flutter例子08

#例子01

import 'package:flutter/material.dart';

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

class RowWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter",
      home: Scaffold(
        appBar: AppBar(
          title: Text("Row示例"),
        ),
        body: Padding(
          padding: EdgeInsets.all(40.0),
          child: Row(
            children: <Widget>[
              Text("Android进阶之光"),
              Text("Android进阶解密"),
            ],
          ),
        ),
      ),
    );
  }
}

#例子02

import 'package:flutter/material.dart';

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

class RowWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter",
      home: Scaffold(
        appBar: AppBar(
          title: Text("Row示例"),
        ),
        body: Padding(
          padding: EdgeInsets.all(40.0),
          child: Row(
            children: <Widget>[
              Text("Android进阶之光"),
              Text("Android进阶解密"),
            ],
          ),
        ),
      ),
    );
  }
}

#例子03

import 'package:flutter/material.dart';

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

class StackWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter",
      home: Scaffold(
        appBar: AppBar(
          title: Text("层式布局示例"),
        ),
        body: Stack(
          fit: StackFit.expand,
          children: <Widget>[
            Positioned(
              left: 90.0,
              top: 120.0,
              child: Image.asset(
                "images/hao.jpg",
                width: 200.0,
                fit: BoxFit.cover,
              ),
            ),
            Container(
              child: Text('Android进阶三部曲第二部',
                  style: TextStyle(
                      color: Colors.lightBlue, fontSize: 20.0)),
              height: 50.0,
              width: 100.0,
              alignment: Alignment.center,
            )
          ],
        ),
      ),
    );
  }
}

#例子04

import 'package:flutter/material.dart';

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

class FlexWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Flutter",
      home: Scaffold(
        appBar: AppBar(
          title: Text("弹性布局示例"),
        ),
        body: Flex(
          direction: Axis.horizontal,//1
          children: <Widget>[
            Expanded(
              flex: 1,
              child: Container(
                height: 60.0,
                width: 30.0,
                color: Colors.red,
              ),
            ),
            Expanded(
              flex: 3,
              child: Container(
                height: 60.0,
                width: 30.0,
                color: Colors.yellow,
              ),
            ),
            Expanded(
              flex: 1,
              child: Container(
                height: 60.0,
                width: 30.0,
                color: Colors.blue,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

#例子05

import 'dart:convert';
import 'dart:io';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  var _ipAddress = 'Unknown';

  _getIPAddress() async {//1
    var url = 'https://httpbin.org/ip';
    Dio _dio = Dio();
    String result;
    try {
      var response = await _dio.get(url);//2
      if (response.statusCode == HttpStatus.ok) {
        var data= jsonDecode(response.toString());//3
        result = data['origin'];
      } else {
        result =
        'Error getting IP status ${response.statusCode}';
      }
    } catch (exception) {
      result =exception.toString();
    }
    if (!mounted) return;
    setState(() {
      _ipAddress = result;//4
    });
  }

  @override
  Widget build(BuildContext context) {
    var spacer = SizedBox(height: 10.0);
    return Scaffold(
      body: Padding(
        padding: EdgeInsets.all(100.0),
        child: Column(
          children: <Widget>[
            Text('IP地址为：'),
            spacer,
            Text('$_ipAddress'),
            spacer,
           RaisedButton(
              onPressed: _getIPAddress,
              child: Text('请求网络'),
            ),
          ],
        ),
      ),
    );
  }
}