实战一

首页搭建
tabbar banner 滚动导航栏颜色渐变

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

const APPBAR_SCROLL_OFFSET = 100;
class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  double _appbarAlpha = 0.0;
  List<String> _imageUrls = [
    'http://file02.16sucai.com/d/file/2015/0128/8b0f093a8edea9f7e7458406f19098af.jpg',
    'http://b2-q.mafengwo.net/s5/M00/91/06/wKgB3FH_RVuATULaAAH7UzpKp6043.jpeg',
    'http://file02.16sucai.com/d/file/2015/0408/779334da99e40adb587d0ba715eca102.jpg',
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(children: <Widget>[
        MediaQuery.removePadding( // 移除widget边距
            removeTop: true,
            context: context,
            child: NotificationListener(
                onNotification: (scrollNotification) {
                  if (scrollNotification is ScrollUpdateNotification && scrollNotification.depth == 0) {
                    _onScroll(scrollNotification.metrics.pixels);
                  }
                  return true;
                },
                child: ListView(children: <Widget>[
                  Container(
                      height: 180,
                      child: Swiper(
                        itemCount: _imageUrls.length,
                        autoplay: true,
                        itemBuilder: (BuildContext context, int index) {
                          return Image.network(
                            _imageUrls[index],
                            fit: BoxFit.fill,
                          );
                        },
                        pagination: SwiperPagination(),
                      )),
                  Container(
                    child: Text('哈哈',),
                  ),
                ]))),
          Opacity(
            opacity: _appbarAlpha,
            child: Container(
              height: 80,
              decoration: BoxDecoration(color: Colors.white),
              child: Center(
                child: Padding(padding: EdgeInsets.only(top: 20),
                  child: Text('首页'),),
              ),
            ),
          ),
        ],
      ),
    );
  }

  void _onScroll(offset) {
    double alpha = offset / APPBAR_SCROLL_OFFSET;
    if (alpha < 0) {
      alpha = 0;
    } else if (alpha > 1) {
      alpha = 1;
    }
    setState(() {
      _appbarAlpha = alpha;
    });
    print(alpha);
  }
}

网络请求
http

数据模型转换
json_to_dart

异步加载
Future 和 FutureBuilder

本地存储
shared_preference