95,8 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
     private fun bindUseCases(viewFinder: PreviewView) {
         val provider = cameraProvider ?: return
         provider.unbindAll()
+        imageAnalysisExecutor?.shutdown()
+        imageAnalysisExecutor = Executors.newSingleThreadExecutor()
 
         val preview = Preview.Builder().build().also {
             it.setSurfaceProvider(viewFinder.surfaceProvider)
@@ -94,7 +119,13 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
                 .setBarcodeFormats(Barcode.FORMAT_QR_CODE)
                 .setZoomSuggestionOptions(
                     ZoomSuggestionOptions.Builder { zoomLevel ->
-                        cam.cameraControl.setZoomRatio(zoomLevel)
+                        activity.runOnUiThread {
+                            try {
+                                cam.cameraControl.setZoomRatio(zoomLevel)
+                            } catch (e: Exception) {
+                                Log.e(TAG, "Zoom: $e")
+                            }
+                        }
                         true
                     }.apply {
                         cam.cameraInfo.zoomState.value?.maxZoomRatio?.let { maxZoom ->
@@ -105,28 +136,32 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
         )
 
         val scanner = barcodeScanner!!
-        imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(activity)) { imageProxy ->
+        val analysisExecutor = imageAnalysisExecutor!!
+        imageAnalysis.setAnalyzer(analysisExecutor) { imageProxy ->
             val mediaImage = imageProxy.image ?: run {
                 imageProxy.close()
                 return@setAnalyzer
             }
             val image = InputImage.fromMediaImage(mediaImage, imageProxy.imageInfo.rotationDegrees)
-            scanner.process(image).addOnSuccessListener { barcodes ->
-                barcodes.firstOrNull()?.displayValue?.let { code ->
-                    if (code.isNotEmpty() && code !in checkedBarcodes) {
-                        checkedBarcodes.add(code)
-                        if (QtAndroidController.decodeQrCode(code)) {
-                            scanner.close()
-                            barcodeScanner = null
-                            stop()
+            scanner.process(image)
+                .addOnSuccessListener(analysisExecutor) { barcodes ->
+                    barcodes.firstOrNull()?.displayValue?.let { code ->
+                        if (code.isNotEmpty() && code !in checkedBarcodes) {
+                            checkedBarcodes.add(code)
+                            if (QtAndroidController.decodeQrCode(code)) {
+                                scanner.close()
+                                barcodeScanner = null
+                                activity.runOnUiThread { stop() }
+                            }
                         }
                     }
                 }
-            }.addOnFailureListener {
-                Log.e(TAG, "QR process failed: ${it.message}")
-            }.addOnCompleteListener {
-                imageProxy.close()
-            }
+                .addOnFailureListener(analysisExecutor) {
+                    Log.e(TAG, "QR process failed: ${it.message}")
+                }
+                .addOnCompleteListener(analysisExecutor) {
+                    imageProxy.close()
+                }
         }
     }
 
@@ -142,6 +177,8 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
 
     fun stop() {
         activity.runOnUiThread {
+            imageAnalysisExecutor?.shutdown()
+            imageAnalysisExecutor = null
             try {
                 boundCamera?.cameraControl?.enableTorch(false)
             } catch (_: Exception) {
@@ -158,6 +195,12 @@ class PairingQrEmbeddedCamera(private val activity: AmneziaActivity) {
             previewView = null
 
             activity.window.setBackgroundDrawable(windowBgOpaque)
+            savedWindowFormat?.let { fmt ->
+                val lp = activity.window.attributes
+                lp.format = fmt
+                activity.window.attributes = lp
+                savedWindowFormat = null
+            }
         }
     }
 }

client/android/src/org/amnezia/vpn/PairingQrScanBracketPaths.kt

@@ -0,0 +1,106 @@
+package org.amnezia.vpn
+
+import android.graphics.Path
+import android.graphics.RectF
+import kotlin.math.PI
+import kotlin.math.atan2
+import kotlin.math.max
+import kotlin.math.min
+
+/**
+ * Stroked L-brackets for the pairing scan frame — port of iOS `amneziaScanBracketStrokePath`
+ * (`iosPairingQrOverlayWindow.mm`).
+ * corner: 0=TL, 1=TR, 2=BL, 3=BR.
+ */
+object PairingQrScanBracketPaths {
+
+    private fun Path.addCornerMinorArc(
+        cx: Float,
+        cy: Float,
+        r: Float,
+        sx: Float,
+        sy: Float,
+        ex: Float,
+        ey: Float
+    ) {
+        var asRad = atan2((sy - cy).toDouble(), (sx - cx).toDouble())
+        var aeRad = atan2((ey - cy).toDouble(), (ex - cx).toDouble())
+        while (aeRad - asRad > PI) {
+            aeRad -= 2.0 * PI
+        }
+        while (aeRad - asRad < -PI) {
+            aeRad += 2.0 * PI
+        }
+        val minor = aeRad - asRad
+        val startDeg = Math.toDegrees(asRad).toFloat()
+        val sweepDeg = Math.toDegrees(minor).toFloat()
+        addArc(RectF(cx - r, cy - r, cx + r, cy + r), startDeg, sweepDeg)
+    }
+
+    fun bracketStrokePath(corner: Int, x0: Float, y0: Float, s: Float, R: Float, L: Float, t: Float): Path {
+        val r = max(1.5f, R - t * 0.5f)
+        val p = Path()
+        val yy = y0 + t * 0.5f
+        val yyb = y0 + s - t * 0.5f
+        val xx = x0 + t * 0.5f
+        val xxb = x0 + s - t * 0.5f
+
+        when (corner) {
+            0 -> {
+                val cTLx = x0 + R
+                val cTLy = y0 + R
+                val sTLx = x0 + R
+                val sTLy = yy
+                val eTLx = xx
+                val eTLy = y0 + R
+                p.moveTo(x0 + R + L, yy)
+                p.lineTo(sTLx, sTLy)
+                p.addCornerMinorArc(cTLx, cTLy, r, sTLx, sTLy, eTLx, eTLy)
+                val yEndTL = min(y0 + R + L, y0 + s - R - t * 0.5f)
+                p.lineTo(xx, max(yEndTL, y0 + R + 2f))
+            }
+            1 -> {
+                val cTRx = x0 + s - R
+                val cTRy = y0 + R
+                val sTRx = x0 + s - R
+                val sTRy = yy
+                val eTRx = xxb
+                val eTRy = y0 + R
+                p.moveTo(x0 + s - R - L, yy)
+                p.lineTo(sTRx, sTRy)
+                p.addCornerMinorArc(cTRx, cTRy, r, sTRx, sTRy, eTRx, eTRy)
+                val yEndTR = min(y0 + R + L, y0 + s - R - t * 0.5f)
+                p.lineTo(xxb, max(yEndTR, y0 + R + 2f))
+            }
+            2 -> {
+                val cBLx = x0 + R
+                val cBLy = y0 + s - R
+                val sBLx = x0 + R
+                val sBLy = yyb
+                val eBLx = xx
+                val eBLy = y0 + s - R
+                p.moveTo(x0 + R + L, yyb)
+                p.lineTo(sBLx, sBLy)
+                p.addCornerMinorArc(cBLx, cBLy, r, sBLx, sBLy, eBLx, eBLy)
+                val yEndTopRef = max(min(y0 + R + L, y0 + s - R - t * 0.5f), y0 + R + 2f)
+                val yLegBL = y0 + s + y0 - yEndTopRef
+                p.lineTo(xx, yLegBL)
+            }
+            3 -> {
+                val cBRx = x0 + s - R
+                val cBRy = y0 + s - R
+                val sBRx = x0 + s - R
+                val sBRy = yyb
+                val eBRx = xxb
+                val eBRy = y0 + s - R
+                p.moveTo(x0 + s - R - L, yyb)
+                p.lineTo(sBRx, sBRy)
+                p.addCornerMinorArc(cBRx, cBRy, r, sBRx, sBRy, eBRx, eBRy)
+                val yEndTopRef = max(min(y0 + R + L, y0 + s - R - t * 0.5f), y0 + R + 2f)
+                val yLegBR = y0 + s + y0 - yEndTopRef
+                p.lineTo(xxb, yLegBR)
+            }
+        }
+        return p
+    }
+}

