MlKitContext has not been initialized

[Tareq-Ghassan]

I am using it on both Android and IOS, on IOS it works fines! But on Android after run the app it gives an exception in Logcat and when I open the scanner it don't open the camera preview.

this is how my preview looks like:

this is the exception am facing:

Error registering plugin mobile_scanner, dev.steenbakker.mobile_scanner.MobileScannerPlugin java.lang.IllegalStateException: MlKitContext has not been initialized at com.google.android.gms.common.internal.Preconditions.checkState(com.google.android.gms:play-services-basement@@18.2.0:2) at com.google.mlkit.common.sdkinternal.MlKitContext.getInstance(com.google.mlkit:common@@18.9.0:1) at com.google.mlkit.vision.barcode.BarcodeScanning.getClient(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.3.0:1) at dev.steenbakker.mobile_scanner.MobileScanner.(MobileScanner.kt:52) at dev.steenbakker.mobile_scanner.MobileScannerHandler.(MobileScannerHandler.kt:85) at dev.steenbakker.mobile_scanner.MobileScannerPlugin.onAttachedToActivity(MobileScannerPlugin.kt:24) at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.add(FlutterEngineConnectionRegistry.java:157) at io.flutter.plugins.GeneratedPluginRegistrant.registerWith(GeneratedPluginRegistrant.java:79) at java.lang.reflect.Method.invoke(Native Method) at io.flutter.embedding.engine.plugins.util.GeneratedPluginRegister.registerGeneratedPlugins(GeneratedPluginRegister.java:80) at io.flutter.embedding.android.FlutterFragmentActivity.configureFlutterEngine(FlutterFragmentActivity.java:743) at com.bankofjordan.mobileapp.MainActivity.configureFlutterEngine(MainActivity.kt:80) at io.flutter.embedding.android.FlutterFragment.configureFlutterEngine(FlutterFragment.java:1531) at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onAttach(FlutterActivityAndFragmentDelegate.java:213) at io.flutter.embedding.android.FlutterFragment.onAttach(FlutterFragment.java:1062) at androidx.fragment.app.Fragment.performAttach(Fragment.java:3068) at androidx.fragment.app.FragmentStateManager.attach(FragmentStateManager.java:490) at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:265) at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:1943) at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:1839) at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1782) at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3042) at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:2952) at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:263) at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:350) at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1582) at android.app.Activity.performStart(Activity.java:8977) at android.app.ActivityThread.handleStartActivity(ActivityThread.java:4198) at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:225) at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:205) at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:177) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:98) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2685) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loopOnce(Looper.java:230) at android.os.Looper.loop(Looper.java:319) at android.app.ActivityThread.main(ActivityThread.java:8893) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:608) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1103)

[Odaykhz]

I'm experiencing the same issue as described. The app functions correctly on iOS, but on Android, it encounter an exception upon launch as indicated by the Logcat error. Additionally, the scanner feature fails to initiate the camera preview. Is there any update or potential fix for this problem?

[navaronbracke]

Do you have the following information? 1) The Flutter version that you use 2) The version of mobile_scanner 3) A minimal code sample to reproduce the error

[Tareq-Ghassan]

Sure!

• My Flutter version is 3.19.5
• mobile_scanner version: 4.0.1

class CliQQRScanner extends StatefulWidget {
  const CliQQRScanner({super.key});

  @override
  State<CliQQRScanner> createState() => CliQQRScannerState();
}

class CliQQRScannerState extends State<CliQQRScanner> {
  @override
  void dispose() {
    cameraScanner.dispose();
    super.dispose();
  }

  void decodQR(BarcodeCapture barcodeCapture) {
    final List<Barcode> code = barcodeCapture.barcodes;
    debugPrint('Barcode found! ${code[0].rawValue}');
    Provider.of<CliQProvider>(context, listen: false)
        .parseQR(context, emvstring: code[0].rawValue!);
  }

  MobileScannerController cameraScanner = MobileScannerController(
      detectionSpeed: DetectionSpeed.noDuplicates,
      formats: [
        BarcodeFormat.qrCode,
      ]);
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: MobileScanner(
        controller: cameraScanner,
        onDetect: decodQR,
      ),
    );
  }
}

knowing that the exception happens before I even reach the screen

[Baseljamal]

Facing the same issue here!

[navaronbracke]

I did a bit of digging and in this thread https://github.com/googlesamples/mlkit/issues/264 there is a discussion about an MLKit <provider> tag in the merged Android Manifest.

The mobile_scanner example app does receive this provider:

Do you have such a provider in your application's merged Manifest? Do you manually initialize MLKit in your native Android code? (for example in your Activity?)

[Tareq-Ghassan]

I've already tried this solution before and added it to my Android Manifest under the tag, but it didn't work.

