scanner

lib/src/scanner.dart

@@ -0,0 +1,116 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/gestures.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+
+/// Barcode formats the platform decoder will look for. Today only QR is
+/// supported; the enum exists for forward-compatibility with the native
+/// channel arguments.
+enum BarcodeFormat { qr }
+
+/// Static helpers exposed by the platform-side scanner plugin.
+class UxScannerPermission {
+  UxScannerPermission._();
+
+  static const _channel = MethodChannel('ux/scanner');
+
+  /// Requests camera permission. Returns `true` once the OS has reported
+  /// authorized; `false` if the user denied or the platform is
+  /// unsupported. Safe to call multiple times — already-granted returns
+  /// `true` immediately.
+  static Future<bool> requestCamera() async {
+    if (defaultTargetPlatform != TargetPlatform.iOS &&
+        defaultTargetPlatform != TargetPlatform.android) {
+      return false;
+    }
+    final granted = await _channel.invokeMethod<bool>('requestPermission');
+    return granted ?? false;
+  }
+}
+
+/// Camera-preview widget that emits decoded barcode payloads.
+///
+/// Backed by AVFoundation on iOS (built-in QR support, no extra dep) and
+/// CameraX + ZXing on Android. The widget mounts a platform-view —
+/// `UiKitView` on iOS, `AndroidView` on Android — and listens to a
+/// per-process event channel for decoded strings.
+///
+/// Camera permission must be granted by the host app before mounting.
+/// On platforms other than iOS / Android the widget renders an empty
+/// box.
+class UxScanner extends StatefulWidget {
+  const UxScanner({
+    super.key,
+    required this.onCode,
+    this.formats = const [BarcodeFormat.qr],
+  });
+
+  final ValueChanged<String> onCode;
+  final List<BarcodeFormat> formats;
+
+  @override
+  State<UxScanner> createState() => _UxScannerState();
+}
+
+class _UxScannerState extends State<UxScanner> {
+  static const _events = EventChannel('ux/scanner/events');
+  StreamSubscription<dynamic>? _sub;
+
+  @override
+  void initState() {
+    super.initState();
+    _sub = _events.receiveBroadcastStream().listen((event) {
+      final code = event as String?;
+      if (code == null || !mounted) return;
+      widget.onCode(code);
+    });
+  }
+
+  @override
+  void dispose() {
+    _sub?.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final creationParams = <String, Object?>{
+      'formats': widget.formats.map((e) => e.name).toList(),
+    };
+    if (defaultTargetPlatform == TargetPlatform.iOS) {
+      return UiKitView(
+        viewType: 'ux/scanner',
+        creationParams: creationParams,
+        creationParamsCodec: const StandardMessageCodec(),
+      );
+    }
+    if (defaultTargetPlatform == TargetPlatform.android) {
+      return PlatformViewLink(
+        viewType: 'ux/scanner',
+        surfaceFactory: (context, controller) {
+          return AndroidViewSurface(
+            controller: controller as AndroidViewController,
+            gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{},
+            hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+          );
+        },
+        onCreatePlatformView: (params) {
+          return PlatformViewsService.initSurfaceAndroidView(
+            id: params.id,
+            viewType: 'ux/scanner',
+            layoutDirection: TextDirection.ltr,
+            creationParams: creationParams,
+            creationParamsCodec: const StandardMessageCodec(),
+            onFocus: () => params.onFocusChanged(true),
+          )
+            ..addOnPlatformViewCreatedListener(params.onPlatformViewCreated)
+            ..create();
+        },
+      );
+    }
+    return const SizedBox.shrink();
+  }
+}