client/android/src/org/amnezia/vpn/PairingQrScanGeometry.kt

@@ -0,0 +1,240 @@
+package org.amnezia.vpn
+
+import android.graphics.Rect
+import android.graphics.RectF
+import com.google.mlkit.vision.barcode.common.Barcode
+import kotlin.math.floor
+import kotlin.math.max
+import kotlin.math.min
+
+/**
+ * Same proportions as [PageSettingsApiQrPairingSend.qml] (iOS embedded scan): sq = 0.72 * min(w,h),
+ * vertical bias -0.06 * height (square shifted up slightly).
+ */
+object PairingQrScanGeometry {
+    const val SQ_FRACTION = 0.72f
+    const val VERTICAL_BIAS = 0.06f
+
+    fun holeRectF(viewW: Int, viewH: Int): RectF {
+        val w = viewW.toFloat()
+        val h = viewH.toFloat()
+        val side = min(w, h) * SQ_FRACTION
+        val left = (w - side) / 2f
+        var top = (h - side) / 2f - h * VERTICAL_BIAS
+        top = max(0f, top)
+        var bottom = top + side
+        if (bottom > h) {
+            bottom = h
+        }
+        val adjSide = bottom - top
+        return RectF(left, top, left + adjSide, bottom)
+    }
+
+    /** ML Kit [Barcode] box is in [InputImage] pixel space (same as analysis frame WxH). */
+    fun barcodeCenterInPairingHole(imageW: Int, imageH: Int, barcode: Barcode): Boolean {
+        val box = barcode.boundingBox ?: return true
+        val r = holeRectF(imageW, imageH)
+        return r.contains(box.centerX().toFloat(), box.centerY().toFloat())
+    }
+
+    /**
+     * Maps a rectangle in [PreviewView] / overlay pixel space to [InputImage] pixel space,
+     * assuming the preview uses default FILL_CENTER scaling (same as typical CameraX [PreviewView]).
+     */
+    fun viewRectToInputImageRectFillCenter(
+        viewW: Int,
+        viewH: Int,
+        imageW: Int,
+        imageH: Int,
+        viewRect: RectF
+    ): RectF {
+        val scale = max(viewW / imageW.toFloat(), viewH / imageH.toFloat())
+        val drawLeft = (viewW - imageW * scale) / 2f
+        val drawTop = (viewH - imageH * scale) / 2f
+        return RectF(
+            (viewRect.left - drawLeft) / scale,
+            (viewRect.top - drawTop) / scale,
+            (viewRect.right - drawLeft) / scale,
+            (viewRect.bottom - drawTop) / scale
+        )
+    }
+
+    /** Pairing hole (same geometry as overlay) expressed in ML Kit / [InputImage] coordinates. */
+    fun pairingHoleInImageCoords(viewW: Int, viewH: Int, imageW: Int, imageH: Int): RectF {
+        val holeView = holeRectF(viewW, viewH)
+        return viewRectToInputImageRectFillCenter(viewW, viewH, imageW, imageH, holeView)
+    }
+
+    /**
+     * Rounded scan window corner radius — same formula as iOS `layoutScanOverlayGeometry` (`holeR`).
+     * [sidePx] is the scan square side in pixels.
+     */
+    fun pairingIosStyleHoleCornerRadiusPx(sidePx: Float, density: Float): Float {
+        val d = density
+        var holeR = min(28f * d, max(10f * d, sidePx * 0.056f))
+        val half = 0.5f * sidePx
+        holeR = min(holeR, max(6f * d, half - 2f * d))
+        return max(holeR, 1f)
+    }
+
+    /** Area(roi ∩ box) / area(box); 0 if disjoint. */
+    fun barcodeBoxOverlapFraction(roi: RectF, box: Rect): Float {
+        val bf = RectF(box)
+        val inter = RectF(roi)
+        if (!inter.intersect(bf)) return 0f
+        val interArea = inter.width() * inter.height()
+        val boxArea = bf.width() * bf.height()
+        return if (boxArea <= 0f) 0f else interArea / boxArea
+    }
+
+    /**
+     * Accept only codes whose bounding box overlaps the on-screen pairing square by at least
+     * [minOverlapFraction] when that square is mapped into image space (preview FILL_CENTER model).
+     */
+    fun barcodeMostlyInsidePairingHole(
+        viewW: Int,
+        viewH: Int,
+        imageW: Int,
+        imageH: Int,
+        barcode: Barcode,
+        minOverlapFraction: Float = 0.82f
+    ): Boolean {
+        val box = barcode.boundingBox ?: return true
+        if (viewW <= 0 || viewH <= 0 || imageW <= 0 || imageH <= 0) {
+            return barcodeCenterInPairingHole(imageW, imageH, barcode)
+        }
+        val roi = pairingHoleInImageCoords(viewW, viewH, imageW, imageH)
+        val inset = 0.02f * min(imageW, imageH)
+        roi.inset(inset, inset)
+        if (roi.width() <= 0f || roi.height() <= 0f) {
+            return barcodeCenterInPairingHole(imageW, imageH, barcode)
+        }
+        return barcodeBoxOverlapFraction(roi, box) >= minOverlapFraction
+    }
+
+    /**
+     * Pairing send: accept only if the QR lies fully inside the on-screen square.