In my native Android, I've only included method channels that I created, none of which use MLKit. Therefore, I haven't manually initialized MLKit

[navaronbracke]

Which version of MLKit are you using? The provider I listed above has the exported=false annotation (which is required for more recent versions of Android), while yours does not. I also think that the tools:node="remove" on your provider means that the MLKit provider that automatically initializes the MLKit context might get removed in the actual application binary?

Which would explain your issue, since then neither the provider or your own code initializes MLKit?

[navaronbracke]

@Tareq-Ghassan The tools:node="remove" indeed disables the automatic initialization it seems.

See this documentation https://developers.google.com/android/reference/com/google/mlkit/common/MlKit#public-methods The line How to disable ML Kit initialization content provider: provides a code sample like

<provider
   android:name="com.google.mlkit.common.internal.MlKitInitProvider"
   android:authorities="${applicationId}.mlkitinitprovider"
   tools:node="remove" />

You'll have to call that initialize(Context context) method manually in your Application's onCreate() then.

We should probably document this in mobile_scanner's README.

[Tareq-Ghassan]

@navaronbracke I modified my provider to this

<provider android:name="com.google.mlkit.common.internal.MlKitInitProvider" android:exported="false" android:authorities="${applicationId}.mlkitinitprovider" />

and now I had a different error

Error registering plugin mobile_scanner, dev.steenbakker.mobile_scanner.MobileScannerPlugin
                 java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.mlkit.vision.barcode.internal.BarcodeScannerImpl com.google.mlkit.vision.barcode.internal.zzg.zza()' on a null object reference
                    at com.google.mlkit.vision.barcode.BarcodeScanning.getClient(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.3.0:1)
                    at dev.steenbakker.mobile_scanner.MobileScanner.<init>(MobileScanner.kt:52)
                    at dev.steenbakker.mobile_scanner.MobileScannerHandler.<init>(MobileScannerHandler.kt:85)
                    at dev.steenbakker.mobile_scanner.MobileScannerPlugin.onAttachedToActivity(MobileScannerPlugin.kt:24)
                    at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.add(FlutterEngineConnectionRegistry.java:157)
                    at io.flutter.plugins.GeneratedPluginRegistrant.registerWith(GeneratedPluginRegistrant.java:79)
                    at java.lang.reflect.Method.invoke(Native Method)
                    at io.flutter.embedding.engine.plugins.util.GeneratedPluginRegister.registerGeneratedPlugins(GeneratedPluginRegister.java:80)
                    at io.flutter.embedding.android.FlutterFragmentActivity.configureFlutterEngine(FlutterFragmentActivity.java:743)
                    at com.bankofjordan.mobileapp.MainActivity.configureFlutterEngine(MainActivity.kt:82)
                    at io.flutter.embedding.android.FlutterFragment.configureFlutterEngine(FlutterFragment.java:1531)
                    at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onAttach(FlutterActivityAndFragmentDelegate.java:213)
                    at io.flutter.embedding.android.FlutterFragment.onAttach(FlutterFragment.java:1062)
                    at androidx.fragment.app.Fragment.performAttach(Fragment.java:3068)
                    at androidx.fragment.app.FragmentStateManager.attach(FragmentStateManager.java:490)
                    at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:265)
                    at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:1943)
                    at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:1839)
                    at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1782)
                    at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3042)
                    at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:2952)
                    at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:263)
                    at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:350)
                    at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1582)
                    at android.app.Activity.performStart(Activity.java:8628)
                    at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3807)
                    at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:225)
                    at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:205)
                    at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:177)
                    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:98)
                    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2443)
                    at android.os.Handler.dispatchMessage(Handler.java:106)
                    at android.os.Looper.loopOnce(Looper.java:205)
                    at android.os.Looper.loop(Looper.java:294)
                    at android.app.ActivityThread.main(ActivityThread.java:8177)
                    at java.lang.reflect.Method.invoke(Native Method)
                    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

[Samuel-Fipps]

Any updates on this? It seems a lot of people are having this issue and I can tell you it only happens on some android phones not all. I get it on my note9 and not my s21.

[navaronbracke]

I guess what we could do is invoke the MLKitContext.initiliazeIfNeeded() when we start the scanner. However, we would need access to the Context for that.

It seems a lot of people are having this issue

I am unsure if that is because they disabled the automatic init provider or not, since the basic example does work without issues.

[Tareq-Ghassan]

Hi @navaronbracke

Am using now the latest version

mobile_scanner: ^5.1.1

and still facing the same issue

Attempt to invoke virtual method 'com.google.mlkit.vision.barcode.internal.BarcodeScannerImpl com.google.mlkit.vision.barcode.internal.zzg.zza()' on a null object reference

Kindly any update??

[dsouksavatd]

After spending two days troubleshooting, I resolved the issue by removing <application android:requestLegacyExternalStorage="true"/> from the AndroidManifest.xml. Everything works perfectly now!