'List<dynamic>' is not a subtype of type 'Map<dynamic, dynamic>'

[eimantas1998]

Hello, when i try to scan the first time everything works as expected, but when i try to do it again i get this error on a loop.

I/flutter (13206): type 'List<dynamic>' is not a subtype of type 'Map<dynamic, dynamic>' in type cast, #0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:321:56)
I/flutter (13206): <asynchronous suspension>
I/flutter (13206): #1      MethodChannel.invokeMapMethod (package:flutter/src/services/platform_channel.dart:349:48)
I/flutter (13206): #2      TextRecognizer.processImage (package:firebase_ml_vision/src/text_recognizer.dart:40:38)
I/flutter (13206): #3      _detect (package:flutter_camera_ml_vision/utils.dart:43:25)
I/flutter (13206): #4      CameraMlVisionState._processImage (package:flutter_camera_ml_vision/flutter_camera_ml_vision.dart:285:19)
I/flutter (13206): #5      CameraController.startImageStream.<anonymous closure> (package:camera/camera.dart:411:20)
I/flutter (13206): #6      _rootRunUnary (dart:async/zone.dart:1134:38)
I/flutter (13206): #7      _CustomZone.runUnary (dart:async/zone.dart:1031:19)
I/flutter (13206): #8      _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
I/flutter (13206): #9      _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:338:11)
I/flutter (13206): #10     _DelayedData.perform (dart:async/stream_impl.dart:593:14)
I/flutter (13206): #11     _StreamImplEvents.handleNext (dart:async/stream_impl.dart:709:11)
I/flutter (13206): #12     _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:669:7)
I/flutter (13206): #13     _rootRun (dart:async/zone.dart:1122:38)
I/flutter (13206): #14     _CustomZone.run (dart:async/zone.dart:1023:19)
I/flutter (13206): #15     _CustomZone.runGuarded (dart:async/zone.dart:925:7)
I/flutter (13206): #16     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965:23)
I/flutter (13206): #17     _rootRun (dart:async/zone.dart:1126:13)
I/flutter (13206): #18     _CustomZone.run (dart:async/zone.dart:1023:19)
I/flutter (13206): #19     _CustomZone.runGuarded (dart:async/zone.dart:925:7)
I/flutter (13206): #20     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965:23)
I/flutter (13206): #21     _microtaskLoop (dart:async/schedule_microtask.dart:43:21)
I/flutter (13206): #22     _startMicrotaskLoop (dart:async/schedule_microtask.dart:52:5)

[jaumard]

Hello,

Would be nice to have a reproducible code we can copy / paste to reproduce this issue. I use it and don't have this problem, so maybe a detector I didn't use yet or a config issue.

Thanks

[eimantas1998]

icon: Icon(Icons.photo_camera),
onPressed: () async {
String result =
await Navigator.of(context).push(
MaterialPageRoute(
builder: (c) {
return ScanPage(
regPattern: pattern);
},
),
);
if ((result ?? '').isNotEmpty) {
_controller.text = result;
}

class ScanPage extends StatefulWidget {
final String regPattern;

ScanPage({@required this.regPattern});

@OverRide
_ScanPageState createState() => _ScanPageState();
}

class _ScanPageState extends State {
TextRecognizer textRecognizer;

bool resultSent = false;

@OverRide
void initState() {
super.initState();
textRecognizer = FirebaseVision.instance.textRecognizer();
}

@OverRide
void dispose() {
textRecognizer.close();
super.dispose();
}

@OverRide
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Scanner'),
),
body: SafeArea(
child: SizedBox(
width: MediaQuery.of(context).size.width,
height: MediaQuery.of(context).size.height,
child: CameraMlVision(
resolution: ResolutionPreset.medium,
detector: textRecognizer.processImage,
onResult: (VisionText visionText) {
String matchedText = findMatch(visionText?.blocks ?? []);
if (matchedText.isNotEmpty && mounted && !resultSent) {
setState(() {
resultSent = true;
});
Navigator.of(context).pop(matchedText);
}
},
))),
);
}

String findMatch(List textBlocks) {
RegExp exp = new RegExp(widget.regPattern);

String wholeText = "";
for (TextBlock block in textBlocks) {
  block.lines.forEach((ln) => wholeText += "/" + ln.text);
}

if (exp.hasMatch(wholeText)) {
  return exp.stringMatch(wholeText);
} else {
  return '';
}

}
}

[eimantas1998]

To reproduce the issue try to get the result, or press back button, then try to scan again. After that it just starts looping the error.