optimize channel test

lib/battery.dart

@@ -52,24 +52,31 @@ class _PlatformChannelState extends State<PlatformChannel> {
   @override
   Widget build(BuildContext context) {
     return Material(
-      child: Column(
-        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-        children: <Widget>[
-          Column(
-            mainAxisAlignment: MainAxisAlignment.center,
+      child: Scaffold(
+        appBar: AppBar(
+          title: Text('Channel test'),
+        ),
+        body: Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
             children: <Widget>[
-              Text(_batteryLevel, key: const Key('Battery level label')),
-              Padding(
-                padding: const EdgeInsets.all(16.0),
-                child: RaisedButton(
-                  child: const Text('Refresh'),
-                  onPressed: _getBatteryLevel,
-                ),
+              Column(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: <Widget>[
+                  Text(_batteryLevel, key: const Key('Battery level label')),
+                  Padding(
+                    padding: const EdgeInsets.all(16.0),
+                    child: RaisedButton(
+                      child: const Text('Refresh'),
+                      onPressed: _getBatteryLevel,
+                    ),
+                  ),
+                ],
               ),
+              Text(_chargingStatus),
             ],
           ),
-          Text(_chargingStatus),
-        ],
+        ),
       ),
     );
   }

lib/main.dart

@@ -107,6 +107,7 @@ class _MyHomePageState extends State<MyHomePage> {
             ),
             FlatButton(
               child: Text('channel test'),
+              color: Colors.green,
               onPressed: (){Navigator.pushNamed(context, "/channeltest");},
             )
           ],