+     * [roiInImageSpace] is [holeRectF] in [PreviewView] coords mapped into the same space as ML Kit
+     * geometry ([CoordinateTransform] in [CameraActivity]).
+     *
+     * When [Barcode.getCornerPoints] is present (typical for QR), all corners must lie inside the ROI —
+     * tighter than [BoundingBox], which is often padded.
+     * Otherwise falls back to bbox center inside ROI plus [minOverlapFraction] of bbox area inside ROI.
+     */
+    fun barcodeMatchesPairingHole(
+        roiInImageSpace: RectF,
+        imageW: Int,
+        imageH: Int,
+        barcode: Barcode,
+        minOverlapFraction: Float = PAIRING_SEND_MIN_OVERLAP_BBOX_FALLBACK
+    ): Boolean {
+        if (imageW <= 0 || imageH <= 0) {
+            return false
+        }
+        val roi = RectF(roiInImageSpace)
+        val iw = imageW.toFloat()
+        val ih = imageH.toFloat()
+        roi.left = max(0f, roi.left)
+        roi.top = max(0f, roi.top)
+        roi.right = min(iw, roi.right)
+        roi.bottom = min(ih, roi.bottom)
+        if (roi.width() <= 0f || roi.height() <= 0f) {
+            return false
+        }
+
+        val corners = barcode.cornerPoints
+        if (corners != null && corners.size >= 4) {
+            for (p in corners) {
+                if (!roi.contains(p.x.toFloat(), p.y.toFloat())) {
+                    return false
+                }
+            }
+            return true
+        }
+
+        val box = barcode.boundingBox ?: return false
+        val cx = box.centerX().toFloat()
+        val cy = box.centerY().toFloat()
+        if (!roi.contains(cx, cy)) {
+            return false
+        }
+        return barcodeBoxOverlapFraction(roi, box) >= minOverlapFraction
+    }
+
+    /** Bbox-only fallback when corner points are missing (unusual for QR). */
+    private const val PAIRING_SEND_MIN_OVERLAP_BBOX_FALLBACK = 0.72f
+
+    /**
+     * Native pairing scan hole — same rules as iOS `layoutScanOverlayGeometry` in
+     * `iosPairingQrOverlayWindow.mm` (0.72 × min side, header / bottom band clamps).
+     * [headerBottomPx] is the bottom edge of the chrome row in this view’s coordinate system.
+     */
+    fun pairingIosStyleHoleRectF(
+        viewW: Int,
+        viewH: Int,
+        headerBottomPx: Float,
+        statusBarTopPx: Float,
+        density: Float
+    ): RectF {
+        val w = viewW.toFloat()
+        val h = viewH.toFloat()
+        val d = density
+        if (w < 32f || h < 32f) {
+            return RectF()
+        }
+        var hdrBottom = headerBottomPx
+        if (hdrBottom < 8f * d) {
+            hdrBottom = 132f * d + statusBarTopPx
+        }
+        val sqSz = floor(min(w, h) * 0.72).toFloat()
+        var sqX = (w - sqSz) / 2f
+        var sqY = (h - sqSz) / 2f
+        sqY = max(sqY, hdrBottom + 8f * d)
+        val kBottomBand = 80f * d
+        val maxHoleBottom = h - kBottomBand
+        if (sqY + sqSz > maxHoleBottom) {
+            sqY = maxHoleBottom - sqSz
+            sqY = max(sqY, hdrBottom + 8f * d)
+        }
+        sqX = max(8f * d, min(sqX, w - sqSz - 8f * d))
+        sqY = max(hdrBottom + 4f * d, min(sqY, h - sqSz - 8f * d))
+        return RectF(sqX, sqY, sqX + sqSz, sqY + sqSz)
+    }
+
+    /**
+     * Vertical center of the torch control in px (same math as iOS `torchCenterYConstraint` update).
+     */
+    fun pairingIosStyleTorchCenterYPx(
+        holeBottomPx: Float,
+        bandBottomPx: Float,
+        headerBottomPx: Float,
+        safeBottomPx: Float,
+        density: Float
+    ): Float {
+        val torchH = 56f * density
+        val d = density
+        var torchCy = (holeBottomPx + bandBottomPx) * 0.5f
+        val minC = holeBottomPx + torchH * 0.5f + 6f * d
+        val maxC = bandBottomPx - torchH * 0.5f - max(6f * d, safeBottomPx)
+        torchCy = max(minC, min(maxC, torchCy))
+        if (minC > maxC) {
+            torchCy = (minC + maxC) * 0.5f
+        }
+        val hdr = headerBottomPx + torchH * 0.5f + 10f * d
+        return max(torchCy, hdr)
+    }
+
+    /** [pairingIosStyleHoleRectF] mapped with the legacy FILL_CENTER preview model (transform fallback). */
+    fun pairingIosStyleHoleInImageCoords(
+        viewW: Int,
+        viewH: Int,
+        headerBottomPx: Float,
+        statusBarTopPx: Float,
+        density: Float,
+        imageW: Int,
+        imageH: Int
+    ): RectF {
+        val hv = pairingIosStyleHoleRectF(viewW, viewH, headerBottomPx, statusBarTopPx, density)
+        return viewRectToInputImageRectFillCenter(viewW, viewH, imageW, imageH, hv)
+    }
+}

