created clearing dropdown menus

lib/widgets/clearing_dropdown_menu.dart

@@ -0,0 +1,81 @@
+import 'package:flutter/material.dart';
+
+class ClearingDropdownMenu<T> extends StatefulWidget {
+  final List<DropdownMenuEntry<T>> entries;
+  final T? initialValue;
+  final void Function(T? item)? onSelected;
+  final String? label;
+
+  const ClearingDropdownMenu({
+    super.key,
+    required this.entries,
+    this.initialValue,
+    this.onSelected,
+    this.label,
+  });
+
+  @override
+  State<ClearingDropdownMenu<T>> createState() =>
+      _ClearingDropdownMenuState<T>();
+}
+
+class _ClearingDropdownMenuState<T> extends State<ClearingDropdownMenu<T>> {
+  late final TextEditingController _controller;
+  final FocusNode _focusNode = FocusNode();
+  T? _selectedValue;
+
+  @override
+  void initState() {
+    super.initState();
+    _selectedValue = widget.initialValue;
+    _controller = TextEditingController(
+        text: _selectedValue != null
+            ? widget.entries
+                .firstWhere((entry) => entry.value == _selectedValue)
+                .label
+            : '');
+
+    _focusNode.addListener(_onFocusChange);
+  }
+
+  void _onFocusChange() {
+    if (!_focusNode.hasFocus) {
+      // Check if the current text matches any entry
+      final validEntry = widget.entries.any((entry) =>
+          entry.label.toLowerCase() == _controller.text.toLowerCase());
+
+      if (!validEntry) {
+        // Clear the text and selection
+        _controller.clear();
+        setState(() {
+          _selectedValue = null;
+        });
+        widget.onSelected?.call(null);
+      }
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return DropdownMenu<T>(
+      controller: _controller,
+      focusNode: _focusNode,
+      initialSelection: widget.initialValue,
+      onSelected: (T? value) {
+        setState(() {
+          _selectedValue = value;
+        });
+        widget.onSelected?.call(value);
+      },
+      dropdownMenuEntries: widget.entries,
+      label: widget.label != null ? Text(widget.label!) : null,
+    );
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    _focusNode.dispose();
+    super.dispose();
+  }
+}