qr page add animated bar

lib/ui/tool_pages/scan_page.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:aku_community_manager/tools/screen_tool.dart';
 import 'package:aku_community_manager/ui/widgets/common/aku_back_button.dart';
 import 'package:bot_toast/bot_toast.dart';
@@ -15,10 +17,24 @@ class _ScanPageState extends State<ScanPage> {
   GlobalKey qrKey = GlobalKey(debugLabel: 'QR');
   QRViewController _qrViewController;
   String tempText;
+  Timer _timer;
+  bool _barMove = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _timer = Timer.periodic(Duration(milliseconds: 1000), (timer) {
+      if (mounted)
+        setState(() {
+          _barMove = !_barMove;
+        });
+    });
+  }
 
   @override
   void dispose() {
     _qrViewController?.dispose();
+    _timer?.cancel();
     super.dispose();
   }
 
@@ -40,7 +56,9 @@ class _ScanPageState extends State<ScanPage> {
             },
           ),
           Center(
-            child: Container(
+            child: Stack(
+              children: [
+                Container(
                   height: 200,
                   width: 200,
                   decoration: BoxDecoration(
@@ -51,6 +69,18 @@ class _ScanPageState extends State<ScanPage> {
                     ),
                   ),
                 ),
+                AnimatedPositioned(
+                  top: _barMove ? 10 : 190,
+                  child: Container(
+                    width: 200,
+                    height: 2,
+                    color: Colors.red,
+                  ),
+                  curve: Curves.easeInOutCubic,
+                  duration: Duration(milliseconds: 300),
+                ),
+              ],
+            ),
           ),
           Positioned(
             left: 10,