FlutterOSC/lib/pages/NewsListPage.dart

import 'dart:async';
import 'package:flutter/material.dart';
import '../util/NetUtils.dart';
import '../api/Api.dart';
import 'dart:convert';
import '../constants/Constants.dart';
import '../widgets/SlideView.dart';
import '../pages/NewsDetailPage.dart';
import '../widgets/CommonEndLine.dart';

class NewsListPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return NewsListPageState();
  }
}

class NewsListPageState extends State<NewsListPage> {
  var listData;
  var slideData;
  var curPage = 1;
  var listTotalSize = 0;
  ScrollController _controller = ScrollController();
  TextStyle titleTextStyle = TextStyle(fontSize: 15.0);
  TextStyle subtitleStyle = TextStyle(color: const Color(0xFFB5BDC0), fontSize: 12.0);

  NewsListPageState() {
    _controller.addListener(() {
      var maxScroll = _controller.position.maxScrollExtent;
      var pixels = _controller.position.pixels;
      if (maxScroll == pixels && listData.length < listTotalSize) {
        // scroll to bottom, get next page data
        print("load more ... ");
        curPage++;
        getNewsList(true);
      }
    });
  }

  @override
  void initState() {
    super.initState();
    getNewsList(false);
  }

  Future<Null> _pullToRefresh() async {
    curPage = 1;
    getNewsList(false);
    return null;
  }

  @override
  Widget build(BuildContext context) {
    if (listData == null) {
      return Center(
        child: CircularProgressIndicator(),
      );
    } else {
      Widget listView = ListView.builder(
        itemCount: listData.length * 2,
        itemBuilder: (context, i) => renderRow(i),
        controller: _controller,
      );
      return RefreshIndicator(child: listView, onRefresh: _pullToRefresh);
    }
  }

  getNewsList(bool isLoadMore) {
    String url = Api.NEWS_LIST;
    url += "?pageIndex=$curPage&pageSize=10";
    print("newsListUrl: $url");
    NetUtils.get(url).then((data) {
      if (data != null) {
        Map<String, dynamic> map = json.decode(data);
        if (map['code'] == 0) {
          var msg = map['msg'];
          listTotalSize = msg['news']['total'];
          var _listData = msg['news']['data'];
          var _slideData = msg['slide'];
          setState(() {
            if (!isLoadMore) {
              listData = _listData;
              slideData = _slideData;
            } else {
              List list1 = List();
              list1.addAll(listData);
              list1.addAll(_listData);
              if (list1.length >= listTotalSize) {
                list1.add(Constants.END_LINE_TAG);
              }
              listData = list1;

              slideData = _slideData;
            }
          });
        }
      }
    });
  }

  Widget renderRow(i) {
    if (i == 0) {
      return Container(
        height: 180.0,
        child: SlideView(slideData),
      );
    }
    i -= 1;
    if (i.isOdd) {
      return Divider(height: 1.0);
    }
    i = i ~/ 2;
    var itemData = listData[i];
    if (itemData is String && itemData == Constants.END_LINE_TAG) {
      return CommonEndLine();
    }
    var titleRow = Row(
      children: [
        Expanded(
          child: Text(itemData['title'], style: titleTextStyle),
        )
      ],
    );
    var timeRow = Row(
      children: [
        Container(
          width: 20.0,
          height: 20.0,
          decoration: BoxDecoration(
            shape: BoxShape.circle,
            color: const Color(0xFFECECEC),
            image: DecorationImage(
                image: NetworkImage(itemData['authorImg']), fit: BoxFit.cover),
            border: Border.all(
              color: const Color(0xFFECECEC),
              width: 2.0,
            ),
          ),
        ),
        Padding(
          padding: const EdgeInsets.fromLTRB(0.0, 0.0, 0.0, 0.0),
          child: Text(
            itemData['timeStr'],
            style: subtitleStyle,
          ),
        ),
        Expanded(
          flex: 1,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.end,
            children: [
              Text("${itemData['commCount']}", style: subtitleStyle),
              Image.asset('./images/ic_comment.png', width: 16.0, height: 16.0),
            ],
          ),
        )
      ],
    );
    var thumbImgUrl = itemData['thumb'];
    var thumbImg = Container(
      margin: const EdgeInsets.all(10.0),
      width: 60.0,
      height: 60.0,
      decoration: BoxDecoration(
        shape: BoxShape.circle,
        color: const Color(0xFFECECEC),
        image: DecorationImage(
            image: ExactAssetImage('./images/ic_img_default.jpg'),
            fit: BoxFit.cover),
        border: Border.all(
          color: const Color(0xFFECECEC),
          width: 2.0,
        ),
      ),
    );
    if (thumbImgUrl != null && thumbImgUrl.length > 0) {
      thumbImg = Container(
        margin: const EdgeInsets.all(10.0),
        width: 60.0,
        height: 60.0,
        decoration: BoxDecoration(
          shape: BoxShape.circle,
          color: const Color(0xFFECECEC),
          image: DecorationImage(
              image: NetworkImage(thumbImgUrl), fit: BoxFit.cover),
          border: Border.all(
            color: const Color(0xFFECECEC),
            width: 2.0,
          ),
        ),
      );
    }
    var row = Row(
      children: [
        Expanded(
          flex: 1,
          child: Padding(
            padding: const EdgeInsets.all(10.0),
            child: Column(
              children: [
                titleRow,
                Padding(
                  padding: const EdgeInsets.fromLTRB(0.0, 8.0, 0.0, 0.0),
                  child: timeRow,
                )
              ],
            ),
          ),
        ),
        Padding(
          padding: const EdgeInsets.all(6.0),
          child: Container(
            width: 100.0,
            height: 80.0,
            color: const Color(0xFFECECEC),
            child: Center(
              child: thumbImg,
            ),
          ),
        )
      ],
    );
    return InkWell(
      child: row,
      onTap: () {
        Navigator.of(context).push(MaterialPageRoute(
          builder: (ctx) => NewsDetailPage(id: itemData['detailUrl'])
        ));
      },
    );
  }
}