how to use it with NestedScrollView

[fangshengfy]

`import 'dart:async';

import 'package:intl/intl.dart';
import 'package:flutter/material.dart';
import 'package:sticky_infinite_list/sticky_infinite_list.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(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
routes: {
SingleChildScrollPage.ROUTE: (_) => SingleChildScrollPage(),
},
);
}
}

class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);

// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.

// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".

final String title;

@OverRide
_MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State {
final StreamController _streamController = StreamController.broadcast();
final ScrollController _scrollController = ScrollController();
Settings _settings = Settings();

@OverRide
Widget build(BuildContext context) => Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return [SliverAppBar(
expandedHeight: 230.0,
pinned: true,
flexibleSpace: FlexibleSpaceBar(
title: Text('复仇者联盟'),
background: Image.network(
'http://img.haote.com/upload/20180918/2018091815372344164.jpg',
fit: BoxFit.fitHeight,
),
),
)];
},
body:
ScrollWidget(
settings: _settings,
scrollController: _scrollController,
stream: _streamController.stream,
),
)
,
);

@OverRide
void dispose() {
super.dispose();

_streamController.close();

}
}

class ScrollWidget extends StatelessWidget {
final Stream stream;
final ScrollController scrollController;
final Settings settings;

const ScrollWidget({
Key key,
this.stream,
this.scrollController,
this.settings,
}) : super(key: key);

@OverRide
Widget build(BuildContext context) => InfiniteList(
/// when direction changes dynamically, Flutter
/// won't rerender scroll completely,
/// which means that gesture detector on scroll itself
/// remains from original direction
key: Key(settings.scrollDirection.toString()),
scrollDirection: settings.scrollDirection,
anchor: settings.anchor,
controller: scrollController,
direction: settings.multiDirection ? InfiniteListDirection.multi : InfiniteListDirection.single,
negChildCount: settings.negCount,
posChildCount: settings.posCount,
physics: settings.physics,
builder: (context, index) {
final date = DateTime.now().add(
Duration(
days: index,
)
);

  if (settings.overlay) {
    return InfiniteListItem.overlay(
      mainAxisAlignment: settings.mainAxisAlignment,
      crossAxisAlignment: settings.crossAxisAlignment,
      headerStateBuilder: (context, state) => Padding(
        padding: const EdgeInsets.all(8.0),
        child: Container(
          decoration: BoxDecoration(
            shape: BoxShape.circle,
            color: Colors.orange.withOpacity(1 - state.position),
          ),
          height: 70,
          width: 70,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(
                date.day.toString(),
                style: TextStyle(
                  fontSize: 21,
                  color: Colors.black87,
                  fontWeight: FontWeight.w600,
                ),
              ),
              Text(
                DateFormat.MMM().format(date),
                style: TextStyle(
                  height: .7,
                  fontSize: 17,
                  color: Colors.black87,
                  fontWeight: FontWeight.w400,
                ),
              )
            ],
          ),
        ),
      ),
      contentBuilder: (context) => Padding(
        padding: const EdgeInsets.all(8.0),
        child: Container(
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10),
            color: Colors.blueAccent,
          ),
          height: settings.contentHeight,
          width: settings.contentWidth,
          child: Center(
            child: Text(
              DateFormat.yMMMMd().format(date),
              style: TextStyle(
                  fontSize: 18,
                  color: Colors.white
              ),
            ),
          ),
        ),
      ),
    );
  }

  return InfiniteListItem(
    mainAxisAlignment: settings.mainAxisAlignment,
    crossAxisAlignment: settings.crossAxisAlignment,
    positionAxis: settings.positionAxis,
    headerStateBuilder: (context, state) => Padding(
      padding: const EdgeInsets.all(8.0),
      child: Container(
        decoration: BoxDecoration(
          shape: BoxShape.circle,
          color: Colors.orange.withOpacity(1 - state.position),
        ),
        height: 70,
        width: 70,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              date.day.toString(),
              style: TextStyle(
                fontSize: 21,
                color: Colors.black87,
                fontWeight: FontWeight.w600,
              ),
            ),
            Text(
              DateFormat.MMM().format(date),
              style: TextStyle(
                height: .7,
                fontSize: 17,
                color: Colors.black87,
                fontWeight: FontWeight.w400,
              ),
            )
          ],
        ),
      ),
    ),
    contentBuilder: (context) => Padding(
      padding: const EdgeInsets.all(8.0),
      child: Container(
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(10),
          color: Colors.blueAccent,
        ),
        height: settings.contentHeight,
        width: settings.contentWidth,
        child: Center(
          child: Text(
            DateFormat.yMMMMd().format(date),
            style: TextStyle(
                fontSize: 18,
                color: Colors.white
            ),
          ),
        ),
      ),
    ),
  );
},

