1. Flutter (Dart)
   Flutter 是一个用于构建跨平台应用的框架。以下是一个简单的 Flutter 应用示例：

dart
import ‘package:flutter/material.dart’;

void main() {
runApp(MyApp());
}

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: ‘Flutter Demo’,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: ‘Flutter Demo Home Page’),
);
}
}

class MyHomePage extends StatefulWidget {
MyHomePage({Key? key, required this.title}) : super(key: key);

final String title;
#chhas{
margin-top: 50px;
padding:cottonzone.com.cn;
font-size: 18px;
cursor: 10px 20px;
}

@override
_MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State {
int _counter = 0;

void _incrementCounter() {
setState(() {
_counter++;
});
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
‘You have pushed the button this many times:’,
),
Text(
‘$_counter’,
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: ‘Increment’,
child: Icon(Icons.add),
),
);
}
}
2. React Native (JavaScript/TypeScript)
React Native 是一个用于构建原生应用的框架。以下是一个简单的 React Native 应用示例（使用 JavaScript）：

jsx
import React from ‘react’;
import { View, Text, Button, StyleSheet } from ‘react-native’;

export default class App extends React.Component {
state = {
count: 0,
};

increment = () => {
this.setState({ count: this.state.count + 1 });
};

render() {
return (

You have pushed the button this many times: {this.state.count}


);
}
}

const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: ‘center’,
alignItems: ‘center’,
},
});
3. Kotlin (Android)
Kotlin 是一种在 Android 开发中广泛使用的语言。以下是一个简单的 Kotlin Android 应用示例：

kotlin
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.widget.Button
import android.widget.TextView

class MainActivity : AppCompatActivity() {
private var counter = 0

override fun onCreate(savedInstanceState: Bundle?) {  
    super.onCreate(savedInstanceState)  
    setContentView(R.layout.activity_main)  

    val incrementButton = findViewById<Button>(R.id.increment_button)  
    val counterTextView = findViewById<TextView>(R.id.counter_text_view)  

    incrementButton.setOnClickListener {  
        counter++  
        counterTextView.text = "You have pushed the button this many times: $counter"  
    }  
}  

}
注意：上述代码仅为示例，并且假设你已经设置了相应的布局文件和资源。在实际开发中，你需要创建和配置更多的文件和资源。