flutter例子07

import 'package:flutter/material.dart';

void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyScaffld(),
    );
  }
}

class MyScaffld extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('AppBar示例'),
        leading: FlutterLogo(colors: Colors.lightGreen),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.share),
            onPressed: () {
              print('添加按钮');
            },
          ),
        ],
      ),
    );
  }
}

#例子02

import 'package:flutter/material.dart';

void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: AppBar(
          title: Text('ListView示例'),
        ),
        body: ListView(
          children: <Widget>[
            ListTile(
              leading: Icon(Icons.access_time),
              title: Text('第1行'),
            ),
            ListTile(
              leading: Icon(Icons.access_time),
              title: Text('第2行'),
            ),
          ],
        ),
      ),
    );
  }
}

#例子03

import 'package:flutter/material.dart';

void main() => runApp(MyApp(
      items: new List<String>.generate(300, (i) => "第$i行"), //1
    ));

class MyApp extends StatelessWidget {
  final List<String> items;

  MyApp({@required this.items});
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: AppBar(
          title: Text('ListView示例'),
        ),
        body: ListView.builder( //2
          itemCount: items.length,
          itemBuilder: (context, index) {
            return ListTile(
              leading: Icon(Icons.access_time),
              title: Text('${items[index]}'),
            );
          },
        ),
      ),
    );
  }
}

#例子04

import 'package:flutter/material.dart';

void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: AppBar(
          title: new Text('GridView示例'),
        ),
        body: GridView.count(
          crossAxisCount: 3, //1
          children: <Widget>[
            ListTile(
              title: Text('item1'),
            ),
            ListTile(
              title: Text('item2'),
            ),
            ListTile(
              title: Text('item3'),
            ),
            ListTile(
              title: Text('item4'),
            ),
            ListTile(
              title: Text('item5'),
            ),
            ListTile(
              title: Text('item6'),
            ),
            ListTile(
              title: Text('item7'),
            ),
            ListTile(
              title: Text('item8'),
            ),
            ListTile(
              title: Text('item9'),
            ),
          ],
        ),
      ),
    );
  }
}

#例子05

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: AppBar(
          title: Text('PageView示例'),
        ),
        body: PageView(
          onPageChanged: (index) {//1
            print('当前为第 $index 页');
          },
          children: <Widget>[
            ListTile(
              title: Text('第0页'),
            ),
            ListTile(
              title: Text('第1页'),
            ),
            ListTile(
              title: Text('第2页'),
            ),
          ],
        ),
      ),
    );
  }
}

#例子06

import 'package:flutter/material.dart';

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

class GestureDetectorWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter",
      home: Scaffold(
        appBar: AppBar(
          title: Text("GestureDetector示例"),
        ),
        body: Center(
          child: GestureDetector(
            child: Text('手势识别'),
            onTap: () {
              print('点击');
            },
            onDoubleTap: () {
              print('双击');
            },
            onLongPress: () {
              print('长按');
            },
            onHorizontalDragStart: (DragStartDetails details) {
              print('水平拖动');
            },
          ),
        ),
      ),
    );
  }
}

#例子07

import 'package:flutter/material.dart';
import 'dart:convert' show json;
void main() => runApp(AssetsWidget());

class AssetsWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter",
      home: Scaffold(
        appBar: AppBar(
          title: Text("加载文本示例"),
        ),
        body:JsonWidget(),
      ),
    );
  }
}
class JsonWidget extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _JsonWidgetState();
  }
}
class _JsonWidgetState extends State<JsonWidget> {
  @override
  Widget build(BuildContext context) {
    return FutureBuilder(//1
      future: DefaultAssetBundle.of(context).loadString("assets/swordsmen.json"),//2
      builder: (context, snapshot) {
        if (!snapshot.hasData) {//3
          return  Center(
            child: CircularProgressIndicator(),
          );
        }else{
          List<dynamic> data = json.decode(snapshot.data.toString());//4
          return ListView.builder(
            itemCount: data.length,
            itemBuilder: (BuildContext context, int index) {
              return Card(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: <Widget>[
                    Text("名字: ${data[index]["name"]}"),
                    Text("绝学: ${data[index]["gongfu"]}"),
                  ],
                ),
              );
            },
          );
        }
      },
    );
  }
}

#例子08