);

}

enum ScrollPhysicsEnum {
PLATFORM,
IOS,
ANDROID,
}

class Settings {
int negCount;
int posCount;
bool multiDirection;
HeaderMainAxisAlignment mainAxisAlignment;
HeaderCrossAxisAlignment crossAxisAlignment;
HeaderPositionAxis positionAxis;
double anchor;
Axis scrollDirection;
ScrollPhysicsEnum physicsType;
bool overlay;

bool get scrollVertical => scrollDirection == Axis.vertical;

ScrollPhysics get physics {
switch (physicsType) {
case ScrollPhysicsEnum.PLATFORM:
return null;

  case ScrollPhysicsEnum.ANDROID:
    return ClampingScrollPhysics();

  case ScrollPhysicsEnum.IOS:
    return BouncingScrollPhysics();
}

return null;

}

double get contentHeight {
if (scrollVertical) {
return 300;
}

return double.infinity;

}

double get contentWidth {
if (scrollVertical) {
return double.infinity;
}

return 300;

}

Settings({
this.negCount,
this.posCount,
this.mainAxisAlignment = HeaderMainAxisAlignment.start,
this.crossAxisAlignment = HeaderCrossAxisAlignment.start,
this.positionAxis = HeaderPositionAxis.mainAxis,
this.multiDirection = false,
this.anchor = 0,
this.scrollDirection = Axis.vertical,
this.physicsType = ScrollPhysicsEnum.PLATFORM,
this.overlay = false,
});
}

class SingleChildScrollPage extends StatefulWidget {
static const String ROUTE = "/single-child";

@OverRide
_SingleChildScrollPageState createState() => _SingleChildScrollPageState();
}

class _SingleChildScrollPageState extends State {
static const double _headerHeight = 50;

final StreamController<StickyState> _headerStream = StreamController<StickyState>.broadcast();
final StreamController<StickyState> _headerOverlayStream = StreamController<StickyState>.broadcast();

@OverRide
Widget build(BuildContext context) {
final height = MediaQuery.of(context).size.height;

return Scaffold(
  appBar: AppBar(
    title: const Text('Single element example'),
  ),
  body: SingleChildScrollView(
    child: Column(
      children: <Widget>[
        Container(
          height: height,
          color: Colors.lightBlueAccent,
          child: Placeholder(),
        ),
        StickyListItem<String>(
          streamSink: _headerStream.sink,
          header: Container(
            height: _headerHeight,
            width: double.infinity,
            color: Colors.orange,
            child: Center(
              child: StreamBuilder<StickyState<String>>(
                stream: _headerStream.stream,
                builder: (_, snapshot) {
                  if (!snapshot.hasData) {
                    return Container();
                  }

                  final position = (snapshot.data.position * 100).round();

                  return Text('Positioned relative. Position: $position%');
                },
              ),
            ),
          ),
          content: Container(
            height: height,
            color: Colors.blueAccent,
            child: Placeholder(),
          ),
          itemIndex: "single-child",
        ),
        StickyListItem<String>.overlay(
          streamSink: _headerOverlayStream.sink,
          header: Container(
            height: _headerHeight,
            width: double.infinity,
            color: Colors.orange,
            child: Center(
              child: StreamBuilder<StickyState<String>>(
                stream: _headerOverlayStream.stream,
                builder: (_, snapshot) {
                  if (!snapshot.hasData) {
                    return Container();
                  }

                  final position = (snapshot.data.position * 100).round();

                  return Text('Positioned overlay. Position: $position%');
                },
              ),
            ),
          ),
          content: Container(
            height: height,
            color: Colors.lightBlueAccent,
            child: Placeholder(),
          ),
          itemIndex: "single-overlayed-child",
        ),
        Container(
          height: height,
          color: Colors.cyan,
          child: Placeholder(),
        ),
      ],
    ),
  ),
);

}

@OverRide
void dispose() {
super.dispose();

_headerStream.close();
_headerOverlayStream.close();

}
}`

maybe scroll has poblem