Membuat QR Code & Barcode Scanner dengan Flutter

import 'package:flutter/material.dart';
import 'package:scanner_qrcode/qrscanncode.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'QR Code Scanner',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: QrCodeScan(),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:barcode_scan/barcode_scan.dart';
import 'package:flutter/services.dart';

class QrCodeScan extends StatefulWidget {
  @override
  _QrCodeScanState createState() => _QrCodeScanState();
}

class _QrCodeScanState extends State<QrCodeScan> {
  String result = "Waiting QR Scan Text";
  Future _scanQR() async {
    try {
      String qrResult = await BarcodeScanner.scan();
       setState(() {
        result = qrResult;
      });
    } on PlatformException catch (ex) {
      if (ex.code == BarcodeScanner.CameraAccessDenied) {
        setState(() {
          result = "Camera permission denied";
        });
      } else {
        setState(() {
          result = "Unkown error $ex";
        });
      }
    } on FormatException {
      setState(() {
        result = "You pressed the back button before scanning anything";
      });
    }catch(e){
      setState(() {
        result = "Unkown error $e";
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(

      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
      appBar: AppBar(
        title: Text("QR Code Scanner"),
      ),
      body:Center(
        child:Column(

        mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
               Text(
                  result,
                  style: TextStyle(
                    fontSize: 30.0,
                    fontWeight: FontWeight.bold,
                  ), textAlign: TextAlign.center,
                 ),
        new SizedBox(
          height: 20.0,),
           new SizedBox(
             child: new RaisedButton(
                  onPressed: () {
            _scanQR();
          },
          textColor: Colors.white,
          child: Text('Scann QR CODE', style: TextStyle(fontSize: 20)),
          ),
                 )

        ],
      )

      )

    );
  }
}