//下拉刷新组件const RefreshIndicator({Key key,@required this.child,this.displacement: 40.0, //触发下拉刷新的距离@required this.onRefresh, //下拉回调方法,方法需要有async和await关键字，没有await，刷新图标立马消失，没有async，刷新图标不会消失this.color, //进度指示器前景色，默认为系统主题色this.backgroundColor, //背景色this.notificationPredicate: defaultScrollNotificationPredicate,})

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';class ListViewPage extends StatefulWidget {@overrideListViewPageState createState() => new ListViewPageState();
}class ListViewPageState extends State<ListViewPage> {List list = new List(); //列表要展示的数据@overridevoid initState() {super.initState();getData();}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text('AndBlog'),),body: RefreshIndicator(onRefresh: _onRefresh,child: ListView.builder(itemCount: list.length,itemBuilder: (BuildContext context, int index) {return ListTile(title: Text(list[index]),);},)),floatingActionButton: FloatingActionButton(tooltip: 'Increment',child: Icon(Icons.account_box),onPressed: () {print("FloatingActionButton");},elevation: 30,), // This trailing comma makes auto-formatting nicer for build methods.);}Future<Null> _onRefresh() async {await Future.delayed(Duration(seconds: 3), () {print('refresh');setState(() {list = List.generate(20, (i) => '哈喽，我是下拉刷新的数据 $i');});});}Future getData() async {await Future.delayed(Duration(seconds: 2), () {setState(() {list = List.generate(30, (i) => '哈喽，我是原始数据 $i');});});}
}

import 'package:flutter/material.dart';
import 'package:flutter_andblog/andblog/common/color_common.dart';
import 'package:flutter_andblog/andblog/common/http_common.dart';
import 'package:flutter_andblog/andblog/detail/blog_detail_page.dart';
import 'package:http/http.dart' as http;
import 'blog.dart';class BlogListPage extends StatefulWidget {@overrideBlogListPageState createState() => new BlogListPageState();
}class BlogListPageState extends State<BlogListPage> {List<Blog> _blogList = [];String loadMoreText = "正在加载中...";TextStyle loadMoreTextStyle =new TextStyle(color: const Color(0xFF4483f6), fontSize: 14.0);ScrollController scrollController = new ScrollController();var hasData = true;var page = 0;@overridevoid initState() {super.initState();//一进页面就请求接口_getBlogListData();scrollController.addListener(() {if (scrollController.position.pixels ==scrollController.position.maxScrollExtent) {//已经滑到底了if (hasData) {//还有数据，加载下一页setState(() {loadMoreText = "正在加载中...";loadMoreTextStyle =new TextStyle(color: const Color(0xFF4483f6), fontSize: 14.0);});page++;print("page=" + page.toString());_getBlogListData();} else {setState(() {loadMoreText = "没有更多数据";loadMoreTextStyle =new TextStyle(color: const Color(0xFF999999), fontSize: 14.0);});}}});}@overridevoid dispose() {scrollController.dispose();super.dispose();}//网络请求Future _getBlogListData() async {//一页加载8条数据，skip为跳过的数据，比如加载第二页（page=1），skip跳过前8条数据，即显示第9-16条数据var skip = page * 8;print("blog_list_url=" + HttpCommon.blog_list_url + skip.toString());var response = await http.get(HttpCommon.blog_list_url + skip.toString(),headers: HttpCommon.headers());if (response.statusCode == 200) {// setState 相当于 runOnUiThreadsetState(() {var data = Blog.decodeData(response.body);if (data.length < 8) {//某页数据小于8，表明没有下一页了hasData = false;} else {hasData = true;}_blogList.addAll(data);print("_blogList.length0=" + _blogList.length.toString());});}}@overrideWidget build(BuildContext context) {var content;if (_blogList.length == 0) {content = new Center(// 可选参数 child:child: new CircularProgressIndicator(),);} else {content = _contentList();}return Scaffold(backgroundColor: ColorCommon.backgroundColor,appBar: AppBar(title: Text('AndBlog'),),body: content,floatingActionButton: FloatingActionButton(tooltip: 'Increment',child: Icon(Icons.account_box),onPressed: () {print("FloatingActionButton");},elevation: 30,), // This trailing comma makes auto-formatting nicer for build methods.);}Widget _contentList() {print("_blogList.length=" + _blogList.length.toString());return new RefreshIndicator(onRefresh: _onRefresh,child: ListView.builder(itemCount: _blogList.length + 1,itemBuilder: (BuildContext context, int index) {if (index == _blogList.length) {return _buildProgressMoreIndicator();} else {return _blogItem(index);}},controller: scrollController,));}Future<Null> _onRefresh() async {await Future.delayed(Duration(seconds: 1), () {print('refresh');setState(() {page = 0;_blogList.clear();_getBlogListData();});});}Widget _buildProgressMoreIndicator() {return new Padding(padding: const EdgeInsets.all(15.0),child: new Center(child: new Text(loadMoreText, style: loadMoreTextStyle),),);}Widget _blogItem(int index) {Blog blog = _blogList[index];var date = new Padding(padding: const EdgeInsets.only(top: 20.0,left: 10.0,right: 10.0,),child: new Text(blog.date,textAlign: TextAlign.center,style: TextStyle(color: ColorCommon.dateColor, fontSize: 18),));var cover = new Padding(padding: const EdgeInsets.only(top: 10.0,left: 10.0,right: 10.0,),child: new ClipRRect(borderRadius: BorderRadius.only(topLeft: Radius.circular(10.0),topRight: Radius.circular(10.0)),child: new Image.network('http://pic1.win4000.com/wallpaper/2020-04-21/5e9e676001e20.jpg',)));var title = new Text(blog.title,style: TextStyle(color: ColorCommon.titleColor, fontSize: 22),);var summary = new Padding(padding: const EdgeInsets.only(top: 5.0,),child: new Text(blog.summary,textAlign: TextAlign.left,style: TextStyle(color: ColorCommon.summaryColor, fontSize: 18)));var titleSummary = new Container(padding: const EdgeInsets.all(10.0),alignment: Alignment.topLeft,decoration: new BoxDecoration(color: Colors.white,borderRadius: BorderRadius.only(bottomLeft: Radius.circular(10.0),bottomRight: Radius.circular(10.0)),shape: BoxShape.rectangle,),margin: const EdgeInsets.only(left: 10, right: 10.0),child: Column(crossAxisAlignment: CrossAxisAlignment.start,mainAxisSize: MainAxisSize.min,children: <Widget>[title, summary],),);var blogItem = new GestureDetector(//点击事件onTap: () => navigateToMovieDetailPage(blog.objectId, index),child: new Column(children: <Widget>[date,cover,titleSummary,],),);return blogItem;}// 跳转页面navigateToMovieDetailPage(String blogId, Object imageTag) {Navigator.of(context).push(new MaterialPageRoute(builder: (BuildContext context) {return new BlogDetailPage(blogId, imageTag: imageTag);}));}
}