flutter组件

import ‘package:flutter/material.dart‘;
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Text(
        ‘你好吗？‘,
        textDirection: TextDirection.ltr,
        textAlign: TextAlign.center,
        overflow: TextOverflow.ellipsis,
        style: TextStyle(fontWeight: FontWeight.normal),
      ),
    );
  }
}

1. 读取本地图片资源
 
调用方式是Image.asset
 
注意 需要配置项目根目录下的 pubspec.yaml  文件，文件中配置默认如下，默认是有asserts：
（1）. 但是默认是关闭的，需要打开 
（2）.根目录创建images目录，存储图片
（3）.注意 格式一定要正确，否则也会报错
 
/**
flutter:
  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true
  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/share_image.png
  #  - images/a_dot_burr.jpeg
**/
 
 
import ‘package:flutter/material.dart‘;
void main(){
  runApp(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(‘Welcome to Flutter‘),
        ),
        body: Image.asset("images/share_image.png"),
      ),
    );
  }
}
 
2. 读取网络图片资源
 
注意，网络图片的 调用方式为 Image.network()
 
import ‘package:flutter/material.dart‘;
void main(){
  runApp(MyAppLocImage());
}
 
//网络图片加载
class MyAppLocImage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: ‘Welcome to Flutter‘,//标题名称
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text(‘Welcome to Flutter‘),//标题名称
        ),
        body: Image.network("https://www.baidu.com/img/bd_logo1.png"),//图片加载地图
      ),
    );
  }
}
 

/*****************************动态组件****************************/
 
class TextPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => MyState();
}
 
class MyState extends State<TextPage> {
  var _count = 0;
 
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar: new AppBar(
          title: new Text("Hello StatefulWidget"),
        ),
        body: new Stack(
          children: <Widget>[
            new Align(
              child: new Text(
                "count值:$_count",
                style: new TextStyle(fontSize: 18.0),
                textAlign: TextAlign.center,
              ),
            ),
            new Align(
              alignment: new FractionalOffset(0.5, 0.0),
              child: new MaterialButton(
                color: Colors.blueAccent,
                textColor: Colors.white,
                onPressed: () {
                  //重新渲染当前的状态
                  setState(() {
                    _count++;
                  });
                },
                child: new Text(‘点我加下方文字自动加1‘),
              ),
            ),
          ],
        ));
  }
}

import ‘package:flutter/material.dart‘;
void main(){
  runApp(MaterialApp(
    title:‘‘,
    home: SecondScreen(),
  ));
}
 
/**************************标题设置****************************/
 
class SecondScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      //标题设置，包括：标题
      appBar: AppBar(
        title: new Text(‘首页‘),
        leading: new Icon(Icons.arrow_back),
        backgroundColor: Colors.blue,
        centerTitle: true,
      ),
      body: Center(
        child: RaisedButton(
          child: Text("该页面有标题，有返回"),
        ),
      ),
    );
  }
}