basic structure with material 3

lib/testUI.dart

@@ -0,0 +1,29 @@
+import 'package:flutter/material.dart';
+
+class TestUI extends StatefulWidget {
+  const TestUI({super.key});
+
+  @override
+  State<TestUI> createState() => _TestUIState();
+}
+
+class _TestUIState extends State<TestUI> {
+  int _test = 0;
+
+  void _onPressed() {
+    setState(() {
+      _test = 1;
+    });
+  }
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: Column(children: [
+          FloatingActionButton(onPressed: _onPressed),
+          Text('$_test'),
+        ],),
+      ),
+    );
+  }
+}