Error when running the sample example

[ir2pid]

Flutter channel beta

[VERBOSE-2:ui_dart_state.cc(157)] Unhandled Exception: PlatformException(unregistered_view_type, trying to create a view with an unregistered type, unregistered view type: 'document_scanner')
#0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
#1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
<asynchronous suspension>
#2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
#3      AndroidViewController._create (package:flutter/src/services/platform_views.dart:633:54)
#4      AndroidViewController.setSize (package:flutter/src/services/platform_views.dart:550:14)
#5      RenderAndroidView._sizePlatformView (package:flutter/src/rendering/platform_view.dart:175:29)
#6      RenderAndroidView.performResize (package:flutter/src/rendering/platform_view.dart:156:5)
#7      RenderObject.layout (package:flutter/src/rendering/object.dart:1746:9)
#8      RenderProxyBoxMixin.performL<…>

import 'dart:io';

import 'dart:async';
import 'package:flutter/services.dart';
import 'package:Annoted/layers/util.dart';
import 'package:Annoted/util_ui.dart';
import 'package:document_scanner/document_scanner.dart';
import 'package:flutter/material.dart';
import 'package:Annoted/constants.dart';

class DocumentPage extends StatefulWidget {
  static String tag = 'document-page';
  final String title;

  DocumentPage({Key key, this.title}) : super(key: key);

  @override
  _DocumentPageState createState() => _DocumentPageState();
}

class _DocumentPageState extends State<DocumentPage> {
  String imageLocation;
  bool enableTorch;
  _DocumentPageState() {}

  @override
  Widget build(BuildContext context) {
    print("Widget build _DocumentPageState");
    //final Map<String, String> args = ModalRoute.of(context).settings.arguments;
    //String noteId = args["noteId"];
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
            leading: UtilUI.getIcon(Icons.arrow_back_ios, util.getTheme(context).accentColor, constants.d24, callback: () => {done(context)}),
            title: UtilUI.getTextH1(constants.sTab2, constants, util.getTheme(context).accentColor)),
        floatingActionButton: FloatingActionButton(
            child: Icon(!enableTorch ? Icons.flash_on : Icons.flash_off),
            onPressed: () {
              setState(() {
                enableTorch = !enableTorch;
              });
            }),
        body: Stack(
          children: <Widget>[
            Column(
              children: <Widget>[
                Expanded(
                  child: imageLocation != null
                      ? Image(image: FileImage(File.fromUri(Uri.file(imageLocation))))
                      : DocumentScanner(
                          onPictureTaken: (String image) {
                            print("document : " + image);

                            setState(() {
                              imageLocation = image.replaceRange(0, 7, "");
                              // imageLocation = image;
                            });

                            print("document : " + imageLocation);
                          },
                          brightness: 5,
                          contrast: 1.3,
                          enableTorch: enableTorch,
                        ),
                ),
              ],
            ),
            imageLocation != null
                ? Positioned(
                    bottom: 20,
                    left: 0,
                    right: 0,
                    child: RaisedButton(
                        child: Text("retry"),
                        onPressed: () {
                          setState(() {
                            imageLocation = null;
                          });
                        }),
                  )
                : Container(),
          ],
        ),
      ),
    );
  }

  @override
  void initState() {
    enableTorch = false;
    super.initState();
  }

  @override
  void dispose() {
    super.dispose();
  }

  done(BuildContext context) {
    util.navigatePop(context, {"note": null});
  }
}

[eliasteeny]

This issue should be addressed in the latest version.