client/android/src/org/amnezia/vpn/PairingQrScanOverlayView.kt

@@ -0,0 +1,116 @@
+package org.amnezia.vpn
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.graphics.Path
+import android.graphics.RectF
+import android.util.AttributeSet
+import android.view.MotionEvent
+import android.view.View
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowInsetsCompat
+import kotlin.math.max
+
+/**
+ * iOS-style pairing scan chrome: dim outside a central square + white corner brackets.
+ * Hole layout matches iOS `layoutScanOverlayGeometry` ([pairingIosStyleHoleRectF]).
+ */
+class PairingQrScanOverlayView @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null,
+    defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+
+    init {
+        isClickable = false
+        isFocusable = false
+    }
+
+    /** Let taps reach [PreviewView] below for tap-to-focus. */
+    @Suppress("ClickableViewAccessibility")
+    override fun onTouchEvent(event: MotionEvent): Boolean = false
+
+    private val dimPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+        color = 0x8C000000.toInt() // ~55% black, same role as QML dimAlpha 0.55
+        style = Paint.Style.FILL
+    }
+
+    private val bracketPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+        color = 0xFFE8E8EC.toInt()
+        style = Paint.Style.STROKE
+        strokeCap = Paint.Cap.ROUND
+        strokeJoin = Paint.Join.ROUND
+    }
+
+    private var hole = RectF()
+
+    private val bracketPaths = arrayOfNulls<Path>(4)
+
+    private var pairingHeaderBottomPx = 0f
+
+    fun setPairingHeaderBottomPx(px: Float) {
+        if (pairingHeaderBottomPx == px) {
+            return
+        }
+        pairingHeaderBottomPx = px
+        recomputePairingHole()
+        invalidate()
+    }
+
+    private fun recomputePairingHole() {
+        val w = width
+        val h = height
+        if (w <= 0 || h <= 0) {
+            return
+        }
+        val topInset = ViewCompat.getRootWindowInsets(this)
+            ?.getInsets(WindowInsetsCompat.Type.statusBars())?.top?.toFloat() ?: 0f
+        val d = resources.displayMetrics.density
+        hole = PairingQrScanGeometry.pairingIosStyleHoleRectF(w, h, pairingHeaderBottomPx, topInset, d)
+        rebuildBracketPaths()
+    }
+
+    private fun rebuildBracketPaths() {
+        val s = hole.width()
+        if (s <= 0f) {
+            bracketPaths.fill(null)
+            return
+        }
+        val x0 = hole.left
+        val y0 = hole.top
+        val t = bracketPaint.strokeWidth
+        val d = resources.displayMetrics.density
+        val l = max(28f * d, s * 0.13f)
+        val r = PairingQrScanGeometry.pairingIosStyleHoleCornerRadiusPx(s, d)
+        for (i in 0..3) {
+            bracketPaths[i] = PairingQrScanBracketPaths.bracketStrokePath(i, x0, y0, s, r, l, t)
+        }
+    }
+
+    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
+        super.onSizeChanged(w, h, oldw, oldh)
+        bracketPaint.strokeWidth = max(3f, 5f * resources.displayMetrics.density)
+        recomputePairingHole()
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        super.onDraw(canvas)
+        val w = width.toFloat()
+        val h = height.toFloat()
+        val holeLeft = hole.left
+        val holeTop = hole.top
+        val holeRight = hole.right
+        val holeBottom = hole.bottom
+
+        // Four dim rects (same idea as QML dimLayer)
+        canvas.drawRect(0f, 0f, w, holeTop, dimPaint)
+        canvas.drawRect(0f, holeBottom, w, h, dimPaint)
+        canvas.drawRect(0f, holeTop, holeLeft, holeBottom, dimPaint)
+        canvas.drawRect(holeRight, holeTop, w, holeBottom, dimPaint)
+
+        for (i in 0..3) {
+            bracketPaths[i]?.let { canvas.drawPath(it, bracketPaint) }
+        }
+    }
+}

client/android/src/org/amnezia/vpn/qt/QtAndroidController.kt

@@ -36,4 +36,8 @@ object QtAndroidController {
     external fun onActivityResumed()
 
     external fun onCameraPermissionResult(granted: Boolean)
+
+    external fun onPairingQrCameraClosed()
+
+    external fun onPairingQrCameraUserDismissed()
 }

client/cmake/android.cmake

@@ -16,6 +16,45 @@ set_target_properties(${PROJECT} PROPERTIES
     QT_ANDROID_PACKAGE_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/android
 )
 
+# libQt6Core is built against a recent LLVM libc++; if androiddeployqt packs an older
+# libc++_shared.so (e.g. from NDK 25), dlopen fails on std::pmr::monotonic_buffer_resource.
+# Pin the STL to the same NDK CMake uses (Qt 6.9.x expects NDK r27 — see Qt wiki).
+if(CMAKE_ANDROID_NDK)
+    file(GLOB _amnz_ndk_prebuilts
+        LIST_DIRECTORIES true
+        "${CMAKE_ANDROID_NDK}/toolchains/llvm/prebuilt/*")
+    set(_amnz_ndk_prebuilt "")
+    foreach(_amnz_d IN LISTS _amnz_ndk_prebuilts)
+        if(IS_DIRECTORY "${_amnz_d}")
+            set(_amnz_ndk_prebuilt "${_amnz_d}")
+            break()
+        endif()
+    endforeach()
+    if(CMAKE_ANDROID_ARCH_ABI STREQUAL "arm64-v8a")
+        set(_amnz_libcxx_triple "aarch64-linux-android")
+    elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL "armeabi-v7a")
+        set(_amnz_libcxx_triple "armv7a-linux-androideabi")
+    elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL "x86")
+        set(_amnz_libcxx_triple "i686-linux-android")
+    elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL "x86_64")
+        set(_amnz_libcxx_triple "x86_64-linux-android")
+    else()
+        set(_amnz_libcxx_triple "")
+    endif()
+    if(_amnz_ndk_prebuilt AND _amnz_libcxx_triple)
+        set(_amnz_libcxx_shared
+            "${_amnz_ndk_prebuilt}/sysroot/usr/lib/${_amnz_libcxx_triple}/libc++_shared.so")
+        if(EXISTS "${_amnz_libcxx_shared}")
+            set_property(TARGET ${PROJECT} PROPERTY QT_ANDROID_EXTRA_LIBS "${_amnz_libcxx_shared}")
+            message(STATUS "Android: QT_ANDROID_EXTRA_LIBS libc++_shared from NDK: ${_amnz_libcxx_shared}")
+        else()
+            message(WARNING "Android: libc++_shared not found at ${_amnz_libcxx_shared} (check CMAKE_ANDROID_NDK=${CMAKE_ANDROID_NDK})")
+        endif()
+    else()
+        message(WARNING "Android: could not resolve NDK prebuilt under ${CMAKE_ANDROID_NDK}")
+    endif()
+endif()
+
 set(QT_ANDROID_MULTI_ABI_FORWARD_VARS "QT_NO_GLOBAL_APK_TARGET_PART_OF_ALL;CMAKE_BUILD_TYPE")
 
