Update gf_search_bar.dart

Author: shubhams-geekyants

lib/components/search_bar/gf_search_bar.dart

@@ -15,7 +15,7 @@ class GFSearchBar<T> extends StatefulWidget {
     @required this.overlaySearchListItemBuilder,
     @required this.searchQueryBuilder,
     Key key,
-    this.controller = const TextEditingController(),
+    this.controller,
     this.onItemSelected,
     this.hideSearchBoxWhenItemSelected = false,
     this.overlaySearchListHeight,
@@ -68,7 +68,7 @@ class MySingleChoiceSearchState<T> extends State<GFSearchBar<T>> {
   double overlaySearchListHeight;
   final LayerLink _layerLink = LayerLink();
   final double textBoxHeight = 48;
-  final TextEditingController textController = TextEditingController();
+  TextEditingController textController = TextEditingController();
   bool isSearchBoxSelected = false;
 
   @override
@@ -79,14 +79,15 @@ class MySingleChoiceSearchState<T> extends State<GFSearchBar<T>> {
 
   void init() {
     _searchList = <T>[];
+    textController = widget.controller ?? textController;
     notifier = ValueNotifier(null);
     _focusNode = FocusNode();
     isFocused = false;
     _list = List<T>.from(widget.searchList);
     _searchList.addAll(_list);
     _focusNode.addListener(() {
       if (!_focusNode.hasFocus) {
-        widget.controller.clear();
+        textController.clear();
         if (overlaySearchList != null) {
           overlaySearchList.remove();
         }
@@ -102,8 +103,8 @@ class MySingleChoiceSearchState<T> extends State<GFSearchBar<T>> {
         }
       }
     });
-    widget.controller.addListener(() {
-      final text = widget.controller.text;
+    textController.addListener(() {
+      final text = textController.text;
       if (text.trim().isNotEmpty) {
         _searchList.clear();
         final filterList = widget.searchQueryBuilder(text, widget.searchList);
@@ -146,7 +147,7 @@ class MySingleChoiceSearchState<T> extends State<GFSearchBar<T>> {
       padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 16),
       margin: const EdgeInsets.only(bottom: 12),
       child: TextField(
-        controller: widget.controller,
+        controller: textController,
         focusNode: _focusNode,
         style: TextStyle(fontSize: 16, color: Colors.grey[600]),
         decoration: widget.searchBoxInputDecoration == null