build: 控制端功能移植到flutter版本

webrtc_controller_flutter/lib/widgets/remote_touch_view.dart

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+import 'dart:math';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+/// 远端触摸控制层（对应 Android 端 RemoteTouchView）。
+///
+/// 捕获指针（触摸/鼠标）事件，将其转换为相对于控件区域的百分比坐标
+/// （0.0 ~ 1.0），以便在不同分辨率的设备间换算。
+///
+/// - 短时间内位移很小的抬起 -> 单击（TOUCH）
+/// - 否则 -> 滑动（SWIPE）
+/// 同时捕获物理按键事件（KEY），用于外接键盘 / 遥控器场景。
+///
+/// 该控件完全基于 Flutter 框架实现，无需任何原生代码，可运行于
+/// Android、iOS 等平台。
+class RemoteTouchView extends StatefulWidget {
+  final void Function(double x, double y) onTouch;
+  final void Function(
+    double x1,
+    double y1,
+    double x2,
+    double y2,
+    int durationMs,
+  ) onSwipe;
+  final void Function(int keyCode, int action) onKey;
+
+  const RemoteTouchView({
+    super.key,
+    required this.onTouch,
+    required this.onSwipe,
+    required this.onKey,
+  });
+
+  @override
+  State<RemoteTouchView> createState() => _RemoteTouchViewState();
+}
+
+class _RemoteTouchViewState extends State<RemoteTouchView> {
+  Offset? _startPosition;
+  DateTime? _startTime;
+
+  double _toRelativeX(Offset local, Size size) =>
+      (local.dx / size.width).clamp(0.0, 1.0);
+
+  double _toRelativeY(Offset local, Size size) =>
+      (local.dy / size.height).clamp(0.0, 1.0);
+
+  @override
+  Widget build(BuildContext context) {
+    return Focus(
+      autofocus: true,
+      // 捕获物理按键（外接键盘 / 遥控器等）。
+      onKeyEvent: (node, event) {
+        if (event is KeyDownEvent) {
+          widget.onKey(event.logicalKey.keyId, 0);
+          return KeyEventResult.handled;
+        } else if (event is KeyUpEvent) {
+          widget.onKey(event.logicalKey.keyId, 1);
+          return KeyEventResult.handled;
+        }
+        return KeyEventResult.ignored;
+      },
+      child: Listener(
+        behavior: HitTestBehavior.opaque,
+        onPointerDown: (event) {
+          _startPosition = event.localPosition;
+          _startTime = DateTime.now();
+        },
+        onPointerUp: (event) {
+          final size = context.size;
+          if (_startPosition == null || size == null || _startTime == null) {
+            return;
+          }
+          final startX = _toRelativeX(_startPosition!, size);
+          final startY = _toRelativeY(_startPosition!, size);
+          final endX = _toRelativeX(event.localPosition, size);
+          final endY = _toRelativeY(event.localPosition, size);
+          final duration = DateTime.now().difference(_startTime!).inMilliseconds;
+
+          final dx = (endX - startX).abs();
+          final dy = (endY - startY).abs();
+
+          if (duration < 200 && dx < 0.02 && dy < 0.02) {
+            widget.onTouch(startX, startY);
+          } else {
+            widget.onSwipe(startX, startY, endX, endY, max(duration, 1));
+          }
+          _startPosition = null;
+          _startTime = null;
+        },
+        child: const ColoredBox(
+          color: Colors.transparent,
+          child: SizedBox.expand(),
+        ),
+      ),
+    );
+  }
+}