地图组件和ECS框架完成

lib/utils/style_dropdown.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import '/utils/map_styles.dart';
+
+class StyleDropdown extends StatefulWidget {
+  const StyleDropdown({required this.onChanged, super.key});
+
+  final void Function(MapStyles style) onChanged;
+
+  static MapStyles get initStyle => MapStyles.openMapTilesLiberty;
+
+  @override
+  State<StyleDropdown> createState() => _StyleDropdownState();
+}
+
+class _StyleDropdownState extends State<StyleDropdown> {
+  late MapStyles _selectedStyle = StyleDropdown.initStyle;
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 8),
+      child: DropdownButton<MapStyles>(
+        value: _selectedStyle,
+        items: MapStyles.values
+            .map((e) => DropdownMenuItem(value: e, child: Text(e.name)))
+            .toList(growable: false),
+        onChanged: (value) {
+          if (value == null) return;
+          setState(() => _selectedStyle = value);
+          widget.onChanged(value);
+        },
+      ),
+    );
+  }
+}