diff --git a/example/README.md b/example/README.md
index a135626..70f37e6 100644
--- a/example/README.md
+++ b/example/README.md
@@ -1,16 +1,7 @@
 # example
 
-A new Flutter project.
+生成随机字符，包括汉字，八卦符或emoji
 
-## Getting Started
+## description
+练习用
 
-This project is a starting point for a Flutter application.
-
-A few resources to get you started if this is your first Flutter project:
-
-- [Lab: Write your first Flutter app](https://flutter.dev/docs/get-started/codelab)
-- [Cookbook: Useful Flutter samples](https://flutter.dev/docs/cookbook)
-
-For help getting started with Flutter, view our
-[online documentation](https://flutter.dev/docs), which offers tutorials,
-samples, guidance on mobile development, and a full API reference.
diff --git a/example/lib/main.dart b/example/lib/main.dart
index 4713506..178c6b7 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -6,85 +6,36 @@ void main() {
 }
 
 class MyApp extends StatelessWidget {
-  // This widget is the root of your application.
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
-      title: 'Flutter Demo',
+      title: 'random character',
       theme: ThemeData(
-        // This is the theme of your application.
-        //
-        // Try running your application with "flutter run". You'll see the
-        // application has a blue toolbar. Then, without quitting the app, try
-        // changing the primarySwatch below to Colors.green and then invoke
-        // "hot reload" (press "r" in the console where you ran "flutter run",
-        // or simply save your changes to "hot reload" in a Flutter IDE).
-        // Notice that the counter didn't reset back to zero; the application
-        // is not restarted.
+        
         primarySwatch: Colors.blue,
-        // This makes the visual density adapt to the platform that you run
-        // the app on. For desktop platforms, the controls will be smaller and
-        // closer together (more dense) than on mobile platforms.
         visualDensity: VisualDensity.adaptivePlatformDensity,
       ),
-      home: MyHomePage(title: 'Flutter Demo Home Page'),
+      home: MyHomePage(title: 'random character'),
     );
   }
 }
 
 class MyHomePage extends StatefulWidget {
   MyHomePage({Key? key, required this.title}) : super(key: key);
-
-  // This widget is the home page of your application. It is stateful, meaning
-  // that it has a State object (defined below) that contains fields that affect
-  // how it looks.
-
-  // This class is the configuration for the state. It holds the values (in this
-  // case the title) provided by the parent (in this case the App widget) and
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
-
   final String title;
-
   @override
   _MyHomePageState createState() => _MyHomePageState();
 }
-
 class _MyHomePageState extends State<MyHomePage> {
   String _char = '';
-
   @override
   Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
     return Scaffold(
       appBar: AppBar(
-        // Here we take the value from the MyHomePage object that was created by
-        // the App.build method, and use it to set our appbar title.
         title: Text(widget.title),
       ),
       body: Center(
-        // Center is a layout widget. It takes a single child and positions it
-        // in the middle of the parent.
         child: Column(
-          // Column is also a layout widget. It takes a list of children and
-          // arranges them vertically. By default, it sizes itself to fit its
-          // children horizontally, and tries to be as tall as its parent.
-          //
-          // Invoke "debug painting" (press "p" in the console, choose the
-          // "Toggle Debug Paint" action from the Flutter Inspector in Android
-          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
-          // to see the wireframe for each widget.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             Text(