New Example - QR Code Scanner (#122)

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

scan_qr_code/lib/utils/qr_code_scanner.dart

@@ -0,0 +1,18 @@
+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

@@ -0,0 +1,43 @@
+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;
+}