Flutter -如何在flutter应用程序上实现新闻计数

import 'package:flutter/material.dart';

void main() => runApp(NewsCounterApp());

class NewsCounterApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'News Counter',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: NewsCounterScreen(),
    );
  }
}

class NewsCounterScreen extends StatefulWidget {
  @override
  _NewsCounterScreenState createState() => _NewsCounterScreenState();
}

class _NewsCounterScreenState extends State<NewsCounterScreen> {
  int _newsCount = 0;

  void _incrementCount() {
    setState(() {
      _newsCount++;
    });
  }

  void _decrementCount() {
    setState(() {
      if (_newsCount > 0) {
        _newsCount--;
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('News Counter'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'News Count:',
              style: TextStyle(fontSize: 24),
            ),
            Text(
              '$_newsCount',
              style: TextStyle(fontSize: 48, fontWeight: FontWeight.bold),
            ),
          ],
        ),
      ),
      floatingActionButton: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          FloatingActionButton(
            onPressed: _decrementCount,
            tooltip: 'Decrement',
            child: Icon(Icons.remove),
          ),
          SizedBox(width: 16),
          FloatingActionButton(
            onPressed: _incrementCount,
            tooltip: 'Increment',
            child: Icon(Icons.add),
          ),
        ],
      ),
    );
  }
}