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java
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView = findViewById(R.id.textView);
textView.setText("Hello, World!");
}
}
Kotlin 示例 (也是Android Studio):
kotlin
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
textView.text = "Hello, World!"
}
}
2. iOS (Swift/Objective-C)
Swift 示例 (使用Xcode开发):
swift
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let label = UILabel()
label.text = "Hello, World!"
label.frame = CGRect(x: 0, y: 0, width: 200, height: 21)
label.center = view.center
view.addSubview(label)
}
}
Objective-C 示例 (也是Xcode):
objc
#import “ViewController.h”
@interface ViewController ()
@end
@implementation ViewController
@end
3. Flutter (Dart)
Dart 示例 (用于Flutter App,使用Android Studio或VS Code):
dart
import ‘package:flutter/material.dart’;
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: ‘Welcome to Flutter’,
home: Scaffold(
appBar: AppBar(
title: Text(‘Welcome to Flutter’),
),
body: Center(
child: Text(‘Hello, World!’),
),
),
);
}
}
4. React Native (JavaScript/TypeScript)
JavaScript 示例 (使用Expo或React Native CLI,开发环境可以是VS Code、WebStorm等):
jsx
import React from ‘react’;
import { View, Text, StyleSheet } from ‘react-native’;
export default function App() {
return (
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: ‘center’,
alignItems: ‘center’,
},
});
TypeScript 示例 (与JavaScript类似,但增加了类型检查):
TypeScript在React Native中的使用方式与JavaScript类似,但文件扩展名为.tsx,并允许类型注解。
注意:以上示例仅展示了如何在一个简单的屏幕上显示"Hello, World!"文本。要构建一个完整的App,你需要进一步学习如何设计用户界面、处理用户输入、与后端服务通信等。由于生成一个完整的App代码涉及多个方面(如用户界面、业务逻辑、数据存储等),并且每种语言都有其特定的开发环境和框架,我将为你提供几种流行编程语言的简要示例或框架说明,而不是完整的App代码。
java
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView = findViewById(R.id.textView);
textView.setText("Hello, World!");
}
}
Kotlin 示例 (也是Android Studio):
kotlin
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
textView.text = "Hello, World!"
}
}
2. iOS (Swift/Objective-C)
Swift 示例 (使用Xcode开发):
swift
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let label = UILabel()
label.text = "Hello, World!"
label.frame = CGRect(x: 0, y: 0, width: 200, height: 21)
label.center = view.center
view.addSubview(label)
}
}
Objective-C 示例 (也是Xcode):
objc
#import “ViewController.h”
@interface ViewController ()
@end
@implementation ViewController
@end
3. Flutter (Dart)
Dart 示例 (用于Flutter App,使用Android Studio或VS Code):
dart
import ‘package:flutter/material.dart’;
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: ‘Welcome to Flutter’,
home: Scaffold(
appBar: AppBar(
title: Text(‘Welcome to Flutter’),
),
body: Center(
child: Text(‘Hello, World!’),
),
),
);
}
}
4. React Native (JavaScript/TypeScript)
JavaScript 示例 (使用Expo或React Native CLI,开发环境可以是VS Code、WebStorm等):
jsx
import React from ‘react’;
import { View, Text, StyleSheet } from ‘react-native’;
export default function App() {
return (
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: ‘center’,
alignItems: ‘center’,
},
});
TypeScript 示例 (与JavaScript类似,但增加了类型检查):
TypeScript在React Native中的使用方式与JavaScript类似,但文件扩展名为.tsx,并允许类型注解。
注意:以上示例仅展示了如何在一个简单的屏幕上显示"Hello, World!"文本。要构建一个完整的App,你需要进一步学习如何设计用户界面、处理用户输入、与后端服务通信等。
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