Fix qr code scanner when using multiwindow mode

app/src/main/AndroidManifest.xml

@@ -31,6 +31,11 @@
         android:windowSoftInputMode="adjustResize"
         tools:targetApi="33">
 
+        <activity
+            android:name=".QrCodeScannerActivity"
+            android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen"
+            android:exported="false" />
+
         <receiver
             android:name=".service.BootReceiver"
             android:enabled="true"

app/src/main/java/com/greenart7c3/nostrsigner/QrCodeScannerActivity.kt

@@ -0,0 +1,106 @@
+package com.greenart7c3.nostrsigner
+
+import android.Manifest
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.os.Bundle
+import android.util.Log
+import android.widget.Toast
+import androidx.activity.ComponentActivity
+import androidx.activity.result.contract.ActivityResultContracts
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.ResultPoint
+import com.journeyapps.barcodescanner.BarcodeCallback
+import com.journeyapps.barcodescanner.BarcodeResult
+import com.journeyapps.barcodescanner.DecoratedBarcodeView
+import com.journeyapps.barcodescanner.DefaultDecoderFactory
+
+class QrCodeScannerActivity : ComponentActivity() {
+    private lateinit var barcodeView: DecoratedBarcodeView
+    private var hasFailedToResumeCamera = false
+
+    private val cameraPermissionLauncher = registerForActivityResult(
+        ActivityResultContracts.RequestPermission(),
+    ) { isGranted ->
+        if (isGranted) {
+            setupScanner()
+        } else {
+            Toast.makeText(this, "Camera permission denied.", Toast.LENGTH_SHORT).show()
+            sendResultAndFinish(null)
+        }
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        if (hasCameraPermission()) {
+            setupScanner()
+        } else {
+            cameraPermissionLauncher.launch(Manifest.permission.CAMERA)
+        }
+    }
+
+    private fun hasCameraPermission(): Boolean {
+        return checkSelfPermission(Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED
+    }
+
+    private fun setupScanner() {
+        barcodeView = DecoratedBarcodeView(this).apply {
+            barcodeView.decoderFactory = DefaultDecoderFactory(listOf(BarcodeFormat.QR_CODE))
+            initializeFromIntent(intent)
+            decodeContinuous(object : BarcodeCallback {
+                override fun barcodeResult(result: BarcodeResult?) {
+                    result?.text?.let {
+                        sendResultAndFinish(it)
+                    }
+                }
+
+                override fun possibleResultPoints(resultPoints: MutableList<ResultPoint>?) {}
+            })
+        }
+
+        setContentView(barcodeView)
+        safeResumeScanner()
+    }
+
+    private fun safeResumeScanner() {
+        try {
+            barcodeView.resume()
+        } catch (e: Exception) {
+            Log.e("QrScanner", "Camera resume failed: ${e.message}")
+            if (!hasFailedToResumeCamera) {
+                hasFailedToResumeCamera = true
+                Toast.makeText(this, "Camera is in use by another app.", Toast.LENGTH_LONG).show()
+                barcodeView.postDelayed({
+                    sendResultAndFinish(null)
+                }, 1500)
+            }
+        }
+    }
+
+    override fun onResume() {
+        super.onResume()
+        if (::barcodeView.isInitialized && hasWindowFocus()) {
+            safeResumeScanner()
+        }
+    }
+
+    override fun onPause() {
+        super.onPause()
+        if (::barcodeView.isInitialized) {
+            barcodeView.pause()
+        }
+    }
+
+    override fun onWindowFocusChanged(hasFocus: Boolean) {
+        super.onWindowFocusChanged(hasFocus)
+        if (::barcodeView.isInitialized) {
+            if (hasFocus) safeResumeScanner() else barcodeView.pause()
+        }
+    }
+
+    private fun sendResultAndFinish(result: String?) {
+        setResult(RESULT_OK, Intent().putExtra("qr_result", result))
+        finish()
+    }
+}

app/src/main/java/com/greenart7c3/nostrsigner/ui/QrCodeScanner.kt

@@ -1,37 +1,27 @@
 package com.greenart7c3.nostrsigner.ui
 
+import android.content.Intent
 import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
-import androidx.lifecycle.compose.LocalLifecycleOwner
-import com.google.zxing.client.android.Intents
-import com.journeyapps.barcodescanner.ScanContract
-import com.journeyapps.barcodescanner.ScanOptions
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.ui.platform.LocalContext
+import com.greenart7c3.nostrsigner.QrCodeScannerActivity
 
 @Composable
-fun SimpleQrCodeScanner(onScan: (String?) -> Unit) {
-    val lifecycleOwner = LocalLifecycleOwner.current
+fun SimpleQrCodeScanner(
+    onScan: (String?) -> Unit,
+) {
+    val context = LocalContext.current
+    val launcher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.StartActivityForResult(),
+    ) { result ->
+        val text = result.data?.getStringExtra("qr_result")
+        onScan(text)
+    }
 
-    val qrLauncher =
-        rememberLauncherForActivityResult(ScanContract()) {
-            if (it.contents != null) {
-                onScan(it.contents)
-            } else {
-                onScan(null)
-            }
-        }
-
-    val scanOptions =
-        ScanOptions().apply {
-            setDesiredBarcodeFormats(ScanOptions.QR_CODE)
-            setPrompt("Point to the QR Code")
-            setBeepEnabled(false)
-            setOrientationLocked(false)
-            addExtra(Intents.Scan.SCAN_TYPE, Intents.Scan.MIXED_SCAN)
-        }
-
-    DisposableEffect(lifecycleOwner) {
-        qrLauncher.launch(scanOptions)
-        onDispose { }
+    LaunchedEffect(Unit) {
+        val intent = Intent(context, QrCodeScannerActivity::class.java)
+        launcher.launch(intent)
     }
 }