 # We need to include qtprivate api's

client/platforms/android/android_controller.cpp

@@ -105,7 +105,9 @@ bool AndroidController::initialize()
         {"onSystemBarsInsetsChanged", "(II)V", reinterpret_cast<void *>(onSystemBarsInsetsChanged)},
         {"onActivityPaused", "()V", reinterpret_cast<void *>(onActivityPaused)},
         {"onActivityResumed", "()V", reinterpret_cast<void *>(onActivityResumed)},
-        {"onCameraPermissionResult", "(Z)V", reinterpret_cast<void *>(onCameraPermissionResult)}
+        {"onCameraPermissionResult", "(Z)V", reinterpret_cast<void *>(onCameraPermissionResult)},
+        {"onPairingQrCameraClosed", "()V", reinterpret_cast<void *>(onPairingQrCameraClosed)},
+        {"onPairingQrCameraUserDismissed", "()V", reinterpret_cast<void *>(onPairingQrCameraUserDismissed)}
     };
 
     QJniEnvironment env;
@@ -243,6 +245,11 @@ void AndroidController::startQrReaderActivity()
     callActivityMethod("startQrCodeReader", "()V");
 }
 
+void AndroidController::startPairingQrReaderActivity()
+{
+    callActivityMethod("startPairingQrCodeReader", "()V");
+}
+
 void AndroidController::startPairingQrEmbeddedCamera()
 {
     callActivityMethod("startPairingQrEmbeddedCamera", "()V");
@@ -623,4 +630,22 @@ void AndroidController::onCameraPermissionResult(JNIEnv *env, jobject thiz, jboo
     emit AndroidController::instance()->cameraPermissionResult(static_cast<bool>(granted));
 }
 
+// static
+void AndroidController::onPairingQrCameraClosed(JNIEnv *env, jobject thiz)
+{
+    Q_UNUSED(env);
+    Q_UNUSED(thiz);
+
+    PairingUiController::notifyAndroidPairingQrCameraClosed();
+}
+
+// static
+void AndroidController::onPairingQrCameraUserDismissed(JNIEnv *env, jobject thiz)
+{
+    Q_UNUSED(env);
+    Q_UNUSED(thiz);
+
+    PairingUiController::notifyAndroidPairingQrCameraUserDismissed();
+}
+
 

client/platforms/android/android_controller.h

@@ -46,6 +46,7 @@ public:
     int getStatusBarHeight();
     int getNavigationBarHeight();
     void startQrReaderActivity();
+    void startPairingQrReaderActivity();
     void startPairingQrEmbeddedCamera();
     void stopPairingQrEmbeddedCamera();
     void setPairingQrEmbeddedTorch(bool enabled);
@@ -117,6 +118,8 @@ private:
     static void onActivityPaused(JNIEnv *env, jobject thiz);
     static void onActivityResumed(JNIEnv *env, jobject thiz);
     static void onCameraPermissionResult(JNIEnv *env, jobject thiz, jboolean granted);
+    static void onPairingQrCameraClosed(JNIEnv *env, jobject thiz);
+    static void onPairingQrCameraUserDismissed(JNIEnv *env, jobject thiz);
 
     template <typename Ret, typename ...Args>
     static auto callActivityMethod(const char *methodName, const char *signature, Args &&...args);

client/ui/controllers/api/pairingUiController.cpp

@@ -2,9 +2,11 @@
 
 #include <QCoreApplication>
 #include <QDataStream>
+#include <QDateTime>
 #include <QDebug>
 #include <QIODevice>
 #include <QMetaObject>
+#include <QPointer>
 #include <QRegularExpression>
 #include <QTimer>
 #include <QUuid>
@@ -96,6 +98,33 @@ bool tryDecodeLegacyChunkedPairingQrPayload(const QString &t, QString *outUuid)
     *outUuid = u.toString(QUuid::WithoutBraces);
     return true;
 }
+
+/**
+ * Extract a pairing session UUID from raw QR text without touching QObject / signals.
+ * Safe from CameraX / JNI threads while AmneziaActivity is stopped (Qt event loop may not run).
+ */
+QString extractPairingSessionUuidFromScanText(const QString &raw)
+{
+    const QString t = raw.trimmed();
+    if (t.startsWith(QStringLiteral("vpn://"), Qt::CaseInsensitive)) {
+        return {};
+    }
+    static const QRegularExpression reV4(QStringLiteral(
+            "[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}"));
+    const QRegularExpressionMatch m = reV4.match(t);
+    if (m.hasMatch()) {
+        return m.captured(0);
+    }
+    QString fromLegacy;
+    if (tryDecodeLegacyChunkedPairingQrPayload(t, &fromLegacy)) {
+        return fromLegacy;
+    }
+    const QUuid parsed = QUuid::fromString(t);
+    if (!parsed.isNull()) {
+        return parsed.toString(QUuid::WithoutBraces);
+    }
+    return {};
+}
 } // namespace
 
 #if defined(Q_OS_ANDROID)
@@ -113,6 +142,15 @@ bool PairingUiController::iosNativePairingQrOverlayBuild() const
 #endif
 }
 
+bool PairingUiController::androidNativePairingQrOverlayBuild() const
+{
+#if defined(Q_OS_ANDROID)
+    return true;
+#else
+    return false;
+#endif
+}
+
 PairingUiController::PairingUiController(PairingController *pairingController, ServersController *serversController,
                                          SubscriptionController *subscriptionController,
                                          SecureAppSettingsRepository *appSettingsRepository, QObject *parent)
@@ -173,7 +211,7 @@ void PairingUiController::openPairingQrScanner()
 {
 #if defined(Q_OS_ANDROID)
     qInfo() << "[PairingUi] openPairingQrScanner (Android native activity)";
-    AndroidController::instance()->startQrReaderActivity();
+    AndroidController::instance()->startPairingQrReaderActivity();
 #endif
 }
 
