1、修改SearchAppBar

lib/widget/search_app_bar.dart

@@ -49,9 +49,7 @@ class _SearchAppBarState extends State<SearchAppBar> {
         titleSpacing: 0.0,
         primary: widget.primary,
         leading: widget.leading,
-        title: Container(
-          color: Colors.blue,
-          child: Row(
+        title: Row(
           children: <Widget>[
             Expanded(
               child: Container(
@@ -109,7 +107,6 @@ class _SearchAppBarState extends State<SearchAppBar> {
           ],
         ),
       ),
-      ),
     );
   }