1、SearchAppBar：增加属性 textEditingController

lib/widget/search_app_bar.dart

@@ -22,6 +22,7 @@ class SearchAppBar extends StatefulWidget implements PreferredSizeWidget {
   final Widget? leftWidget;
   final EdgeInsetsGeometry? margin;
   final bool automaticallyImplyLeading;
+  final TextEditingController? textEditingController;
 
   const SearchAppBar({
     Key? key,
@@ -43,6 +44,7 @@ class SearchAppBar extends StatefulWidget implements PreferredSizeWidget {
     this.leftWidget,
     this.margin,
     this.automaticallyImplyLeading = true,
+    this.textEditingController,
   }) : super(key: key);
 
   @override
@@ -53,7 +55,7 @@ class SearchAppBar extends StatefulWidget implements PreferredSizeWidget {
 }
 
 class _SearchAppBarState extends State<SearchAppBar> {
-  final _searchInfoController = TextEditingController();
+  late TextEditingController _searchInfoController;
   final _searchFocusNode = FocusNode();
 
   @override
@@ -63,6 +65,7 @@ class _SearchAppBarState extends State<SearchAppBar> {
         widget.onFocusListener!(_searchFocusNode.hasFocus);
       }
     });
+    _searchInfoController = widget.textEditingController ?? TextEditingController();
     super.initState();
   }