v

lib/05/04/main.dart

@@ -0,0 +1,77 @@
+import 'package:flutter/material.dart';
+
+void main() {
+  runApp(const OverlayPage());
+}
+
+class OverlayPage extends StatefulWidget {
+  const OverlayPage({super.key});
+
+  @override
+  State<OverlayPage> createState() => _OverlayPageState();
+}
+
+class _OverlayPageState extends State<OverlayPage> {
+  double _left = 0;
+  double _top = 0;
+
+  @override
+  Widget build(BuildContext context) {
+    final OverlayEntry home =
+        OverlayEntry(builder: (BuildContext context) => const HomePage());
+
+    final OverlayEntry circle = OverlayEntry(
+        builder: (BuildContext context) => Positioned(
+              top: 50,
+              left: 50,
+              child: GestureDetector(
+                onPanUpdate: _updatePosition,
+                child: const Circle(),
+              ),
+            ));
+
+    return Directionality(
+      textDirection: TextDirection.ltr,
+      child: Overlay(
+        initialEntries: [home, circle],
+      ),
+    );
+  }
+
+  void _updatePosition(DragUpdateDetails details) {
+    setState(() {
+      _top += details.delta.dy;
+      _left += details.delta.dx;
+    });
+  }
+}
+
+class HomePage extends StatelessWidget {
+  const HomePage({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return const ColoredBox(
+      color: Colors.white,
+      child: Align(
+        child: FlutterLogo(
+          size: 60,
+        ),
+      ),
+    );
+  }
+}
+
+class Circle extends StatelessWidget {
+  const Circle({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: 20,
+      height: 20,
+      decoration:
+          const BoxDecoration(color: Colors.redAccent, shape: BoxShape.circle),
+    );
+  }
+}