Flutter scroll component drop-down refresh and pull up load

Intro

a widget provided to the flutter scroll component drop-down refresh and pull up load.support android and ios. If you are Chinese,click here(中文文档)

Download Demo(Android):

Features

• pull up load and pull down refresh
• It’s almost fit for all Scroll witgets,like GridView,ListView…
• provide global setting of default indicator and property
• provide some most common indicators
• Support Android and iOS default ScrollPhysics,the overScroll distance can be controlled,custom spring animate,damping,speed.
• horizontal and vertical refresh,support reverse ScrollView also(four direction)
• provide more refreshStyle: Behind,Follow,UnFollow,Front,provide more loadmore style
• Support twoLevel refresh,implments just like TaoBao twoLevel,Wechat TwoLevel
• enable link indicator which placing other place,just like Wechat FriendCircle refresh effect

Usage

add this line to pubspec.yaml

   dependencies:
     pull_to_refresh: ^1.5.7

import package

    import 'package:pull_to_refresh/pull_to_refresh.dart';

simple example,In addition, you should pay attention to the differences in what components SmartRefresher children store, and there are many such issues. If you are not sure child usage, see here

  List<String> items = ["1", "2", "3", "4", "5", "6", "7", "8"];
  RefreshController _refreshController =
      RefreshController(initialRefresh: false);

  void _onRefresh() async{
    // monitor network fetch
    await Future.delayed(Duration(milliseconds: 1000));
    // if failed,use refreshFailed()
    _refreshController.refreshCompleted();
  }

  void _onLoading() async{
    // monitor network fetch
    await Future.delayed(Duration(milliseconds: 1000));
    // if failed,use loadFailed(),if no data return,use LoadNodata()
    items.add((items.length+1).toString());
    if(mounted)
    setState(() {

    });
    _refreshController.loadComplete();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SmartRefresher(
        enablePullDown: true,
        enablePullUp: true,
        header: WaterDropHeader(),
        footer: CustomFooter(
          builder: (BuildContext context,LoadStatus mode){
            Widget body ;
            if(mode==LoadStatus.idle){
              body =  Text("pull up load");
            }
            else if(mode==LoadStatus.loading){
              body =  CupertinoActivityIndicator();
            }
            else if(mode == LoadStatus.failed){
              body = Text("Load Failed!Click retry!");
            }
            else if(mode == LoadStatus.canLoading){
                body = Text("release to load more");
            }
            else{
              body = Text("No more Data");
            }
            return Container(
              height: 55.0,
              child: Center(child:body),
            );
          },
        ),
        controller: _refreshController,
        onRefresh: _onRefresh,
        onLoading: _onLoading,
        child: ListView.builder(
          itemBuilder: (c, i) => Card(child: Center(child: Text(items[i]))),
          itemExtent: 100.0,
          itemCount: items.length,
        ),
      ),
    );
  }

  // from 1.5.0, it is not necessary to add this line
  //@override
 // void dispose() {
    // TODO: implement dispose
  //  _refreshController.dispose();
  //  super.dispose();
 // }

The global configuration RefreshConfiguration, which configures all Smart Refresher representations under the subtree, is generally stored at the root of MaterialApp and is similar in usage to ScrollConfiguration. In addition, if one of your SmartRefresher behaves differently from the rest of the world, you can use RefreshConfiguration.copyAncestor() to copy attributes from your ancestor RefreshConfiguration and replace attributes that are not empty.

    // Smart Refresher under the global configuration subtree, here are a few particularly important attributes
     RefreshConfiguration(
         headerBuilder: () => WaterDropHeader(),        // Configure the default header indicator. If you have the same header indicator for each page, you need to set this
         footerBuilder:  () => ClassicFooter(),        // Configure default bottom indicator
         headerTriggerDistance: 80.0,        // header trigger refresh trigger distance
         springDescription:SpringDescription(stiffness: 170, damping: 16, mass: 1.9),         // custom spring back animate,the props meaning see the flutter api
         maxOverScrollExtent :100, //The maximum dragging range of the head. Set this property if a rush out of the view area occurs
         maxUnderScrollExtent:0, // Maximum dragging range at the bottom
         enableScrollWhenRefreshCompleted: true, //This property is incompatible with PageView and TabBarView. If you need TabBarView to slide left and right, you need to set it to true.
         enableLoadingWhenFailed : true, //In the case of load failure, users can still trigger more loads by gesture pull-up.
         hideFooterWhenNotFull: false, // Disable pull-up to load more functionality when Viewport is less than one screen
         enableBallisticLoad: true, // trigger load more by BallisticScrollActivity
        child: MaterialApp(
            ........
        )
    );

1.5.6 add new feather: localization ,you can add following code in MaterialApp or CupertinoApp:

    MaterialApp(
            localizationsDelegates: [
              // this line is important
              RefreshLocalizations.delegate,
              GlobalWidgetsLocalizations.delegate,
              GlobalMaterialLocalizations.delegate
            ],
            supportedLocales: [
              const Locale('en'),
              const Locale('zh'),
            ],
            localeResolutionCallback:
                (Locale locale, Iterable<Locale> supportedLocales) {
              //print("change language");
              return locale;
            },
    )

ScreenShots