MissingPluginException: MissingPluginException(No implementation found for method vision#startBarcodeScanner on channel g...

[sentry-io]

Sentry Issue: SMOOTHIE-T3

MissingPluginException: MissingPluginException(No implementation found for method vision#startBarcodeScanner on channel google_ml_barcode_scanner)
  File "barcode_scanner.dart", line 21, in BarcodeScanner.processImage
  File "ml_kit_scan_page.dart", line 226, in MLKitScannerPageState._processCameraImage

[cli1005]

Issue has been reproduced on my mobile phone iOS (launched locally with current code, not via TestFlight), which might be caused by the package google_ml_barcode_scanner, since I manage to scan continuously by switching to google_ml_kit(0.7.3), but configuration of Firebase in Podfile and AppDelegated.swift are necessary to make it work.

google_ml_barcode_scanner might be an old version of GoogleMLKit/BarcodeScanning, more détails could be found as followings:

• MissingPluginException No implementation found for method listen on channel flutter-ml/google_ml_kit_flutter#8
• [iOS] App is crashing with "uncaught exception FIRAppNotConfigured" when trying to scan barcode flutter-ml/google_ml_kit_flutter#172

[M123-dev]

Thanks for sharing @cli1005, yes google_ml_barcode_scanner is indeed a version of google_ml_kit but it excluded all the other ML-Kit features in favour of the app size. Did you test google_ml_barcode_scanner with Firebase set up, this would save a lot time

[monsieurtanuki]

@M123-dev I've lost the thread, but I believe that currently we support 2 different scanners. I assume that it was for good reasons, e.g. the first one not working properly or the second proposing interesting features.
Could we imagine to use scanner 1 for Android and scanner 2 for iOS, given the stack of issues, or is it never as simple as "scanner x always works on platform y but not always on platform z"?

[M123-dev]

@monsieurtanuki when I remeber right then both had some flaws on iOS, the old one's github repo (of the native library used) is archived so no bug fixes there, the best thing would be to fix this one here. The problem is just that I have no way to debug/reproduce so it's mostly about guessing

[monsieurtanuki]

@M123-dev Understood. What about trying mobile_scanner (39 likes, 130 pub points, 82% popularity), which is very active ("published 5 days ago") and seems to be focusing on barcodes using ml? It sounds better than google_ml_barcode_scanner (1 like, 120 pub points, 71% popularity, published 4 months ago"), doesn't it?

[M123-dev]

@monsieurtanuki sadly it's not as easy as that since we need a lot of customization. I did a comparison in January which can be found here

As for mobile_scanner it uses ML-Kit which is certainly good for performance but doesn't support much customization out of the box, also it's just 21 days old (Feb 8) thats why it's not in the comparison

For google_ml_barcode_scanner it doesn't have much likes since it's a fork of google_ml_kit (301 likes, 130 points, 97%). The problem with using it is just that it supports nearly all ML-Kit features, so it includes all native ML-Kit libraries which increases the app by size a lot

[monsieurtanuki]

@M123-dev Thank you for your explanations.

For google_ml_barcode_scanner it doesn't have much likes since it's a fork of google_ml_kit (301 likes, 130 points, 97%).

I guess that if developers used it and found it remotely interesting, it would have more than 1 like after more than 4 months... There are only 2 releases in google_ml_barcode_scanner:

• 0.0.1 Initial release
• 0.0.2 Added missing exports (4 months ago)

That's not what I call a very active project.

On the other hand, the more recent mobile_scanner is much more dynamic - obviously there was room in pub.dev for a decent barcode scanner. I'm sure its maintainer would be more than interested in new feature suggestions.

Those were just remarks from an external viewpoint.

[cli1005]

Thanks for sharing @cli1005, yes google_ml_barcode_scanner is indeed a version of google_ml_kit but it excluded all the other ML-Kit features in favour of the app size. Did you test google_ml_barcode_scanner with Firebase set up, this would save a lot time

Yes, I modified the file ios/Podfile, ios/Runner/AppDelegate.swift, and added a plist file GoogleServices-Info.pist in ios/Runner folder as mentioned in this reply : flutter-ml/google_ml_kit_flutter#172 (comment)

• ios/Podfile

...
target 'Runner' do
use_frameworks!
use_modular_headers!
pod 'Firebase'
flutter_install_all_ios_pods File.dirname(File.realpath(FILE))
end
...

• ios/Runner/AppDelegate.swift

...
import Firebase
...
GeneratedPluginRegistrant.register(with: self)
FirebaseApp.configure()
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
...

• GoogleServices-Info.plist
  I use a plist file of my personal firebase project, it seems that the content of this file is not important, so you could follow steps in this link https://firebase.google.com/docs/ios/setup to get un plist file.

It seems that firebase dependencies could be removed from ML kit, but it does not work with the version 0.7.3(tried 💪 => failed 😞 ):

• According to Doc ML Kit, we could remove firebase dependencies:
  https://developers.google.com/ml-kit/migration/ios?hl=en#remove_firebase_dependencies_optional
• But Issues still open, newest created 13/01/2022:
  https://github.com/bharat-biradar/Google-Ml-Kit-plugin/search?q=Firebase+app+has+not+yet+been+configure&type=issues

[M123-dev]

That's unfortunate @cli1005 but I am unsure what this is caused by.

The package doesn't include the old firebase scanner (Firebase/MLVision or Firebase/MLVisionBarcodeModel) but only the new mlkit barcode scanner (GoogleMLKit/BarcodeScanning) and on the official guide for it there is nothing about adding a firebase project. https://developers.google.com/ml-kit/vision/barcode-scanning/ios?hl=en

So its likely a problem of the implementation inside the package and not from ml kit.

Best would be if we could find a way to fix it otherwise we would have to add a firebase project

[M123-dev]

I found another intersting fact, 85.96% of the occurrences happen on iOS simulator. But since we stopped sentry for debug builds a bit ago they stopped coming in. But there are still some reports coming in from real devices

[cli1005]

I made a fix in method handler of google_ml_barcode_scanner, we might use the git repo forked while waiting for my PR to be merged:

google_ml_barcode_scanner:
git:
url: https://github.com/cli1005/google_ml_barcode_scanner.git
ref: master

[M123-dev]

Heyy sounds great @cli1005 you know if this problem also exists in the main google_ml_kit package

[M123-dev]

Opened a PR @cli1005

[cli1005]

I tested the newest version released on TestFlight, it works on my mobile(iOS15.3), does it work on yours?