@@ -319,34 +357,18 @@ bool PairingUiController::applyScannedTextAsPairingUuid(const QString &raw)
 {
     const QString t = raw.trimmed();
     qInfo() << "[PairingUi] scan raw len=" << t.size();
-    if (t.startsWith(QStringLiteral("vpn://"), Qt::CaseInsensitive)) {
-        qInfo() << "[PairingUi] scan rejected: looks like vpn:// bundle, not session UUID";
+    const QString uuid = extractPairingSessionUuidFromScanText(raw);
+    if (uuid.isEmpty()) {
+        if (t.startsWith(QStringLiteral("vpn://"), Qt::CaseInsensitive)) {
+            qInfo() << "[PairingUi] scan rejected: looks like vpn:// bundle, not session UUID";
+        } else {
+            qInfo() << "[PairingUi] scan rejected: no session UUID recognized in payload";
+        }
         return false;
     }
-    static const QRegularExpression reV4(QStringLiteral(
-            "[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}"));
-    const QRegularExpressionMatch m = reV4.match(t);
-    if (m.hasMatch()) {
-        const QString uuid = m.captured(0);
-        qInfo() << "[PairingUi] scan accepted uuid=" << uuid.left(13) << "...";
-        emit pairingUuidFromScan(uuid);
-        return true;
-    }
-    QString fromLegacy;
-    if (tryDecodeLegacyChunkedPairingQrPayload(t, &fromLegacy)) {
-        qInfo() << "[PairingUi] scan accepted legacy chunked QR uuid=" << fromLegacy.left(13) << "...";
-        emit pairingUuidFromScan(fromLegacy);
-        return true;
-    }
-    const QUuid parsed = QUuid::fromString(t);
-    if (!parsed.isNull()) {
-        const QString canon = parsed.toString(QUuid::WithoutBraces);
-        qInfo() << "[PairingUi] scan accepted QUuid::fromString uuid=" << canon.left(13) << "...";
-        emit pairingUuidFromScan(canon);
-        return true;
-    }
-    qInfo() << "[PairingUi] scan rejected: no session UUID recognized in payload";
-    return false;
+    qInfo() << "[PairingUi] scan accepted uuid=" << uuid.left(13) << "...";
+    emit pairingUuidFromScan(uuid);
+    return true;
 }
 
 #if defined(Q_OS_ANDROID)
@@ -356,25 +378,65 @@ bool PairingUiController::tryConsumeAndroidQrScan(const QString &code)
         qWarning() << "[PairingUi] tryConsumeAndroidQrScan: no controller (g_pairingUiForAndroidQr null)";
         return false;
     }
-    PairingUiController *const ctl = g_pairingUiForAndroidQr;
-    bool consumed = false;
     const QString codeCopy = code;
-    QObject *const app = QCoreApplication::instance();
-    if (!app) {
+    // Parse on this thread: while CameraActivity is foreground, AmneziaActivity is stopped and the Qt
+    // event loop may not process BlockingQueuedConnection until the user returns — UI would lag behind.
+    if (extractPairingSessionUuidFromScanText(codeCopy).isEmpty()) {
         return false;
     }
-    // CameraActivity / ML Kit may invoke JNI from a non-Qt thread. Signals and QML must run on the Qt GUI thread.
-    QMetaObject::invokeMethod(
-            app,
-            [ctl, codeCopy, &consumed]() {
-                consumed = ctl->applyScannedTextAsPairingUuid(codeCopy);
-            },
-            Qt::BlockingQueuedConnection);
-    qInfo() << "[PairingUi] tryConsumeAndroidQrScan consumed=" << consumed << "rawLen=" << codeCopy.size();
-    return consumed;
+    PairingUiController *const ctl = g_pairingUiForAndroidQr;
+    QPointer<PairingUiController> ctlPtr(ctl);
+    QTimer::singleShot(0, ctl, [ctlPtr, codeCopy]() {
+        if (!ctlPtr) {
+            return;
+        }
+        ctlPtr->applyScannedTextAsPairingUuid(codeCopy);
+    });
+    qInfo() << "[PairingUi] tryConsumeAndroidQrScan: scheduled apply on Qt thread, rawLen=" << codeCopy.size();
+    return true;
+}
+
+void PairingUiController::notifyAndroidPairingQrCameraClosed()
+{
+    if (g_pairingUiForAndroidQr) {
+        g_pairingUiForAndroidQr->suppressAndroidNativePairingReaderStarts(2000);
+    }
+}
+
+void PairingUiController::notifyAndroidPairingQrCameraUserDismissed()
+{
+    if (!g_pairingUiForAndroidQr) {
+        return;
+    }
+    PairingUiController *const ctl = g_pairingUiForAndroidQr;
+    QPointer<PairingUiController> ptr(ctl);
+    QTimer::singleShot(0, ctl, [ptr]() {
+        if (!ptr) {
+            return;
+        }
+        emit ptr->pairingAndroidNativeQrScannerUserDismissed();
+    });
 }
 #endif
 
+void PairingUiController::suppressAndroidNativePairingReaderStarts(int ms)
+{
+    if (ms <= 0) {
+        return;
+    }
+#if defined(Q_OS_ANDROID)
+    const qint64 now = QDateTime::currentMSecsSinceEpoch();
+    const qint64 until = now + ms;
+    if (until <= m_androidPairingReaderCooldownUntilEpochMs) {
+        return;
+    }
+    m_androidPairingReaderCooldownUntilEpochMs = until;
+    emit androidPairingReaderCooldownUntilEpochMsChanged();
+#else
+    Q_UNUSED(ms);
+#endif
+}
+
 QVariantList PairingUiController::tvQrCodes() const
 {
     QVariantList list;

client/ui/controllers/api/pairingUiController.h

@@ -40,6 +40,14 @@ class PairingUiController : public QObject
                        embeddedPairingQrCameraActiveChanged)
     /** True only on iOS builds: use native UIWindow QR overlay (not Qt.platform.os, which can differ). */
     Q_PROPERTY(bool iosNativePairingQrOverlayBuild READ iosNativePairingQrOverlayBuild CONSTANT)
+    /** True only on Android builds: full-screen CameraActivity pairing scanner; QML hides duplicate scan chrome. */
+    Q_PROPERTY(bool androidNativePairingQrOverlayBuild READ androidNativePairingQrOverlayBuild CONSTANT)
+    /**
+     * Epoch ms until which QML should not call openPairingQrScanner again (after native CameraActivity closes).
+     * Android pairing flow only; always 0 on other platforms.
+     */
+    Q_PROPERTY(qint64 androidPairingReaderCooldownUntilEpochMs READ androidPairingReaderCooldownUntilEpochMs NOTIFY
+                       androidPairingReaderCooldownUntilEpochMsChanged)
 
