stack_page_view

Description:

stack page view

You can use the PageView keeping position of items in Android and IOS.
Features #
Implementing a headered pageview form in Flutter is not as easy as you might think.
There is a problem in that when scrolling up and down on a specific page item, it scrolls up and down to other page items.
And when you switch tabs, the position on each page is not maintained and sometimes initialized.
StackPageView was created to solve this problem.
Video #

import 'package:flutter/material.dart';
import 'package:stack_pageview/stackPageView/stackPageViewInterface.dart';

import 'pageItem/pageItem.dart';
import 'stackPageView/stackPageView.dart';

class Home extends StatefulWidget {
const Home({Key? key}) : super(key: key);

@override
_HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
late TabController _tabController;

final List<String> _tabLabels = ["Tab A", "Tab B", "Tab C"];

List<ScrollController> scrollControllers = [];

StackPageViewInterface? interface;

@override
void initState() {
_tabController = TabController(
length: _tabLabels.length,
vsync: this,
animationDuration: const Duration(milliseconds: 200));
for (var o in _tabLabels) {
scrollControllers.add(ScrollController());
}
super.initState();
}

@override
void dispose() {
_tabController.dispose();
for (int i = 0; i < _tabLabels.length; i++) {
scrollControllers[i].dispose();
}
super.dispose();
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("StackPageView"),
elevation: 0,
),
body: Column(
children: [
Expanded(
child: StackPageView(
header: _header(),
headerHeight: 100,
tabBar: _tabBar(),
timerPeriodic: 1,
tabController: _tabController,
scrollControllers: scrollControllers,
interface: (interface) => this.interface = interface,
tabBarViews: _tabBarView(),
dragY: 10,
controller: (controller) {},
tabBarBackground: _tabDivider(),
tabBarBackgroundColor: Colors.white,
),
),
_button(),
],
),
);
}

Widget _header() {
return Container(
color: Colors.blue,
height: 100,
child: const Center(
child: Text(
"Header",
style: TextStyle(fontSize: 30, color: Colors.white),
),
),
);
}

TabBar _tabBar() {
return TabBar(
controller: _tabController,
indicatorColor: Colors.black,
labelColor: Colors.black,
unselectedLabelColor: Colors.grey,
tabs: List.generate(_tabLabels.length, (index) {
return SizedBox(
height: 45,
child: Center(child: Text(_tabLabels[index])),
);
}),
);
}

List<Widget> _tabBarView() {
return [
PageItem(
text: "Tab A",
scrollController: scrollControllers[0],
),
PageItem(
text: "Tab B",
scrollController: scrollControllers[1],
),
PageItem(
text: "Tab C",
scrollController: scrollControllers[2],
),
];
}

Widget _button() {
return Row(
children: [
ElevatedButton(
onPressed: () {
print('interface : $interface');
interface?.goTop();
},
child: const Text("Go top"),
),
ElevatedButton(
onPressed: () => interface?.goBottom(),
child: const Text("Go bottom"),
),
],
);
}

/// 탭바 하단에 있는 divider widget
Widget _tabDivider() {
return const Positioned(
left: 0,
right: 0,
bottom: 0,
child: Divider(
height: 2,
thickness: 2,
color: Colors.grey,
),
);
}
}




class PageItem extends StatefulWidget {
PageItem({
required this.text,
required this.scrollController,
Key? key,
}) : super(key: key);
String text;
ScrollController scrollController;

@override
_PageItemState createState() => _PageItemState();
}

class _PageItemState extends State<PageItem> {
int itemCount = 30;

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

@override
Widget build(BuildContext context) {
return ListView.builder(
physics: const ClampingScrollPhysics(),
padding: const EdgeInsets.only(bottom: 100),
controller: widget.scrollController,
itemCount: itemCount,
itemBuilder: (context, index) {
if (index == itemCount - 1) addData();
return SizedBox(
width: double.infinity,
height: 50,
child: Text("${widget.text} : ${index.toString()}"),
);
},
);
}

addData() async {
if (!mounted) return;
await Future.delayed(const Duration(milliseconds: 300));
setState(() {
itemCount += 20;
});
}
}


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Additional information #