完成录制功能

lib/features/recording/widgets/camera_preview_widget.dart

@@ -0,0 +1,25 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+class CameraPreviewWidget extends StatelessWidget {
+  const CameraPreviewWidget({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    if (!Platform.isAndroid) {
+      return const ColoredBox(
+        color: Colors.black,
+        child: Center(child: Text('仅 Android 支持相机预览')),
+      );
+    }
+
+    return AndroidView(
+      viewType: 'recording-camera-preview',
+      layoutDirection: TextDirection.ltr,
+      creationParams: const <String, dynamic>{},
+      creationParamsCodec: const StandardMessageCodec(),
+    );
+  }
+}

lib/features/recording/widgets/recording_touch_lock_overlay.dart

@@ -0,0 +1,100 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+class RecordingTouchLockOverlay extends StatefulWidget {
+  const RecordingTouchLockOverlay({
+    super.key,
+    required this.enabled,
+    required this.onUnlocked,
+    this.unlockHoldDuration = const Duration(seconds: 2),
+  });
+
+  final bool enabled;
+  final VoidCallback onUnlocked;
+  final Duration unlockHoldDuration;
+
+  @override
+  State<RecordingTouchLockOverlay> createState() =>
+      _RecordingTouchLockOverlayState();
+}
+
+class _RecordingTouchLockOverlayState extends State<RecordingTouchLockOverlay> {
+  Timer? _holdTimer;
+  bool _isHolding = false;
+
+  @override
+  void didUpdateWidget(RecordingTouchLockOverlay oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (!widget.enabled) {
+      _cancelHold();
+    }
+  }
+
+  @override
+  void dispose() {
+    _cancelHold();
+    super.dispose();
+  }
+
+  void _cancelHold() {
+    _holdTimer?.cancel();
+    _holdTimer = null;
+    _isHolding = false;
+  }
+
+  void _startHold() {
+    if (!widget.enabled) return;
+    setState(() => _isHolding = true);
+    _holdTimer?.cancel();
+    _holdTimer = Timer(widget.unlockHoldDuration, () {
+      if (!mounted) return;
+      _cancelHold();
+      widget.onUnlocked();
+      setState(() {});
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (!widget.enabled) {
+      return const SizedBox.shrink();
+    }
+
+    return Positioned.fill(
+      child: Listener(
+        behavior: HitTestBehavior.opaque,
+        onPointerDown: (_) => _startHold(),
+        onPointerUp: (_) => _cancelHold(),
+        onPointerCancel: (_) => _cancelHold(),
+        child: ColoredBox(
+          color: Colors.black.withValues(alpha: 0.01),
+          child: Align(
+            alignment: Alignment.topCenter,
+            child: Padding(
+              padding: const EdgeInsets.only(top: 48),
+              child: DecoratedBox(
+                decoration: BoxDecoration(
+                  color: Colors.black54,
+                  borderRadius: BorderRadius.circular(24),
+                ),
+                child: Padding(
+                  padding: const EdgeInsets.symmetric(
+                    horizontal: 16,
+                    vertical: 8,
+                  ),
+                  child: Text(
+                    _isHolding
+                        ? '保持按住 ${widget.unlockHoldDuration.inSeconds}s 解锁…'
+                        : '防误触已开启，按住 ${widget.unlockHoldDuration.inSeconds}s 解锁',
+                    style: const TextStyle(color: Colors.white, fontSize: 13),
+                  ),
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}