list_data_cache_manager 0.0.1

A new Flutter package project.

example/lib/main.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:list_data_cache_manager/default_list_cache_manager.dart';
import 'package:list_data_cache_manager/list_data_cache_manager.dart';
import 'package:pull_to_refresh/pull_to_refresh.dart';

import 'model/list_model.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: ListDataPage(),
    );
  }
}

const PageCount = 50;

class ListDataPage extends StatefulWidget {
  @override
  _ListDataPageState createState() => _ListDataPageState();
}

class _ListDataPageState extends State<ListDataPage> {
  DefaultListCacheManager<ListItemInfoModel> _dataCacheManager;
  RefreshController _refreshController = RefreshController(initialRefresh: true);
  StreamController<int> _streamController = StreamController<int>();

  @override
  void initState() {
    super.initState();
    _streamController.add(0);

    ///初始化缓存管理控件，设置模型转换方法
    _dataCacheManager = DefaultListCacheManager<ListItemInfoModel>(
      modelFromJson: (json) => ListItemInfoModel.fromJson(json),
      modelToJson: (model) => model.toJson(),
      requestNetworkData: (int startIndex) {
        ///加载网络数据
        getData(startIndex);
      },
    );
  }

  void getData(int startIndex) {
    Future.delayed(Duration(seconds: 1), () {
    if (_refreshController.isRefresh) {
      _refreshController.refreshCompleted();
    }
    if (_refreshController.isLoading) {
      _refreshController.loadComplete();
    }

    ///判断是否下拉刷新
    if (startIndex == 0) {
      _dataCacheManager.clear();

      ///清除nodata，以便可以继续上拉加载更多
      _refreshController.loadComplete();
    }

    // ///判断是否无更多数据
    // if (startIndex > 90) {
    //   _refreshController.loadNoData();

    //   ///禁止_dataCacheManager发起的网络请求
    //   _dataCacheManager.unableNetworkLoading();
    // } else {
    ///请求数据结束后允许_dataCacheManager发起网络请求,也就是允许再次调用requestNetworkData
    _dataCacheManager.enableNetworkLoading();
    // }

    List<ListItemInfoModel> result = [];
    List.generate(PageCount, (index) => result.add(ListItemInfoModel(value: index + startIndex)));
    if (_dataCacheManager.itemCount == startIndex) {
      _dataCacheManager.addAll(result);
      setState(() {});
    }
    });
  }

  @override
  void dispose() {
    _streamController.close();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('列表数据管理'),
      ),
      body: Column(
        children: [
          Container(
            height: 40,
            width: BoxConstraints.expand().maxWidth,
            color: Colors.red,
            alignment: Alignment.center,
            child: StreamBuilder(
              stream: _streamController.stream,
              builder: (_, __) =>
                  Text('缓存数据${_dataCacheManager.firstCacheItem?.index}->${_dataCacheManager.lastCacheItem?.index}'),
            ),
          ),
          Expanded(
            child: NotificationListener<ScrollNotification>(
              onNotification: (notification) {
                // print(notification);
                _streamController.add(0);
                return true;
              },
              child: SmartRefresher(
                // header: defaultRefreshHeader(),
                // footer: defaultRefreshFooter(),
                enablePullUp: _dataCacheManager.itemCount > 0,
                controller: _refreshController,
                onRefresh: () {
                  getData(0);
                },
                onLoading: () {
                  if (!_dataCacheManager.isLoadingNetworkData) {
                    _dataCacheManager.unableNetworkLoading();
                    getData(_dataCacheManager.itemCount);
                  }
                },
                child: ListView.separated(
                  itemCount: _dataCacheManager.itemCount,
                  itemBuilder: (_, index) {
                    ListCacheItem<ListItemInfoModel> item = _dataCacheManager.dataAtIndex(index);
                    return ListCacheBuilder<ListItemInfoModel>(
                      builder: (cacheItem, _) {
                        ListItemInfoModel info = cacheItem?.data;
                        return Container(
                          height: 40,
                          alignment: Alignment.center,
                          child: Text('${info?.value}'),
                          // child:Text('hello'),
                        );
                      },
                      cacheItem: item,
                    );
                  },
                  separatorBuilder: (_, __) => Divider(
                    height: 1,
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}