Android 使用 Flutter 的第一行代碼 -----ListView

api：https://flutterchina.club/get-started/codelab/

 

我接觸Android 正兒八經的第一行代碼就時listView ，沒想到 flutter 的第一個 demo 也是有關 listView 的，哈哈哈

先上代碼

import 'package:flutter/material.dart';
import 'package:english_words/english_words.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
//    return new MaterialApp(
//      title: 'Welcome to Flutter',
//      home: new Scaffold(
//        appBar: new AppBar(
//          title: new Text('Hello Flutter'),
//        ),
//        body: new Center(
////          child: new Text('Hello World'),
//          child: new RandomWords(),
//        ),
//      ),
//    );

    return new MaterialApp(
      title: 'sss',
      theme: new ThemeData(
        primaryColor: Colors.white,
      ),
      home: new RandomWords(),
    );
  }
}

class RandomWords extends StatefulWidget {
  @override
  createState() => new RandomWordsState();
}

class RandomWordsState extends State<RandomWords> {
  final _suggestion = <WordPair>[];
  final _saved = new Set<WordPair>();
  final _biggerFont = const TextStyle(fontSize: 20.0);

  @override
  Widget build(BuildContext context) {
//    final wordPair = new WordPair.random();
    return new Scaffold(
      appBar: new AppBar(
        title: new Text("listView_test____"),
        actions: <Widget>[
          new IconButton(icon: new Icon(Icons.list), onPressed: _pushSaved),
        ],
      ),
      body: _buildSuggestions(),
    );
//    return new Text(wordPair.asPascalCase);
  }

  void _pushSaved() {
    Navigator.of(context).push(new MaterialPageRoute(builder: (context) {
      final tiles = _saved.map((pair) {
        return new ListTile(
          title: new Text(
            pair.asPascalCase,
            style: _biggerFont,
          ),
        );
      });
      final divided =
          ListTile.divideTiles(context: context, tiles: tiles).toList();

      return new Scaffold( appBar: new AppBar(
        title: new Text('saved Suggestions'),
      ),
      body:  new ListView(children: divided,),
      );
    }));
  }

  Widget _buildSuggestions() {
    return new ListView.builder(
        padding: const EdgeInsets.all(1.0),
        // 對於每個建議的單詞對都會調用一次itemBuilder，然後將單詞對添加到ListTile行中
        // 在偶數行，該函數會爲單詞對添加一個ListTile row.
        // 在奇數行，該函數會添加一個分割線widget，來分隔相鄰的詞對。
        // 注意，在小屏幕上，分割線看起來可能比較吃力。
        itemBuilder: (context, i) {
          if (i.isOdd) return new Divider();
          final index = i ~/ 2;
          if (index >= _suggestion.length) {
            _suggestion.addAll(generateWordPairs().take(10));
          }
          return _buildRow(_suggestion[index]);
        });
  }

  Widget _buildRow(WordPair pair) {
    final alreadySaved = _saved.contains(pair);
    return new ListTile(
      title: new Text(
        pair.asPascalCase,
        style: _biggerFont,
      ),
      trailing: new Icon(
        alreadySaved ? Icons.favorite : Icons.favorite_border,
        color: alreadySaved ? Colors.red : null,
      ),
      onTap: () {
        setState(() {
          if (alreadySaved) {
            _saved.remove(pair);
          } else {
            _saved.add(pair);
          }
        });
      },
    );
  }
}