Fix QRCode scanner

app/src/main/java/io/nekohasekai/sfa/ui/profile/QRScanActivity.kt

@@ -62,8 +62,8 @@ class QRScanActivity : AbstractActivity<ActivityQrScanBinding>() {
             } else {
                 setResult(RESULT_CANCELED)
                 finish()
+            }
         }
-    }
 
     private lateinit var imageAnalysis: ImageAnalysis
     private lateinit var imageAnalyzer: ImageAnalysis.Analyzer
@@ -75,10 +75,21 @@ class QRScanActivity : AbstractActivity<ActivityQrScanBinding>() {
     }
     private val onFailure: (Exception) -> Unit = {
         lifecycleScope.launch {
-            errorDialogBuilder(it).show()
+            resetAnalyzer()
+            errorDialogBuilder("MLKit error: ${it.localizedMessage}").show()
         }
     }
     private val vendorAnalyzer = Vendor.createQRCodeAnalyzer(onSuccess, onFailure)
+    private var useVendorAnalyzer = vendorAnalyzer != null
+    private fun resetAnalyzer() {
+        if (useVendorAnalyzer) {
+            useVendorAnalyzer = false
+            imageAnalysis.clearAnalyzer()
+            imageAnalyzer = ZxingQRCodeAnalyzer(onSuccess, onFailure)
+            imageAnalysis.setAnalyzer(analysisExecutor, imageAnalyzer)
+        }
+    }
+
     private lateinit var cameraProvider: ProcessCameraProvider
     private lateinit var cameraPreview: Preview
     private lateinit var camera: Camera
@@ -146,11 +157,19 @@ class QRScanActivity : AbstractActivity<ActivityQrScanBinding>() {
         finish()
     }
 
+    override fun onPrepareOptionsMenu(menu: Menu?): Boolean {
+        if (!useVendorAnalyzer) {
+            menu!!.findItem(R.id.action_use_vendor_analyzer).also {
+                it.isEnabled = false
+                it.isChecked = false
+            }
+        }
+        return true
+    }
+
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         menuInflater.inflate(R.menu.qr_scan_menu, menu)
-        if (vendorAnalyzer == null) {
-            menu.findItem(R.id.action_use_vendor_analyzer).isEnabled = false
-        } else {
+        if (useVendorAnalyzer) {
             menu.findItem(R.id.action_use_vendor_analyzer).isChecked = true
         }
         return true