New Example - QR Code Scanner (#122)

Co-authored-by: Mridul <mridul@Mriduls-MacBook-Pro.local>

scan_qr_code/lib/main.dart

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+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+import 'package:scan_qr_code/utils/qr_code_scanner.dart';
+import 'package:scan_qr_code/utils/scanner_box_border_painter.dart';
+
+void main() => runApp(const MyApp());
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: 'Code Scanner',
+      home: MyHomePage(title: 'Code Scanner Demo'),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  const MyHomePage({super.key, required this.title});
+
+  final String title;
+
+  @override
+  State<MyHomePage> createState() => _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  final MobileScannerController _mobileScannerController = MobileScannerController();
+  late Function(Barcode barcode, MobileScannerArguments? args) _onDetect;
+  bool _isScanning = true;
+
+  @override
+  void initState() {
+    super.initState();
+    _onDetect = (Barcode barcode, MobileScannerArguments? args) {
+      _mobileScannerController.stop();
+      showDialog(
+          context: context,
+          builder: (BuildContext context) {
+            return AlertDialog(
+              title: const Text('Code info'),
+              content: Text(barcode.rawValue?.trim() ?? 'No data found', textAlign: TextAlign.center),
+              actions: [TextButton(onPressed: () => Navigator.pop(context), child: const Text('OK'))],
+            );
+          }).then((value) {
+        _mobileScannerController.start();
+        setState(() {
+          _isScanning = true;
+        });
+      });
+
+      setState(() {
+        _isScanning = false;
+      });
+    };
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: Text(widget.title)),
+      body: Center(
+        child: SizedBox.square(
+          dimension: MediaQuery.of(context).size.width - 48.0,
+          child: Padding(
+            padding: const EdgeInsets.all(2.5), // Required otherwise side edges hides under outside padding
+            child: CustomPaint(
+              foregroundPainter: ScannerBoxBorderPainter(borderColor: _isScanning ? Colors.black : Colors.green),
+              child: Padding(
+                padding: const EdgeInsets.all(2.5), // Required otherwise scanner hides under side edges
+                child: QRCodeScanner(mobileScannerController: _mobileScannerController, allowDuplicates: false, onDetect: _onDetect),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

scan_qr_code/lib/utils/qr_code_scanner.dart

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+import 'package:flutter/material.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+
+class QRCodeScanner extends StatelessWidget {
+  final MobileScannerController mobileScannerController;
+  final bool allowDuplicates;
+  final Function(Barcode barcode, MobileScannerArguments? args) onDetect;
+  const QRCodeScanner({Key? key, required this.mobileScannerController,required this.allowDuplicates, required this.onDetect}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MobileScanner(
+      allowDuplicates: allowDuplicates,
+      controller: mobileScannerController,
+      onDetect: onDetect,
+    );
+  }
+}

scan_qr_code/lib/utils/scanner_box_border_painter.dart

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+import 'package:flutter/material.dart';
+
+class ScannerBoxBorderPainter extends CustomPainter {
+  final Color borderColor;
+
+  ScannerBoxBorderPainter({required this.borderColor});
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    double sh = size.height; // for convenient shortage
+    double sw = size.width; // for convenient shortage
+    double cornerSide = 78.0; // desirable value for corners side
+
+    Paint paint = Paint()
+      ..color = borderColor
+      ..strokeWidth = 5
+      ..style = PaintingStyle.stroke
+      ..strokeCap = StrokeCap.square;
+
+    Path path = Path()
+      ..moveTo(cornerSide, 0)
+      ..lineTo(0, 0)
+      ..lineTo(0, cornerSide)
+      ..moveTo(0, sh - cornerSide)
+      ..lineTo(0, sh)
+      ..lineTo(cornerSide, sh)
+      ..moveTo(sw - cornerSide, sh)
+      ..lineTo(sw, sh)
+      ..lineTo(sw, sh - cornerSide)
+      ..moveTo(sw, cornerSide)
+      ..lineTo(sw, 0)
+      ..lineTo(sw - cornerSide, 0)
+      ..moveTo(cornerSide, 0);
+
+    canvas.drawPath(path, paint);
+  }
+
+  @override
+  bool shouldRepaint(ScannerBoxBorderPainter oldDelegate) => false;
+
+  @override
+  bool shouldRebuildSemantics(ScannerBoxBorderPainter oldDelegate) => false;
+}