 public:
     PairingUiController(PairingController *pairingController, ServersController *serversController,
@@ -62,6 +70,7 @@ public:
     int tvPairingUiPhase() const { return m_tvPairingUiPhase; }
     bool embeddedPairingQrCameraActive() const { return m_embeddedPairingQrCameraActive; }
     bool iosNativePairingQrOverlayBuild() const;
+    bool androidNativePairingQrOverlayBuild() const;
     Q_INVOKABLE void setEmbeddedPairingQrCameraActive(bool active);
     /** iOS: native dim strip height uses safe bottom + extraPt (see PageSettingsApiQrPairingSend scanDimBleedBottom). No-op elsewhere. */
     Q_INVOKABLE void syncIosEmbeddedPairingQrNativeBottomExtra(int extraPt);
@@ -72,6 +81,10 @@ public:
      */
     Q_INVOKABLE void refreshIosEmbeddedPairingQrChrome();
 
+    qint64 androidPairingReaderCooldownUntilEpochMs() const { return m_androidPairingReaderCooldownUntilEpochMs; }
+    /** Lengthens androidPairingReaderCooldownUntilEpochMs to at least now + ms (Android pairing; no-op elsewhere). */
+    Q_INVOKABLE void suppressAndroidNativePairingReaderStarts(int ms);
+
     /**
      * iOS: UIKit UIWindow QR scanner (see iosPairingQrOverlayWindow). Pass translated title/subtitle for native chrome.
      * No-op on other platforms.
@@ -83,6 +96,10 @@ public:
 
 #if defined(Q_OS_ANDROID)
     static bool tryConsumeAndroidQrScan(const QString &code);
+    /** JNI from CameraActivity onDestroy: avoid reopening native reader while camera HAL is still releasing. */
+    static void notifyAndroidPairingQrCameraClosed();
+    /** JNI before CameraActivity finish when user pressed back — Qt should reopen native scan (QML shell has no preview). */
+    static void notifyAndroidPairingQrCameraUserDismissed();
 #endif
 
 public slots:
@@ -132,10 +149,13 @@ signals:
     /** After requestPairingCameraAccess(): true if OS granted camera access. */
     void pairingCameraAccessFinished(bool granted);
     void embeddedPairingQrCameraActiveChanged();
+    void androidPairingReaderCooldownUntilEpochMsChanged();
     /** iOS native overlay scanner: payload was not a pairing session UUID (toast in QML). */
     void pairingSendQrScanRejectedInvalidPayload();
     /** Native overlay back chevron tapped — dismiss scanner and close page from QML. */
     void pairingIosNativeQrOverlayBackRequested();
+    /** Android CameraActivity: user pressed back — QML should exit pairing send (e.g. closePage), not reopen camera. */
+    void pairingAndroidNativeQrScannerUserDismissed();
 
 private:
     void setTvBusy(bool busy);
@@ -170,6 +190,7 @@ private:
     quint64 m_phoneSessionGeneration { 0 };
 
     bool m_embeddedPairingQrCameraActive = false;
+    qint64 m_androidPairingReaderCooldownUntilEpochMs = 0;
 };
 
 #endif // PAIRINGUICONTROLLER_H

client/ui/qml/Pages2/PageSettingsApiQrPairingSend.qml

@@ -25,9 +25,17 @@ PageType {
     /** iOS-only: full-screen UIKit UIWindow scanner (PairingUiController.iosNativePairingQrOverlayBuild — not Qt.platform.os). */
     readonly property bool useIosNativePairingQrOverlay: PairingUiController.iosNativePairingQrOverlayBuild
 
+    /** Android: full-screen CameraActivity — Qt cannot reliably composite CameraX under QML on some OEMs (e.g. Samsung). */
+    readonly property bool useAndroidNativePairingQrScanner: GC.isMobile() && Qt.platform.os === "android"
+    /** Android: iOS-like flow — titles and camera preview only in CameraActivity; QML hides duplicate scan chrome. */
+    readonly property bool useAndroidNativePairingQrOverlay: PairingUiController.androidNativePairingQrOverlayBuild
+                                                             && GC.isMobile()
+                                                             && Qt.platform.os === "android"
+
     /** Let dimming draw into window chrome (status bar + tab bar) when camera underlay is active. */
     readonly property bool extendScanDimToScreenEdges: GC.isMobile() && pairingWizardStep === 0
                                                      && PairingUiController.embeddedPairingQrCameraActive
+                                                     && !root.useAndroidNativePairingQrOverlay
     clip: !extendScanDimToScreenEdges
 
     /** QQuickWindow (not Item); do not type as Item — breaks binding on Qt 6. */
@@ -140,6 +148,8 @@ PageType {
     property bool awaitingCameraPermissionForScan: false
     property bool waitingSettingsReturnForScan: false
     property bool torchOn: false
+    /** Suppress double startActivity when StackView fires both Component.onCompleted and onVisibleChanged. */
+    property int _androidPairingReaderLastStartMs: 0
 
     Timer {
         id: pairingCameraKickTimer
@@ -171,9 +181,18 @@ PageType {
         if (!root.visible) {
             return
         }
+        /** Confirm step (or transition to it): never reopen native / embedded scanner from stray taps or visibility. */
+        if (root.pairingWizardStep !== 0) {
+            return
+        }
+        if (addDeviceConfirmNavigationScheduled) {
+            return
+        }
         console.warn("[PairingQrSend] startMobileScanner Qt.platform.os=", Qt.platform.os,
                        "iosNativePairingQrOverlayBuild=", PairingUiController.iosNativePairingQrOverlayBuild,
-                       "useIosNativePairingQrOverlay=", root.useIosNativePairingQrOverlay)
+                       "useIosNativePairingQrOverlay=", root.useIosNativePairingQrOverlay,
+                       "androidNativePairingQrOverlayBuild=", PairingUiController.androidNativePairingQrOverlayBuild,
+                       "useAndroidNativePairingQrOverlay=", root.useAndroidNativePairingQrOverlay)
         if (!PairingUiController.isPairingCameraAccessGranted()) {
             awaitingCameraPermissionForScan = true
             PairingUiController.requestPairingCameraAccess()
@@ -186,6 +205,23 @@ PageType {
             /** Do not run pairingCameraKickTimer here: restartCapture during first startRunning races the session (torch needs 2–3 taps). */
             return
         }
+        if (root.useAndroidNativePairingQrScanner) {
+            const coolUntil = PairingUiController.androidPairingReaderCooldownUntilEpochMs
+            if (Date.now() < coolUntil) {
+                console.warn("[PairingQrSend] startMobileScanner: skip (native camera cooldown), ms left=",
+                             (coolUntil - Date.now()))
+                return
+            }
+            const now = Date.now()
+            if (now - _androidPairingReaderLastStartMs < 700) {
+                console.warn("[PairingQrSend] startMobileScanner: skip duplicate Android CameraActivity within",
+                             (now - _androidPairingReaderLastStartMs), "ms")
+                return
+            }
+            _androidPairingReaderLastStartMs = now
+            PairingUiController.openPairingQrScanner()
+            return
+        }
         PairingUiController.embeddedPairingQrCameraActive = true
         if (root.useIosStyleNativeQrReader) {
             // Session must start here, not only after pairingCameraKickTimer (220ms), otherwise
@@ -249,13 +285,15 @@ PageType {
 
     onVisibleChanged: {
         if (visible) {
-            addDeviceConfirmNavigationScheduled = false
+            /** Only reset confirm flag on scan step; clearing it on confirm breaks guards if visible flickers. */
             if (pairingWizardStep === 0) {
+                addDeviceConfirmNavigationScheduled = false
                 Qt.callLater(startMobileScanner)
             }
         } else {
             pairingCameraKickTimer.stop()
             stopMobileScanner()
+            _androidPairingReaderLastStartMs = 0
             pairingWizardStep = 0
             waitingSettingsReturnForScan = false
             if (!keepPhonePairingInBackgroundOnClose && !PairingUiController.phonePairingBusy) {
@@ -268,6 +306,10 @@ PageType {
         if (pairingWizardStep !== 0) {
             stopMobileScanner()
         } else if (root.visible) {
+            /**
+             * Android native: use Qt.callLater like iOS — a multi-second Timer delay left the QML scan chrome
+             * visible with an empty (black) viewport until CameraActivity opened.
+             */
             Qt.callLater(startMobileScanner)
         }
     }
@@ -348,10 +390,31 @@ PageType {
     Item {
         anchors.fill: parent
 
+        /** Brief Qt backdrop + back while CameraActivity is starting (native holds title/instructions like iOS overlay). */
+        Rectangle {
+            anchors.fill: parent
+            visible: pairingWizardStep === 0 && root.useAndroidNativePairingQrOverlay
+            color: AmneziaStyle.color.midnightBlack
+            z: 1
+        }
+        BackButtonType {
+            visible: pairingWizardStep === 0 && root.useAndroidNativePairingQrOverlay
+            anchors.top: parent.top
+            anchors.topMargin: PageController.safeAreaTopMargin
+            anchors.left: parent.left
+            width: parent.width
+            z: 2
+            backButtonFunction: function() {
+                PageController.closePage()
+            }
+        }
+
         Item {
             id: scanStep
             anchors.fill: parent
-            visible: pairingWizardStep === 0
+            visible: pairingWizardStep === 0 && !root.useAndroidNativePairingQrOverlay
+            /** Extra guard: invisible alone can race one frame on some stacks; deny input off scan step. */
+            enabled: pairingWizardStep === 0 && !root.useAndroidNativePairingQrOverlay
 
             readonly property real sqSz: Math.floor(Math.min(width, height) * 0.72)
             readonly property real sqX: (width - sqSz) / 2
@@ -653,16 +716,16 @@ PageType {
             anchors.leftMargin: 0
             anchors.rightMargin: 0
             visible: pairingWizardStep === 1
+            z: 10
             spacing: 16
 
             BackButtonType {
                 Layout.topMargin: 20 + PageController.safeAreaTopMargin
                 Layout.leftMargin: 0
                 backButtonFunction: function() {
-                    PairingUiController.cancelAllPairingActivity()
-                    pairingWizardStep = 0
                     addDeviceConfirmNavigationScheduled = false
-                    Qt.callLater(startMobileScanner)
+                    pairingWizardStep = 0
+                    PairingUiController.cancelAllPairingActivity()
                 }
             }
 
@@ -714,10 +777,9 @@ PageType {
                 text: qsTr("Cancel")
 
                 clickedFunc: function() {
-                    PairingUiController.cancelAllPairingActivity()
-                    pairingWizardStep = 0
                     addDeviceConfirmNavigationScheduled = false
-                    Qt.callLater(startMobileScanner)
+                    pairingWizardStep = 0
+                    PairingUiController.cancelAllPairingActivity()
                 }
             }
 
@@ -736,7 +798,9 @@ PageType {
             }
             awaitingCameraPermissionForScan = false
             if (granted) {
-                startMobileScanner()
+                if (root.pairingWizardStep === 0) {
+                    startMobileScanner()
+                }
             } else {
                 waitingSettingsReturnForScan = true
                 showScanCameraDeniedDrawer()
@@ -750,9 +814,8 @@ PageType {
             addDeviceConfirmNavigationScheduled = true
             stopMobileScanner()
             PairingUiController.pendingPhonePairingUuid = uuid
-            Qt.callLater(function() {
-                pairingWizardStep = 1
-            })
+            /** Immediate step switch so scan chrome is not hit-testable for another frame (avoids reopening CameraActivity). */
+            pairingWizardStep = 1
         }
 
         function onPairingSendQrScanRejectedInvalidPayload() {
@@ -771,5 +834,16 @@ PageType {
             stopMobileScanner()
             PageController.closePage()
         }
+
+        /** Native CameraActivity back: leave pairing flow (same as iOS overlay back). Do NOT reopen scanner. */
+        function onPairingAndroidNativeQrScannerUserDismissed() {
+            if (!root.useAndroidNativePairingQrOverlay) {
+                return
+            }
+            stopMobileScanner()
+            PairingUiController.cancelAllPairingActivity()
+            addDeviceConfirmNavigationScheduled = false
+            PageController.closePage()
+        }
     }
 }