CLOSED: NestedScrollView briefly stutters before properly scrolling - flutter

So basically I am using a NestedScrollView which has a TabBarView as its body. My setup works pretty much as desired however there is a stutter while scrolling. When the TabBar reaches the top of the page/touches the bottom of the SliverAppBar while scrolling, there is a brief pause in scrolling before scrolling is resumed as normal. This pause also happens when we scroll back down.
Here is the error:
I cannot seem to figure out how to fix this pause. It is brief yet annoyingly noticeable. How could I fix this?
Thank you!

You can use only one CustomScrollView in this case. and For inner scrollable physics: NeverScrollableScrollPhysics(),
Widget build(BuildContext context) {
return Scaffold(
body: CustomScrollView(
slivers: [
const SliverAppBar(
pinned: true,
title: Text('AppBar'),
collapsedHeight: 100,
backgroundColor: Colors.blue,
),
SliverToBoxAdapter(
child: Container(
alignment: Alignment.center,
height: 100,
color: Colors.redAccent,
child: const Text('Container'),
),
),
SliverPinnedHeader(
child: Container(
color: Colors.white,
child: TabBar(
controller: _tabController,
tabs: const [
Tab(icon: Icon(Icons.shopping_cart, color: Colors.black)),
Tab(icon: Icon(Icons.bookmark, color: Colors.black)),
],
),
),
),
SliverFillRemaining(
child: TabBarView(
// physics: NeverScrollableScrollPhysics(),
controller: _tabController,
children: [
ListView.builder(
itemCount: 44,
physics: NeverScrollableScrollPhysics(),
itemBuilder: (context, index) {
return ListTile(
tileColor: Colors.pinkAccent,
title: Text('index $index'),
);
},
),
ListView.builder(
itemCount: 44,
physics: NeverScrollableScrollPhysics(),
itemBuilder: (context, index) {
return ListTile(
tileColor: Colors.pinkAccent,
title: Text('index $index'),
);
},
),
],
)),
],
));
}

Related

Scroll To Index in ListView Flutter

In my application I am listing in an appBar several Containers that have the names of product categories, these categories are being listed in the body with their respective products.
The ListView that is in the appBar has the same indexes of the ListView of the body, so the idea was to press the index 'x' in the appBar and the user would be redirected to the index 'x' in the body.
I tried many solutions, one of then was the package https://pub.dev/packages/scrollable_positioned_list, but it did not works because when calling the function to scroll my list just disappears.
Here's de code:
return Scaffold(
backgroundColor: Colors.white,
appBar: PreferredSize(
preferredSize: Size.fromHeight(120),
child: Column(
children: [
AppBar(...),
Expanded(
child: Container(
color: AppColors.primary,
child: ListView.builder(
scrollDirection: Axis.horizontal,
itemCount: widget.listaProdutos.length,
itemBuilder: (context, index) {
return Padding(
padding: EdgeInsets.symmetric(...),
child: GestureDetector(
child: Container(
decoration: BoxDecoration(...),
child: Padding(...),
child: Center(
child: Text(
widget.listaProdutos[index].dsGrupo,
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold,
),
),
),
),
),
onTap: () {
SHOULD SCROLL TO INDEX
},
),
);
},
)
),
),
],
),
),
body: SingleChildScrollView(
child: Column(
children: [
Container(
child: ListView.builder(
physics: NeverScrollableScrollPhysics(),
shrinkWrap: true,
itemCount: widget.listaProdutos.length,
itemBuilder: (context, indexGrupo) {
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Card(...),
ListView.builder(..),
],
);
},
),
),
],
),
),
);
You can use PageView with scrollDirection: Axis.vertical,
class TFW extends StatefulWidget {
const TFW({super.key});
#override
State<TFW> createState() => _TFWState();
}
class _TFWState extends State<TFW> {
final PageController controller = PageController();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
bottom: PreferredSize(
preferredSize: Size.fromHeight(100),
child: Expanded(
child: ListView.builder(
itemCount: 100,
scrollDirection: Axis.horizontal,
itemBuilder: (context, index) {
return InkWell(
onTap: () {
controller.animateToPage(index,
duration: Duration(milliseconds: 400),
curve: Curves.easeIn);
},
child: SizedBox(width: 100, child: Text("$index")),
);
},
),
),
)),
body: PageView.builder(
controller: controller,
itemCount: 100,
scrollDirection: Axis.vertical,
itemBuilder: (context, index) {
return Container(
color: index.isEven ? Colors.red : Colors.blue,
child: Text("$index"),
);
},
),
);
}
}
Fortunately I was able to resolve the problem. To help members who may have the same doubt I will register here the solution that worked for me. (sorry for the bad English)
Question: Why ScrollablePositionedList wasn't working? (as I mentioned iniatily)
Response: I was using the ScrollablePositionedList within a SingleChildScrollView, and for some reason when using the scrollTo or jumpTo function, the information that was visible simply disappeared. For that reason, I was trying to find a way to get success using a ListView (what came to nothing).
Solution: ... Trying to figure out why the ScrollablePositionedList wasn't working as it should ...
The initial structure was:
body: SingleChildScrollView(
child: Column(
children: [
Container(
child: ScrollablePositionedList.builder(
Changed for:
body: ScrollablePositionedList.builder(
The only reason for all this confusion is that ScrollablePositionedList's indexing functions for some reason don't work as they should if it's inside a SingleChildScrollView. So, take off SingleChildScrollView and all good.

Flutter listview scrolling is not available

I can see 6 list items in my listview widget and I can not scroll the listview although 3 more items are there.
Actually I want to keep this workouts page pretty simple that means I want to avoid using many rows/columns...
I have just a text label at the top left corner and below listview.
What do I have to change to make the listview scrolling?
I already use physics: AlwaysScrollableScrollPhysics(),
appBar: AppBar(
title: Text(title),
),
body: Container(
color: Colors.green,
margin: const EdgeInsets.all(5.0),
child: Column(
children: [
Align(
alignment: Alignment.topLeft,
child: Text("Workouts", style: TextStyle(fontWeight: FontWeight.bold, fontSize: 25)),
),
Expanded(
child: ListView.builder(
physics: AlwaysScrollableScrollPhysics(),
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount: workouts.length,
itemBuilder: (context, index) {
var workout = workouts[index];
return WorkoutWidget(key: Key(workout.id.toString()), workout: workout);
}),
),
],
),
),
Change physics to NeverScrollableScrollPhysics(), then wrap your Container with SingleChildScrollView widget. You could also omit scrollDirection, because Axis.vertical is already the default value.
appBar: AppBar(
title: Text(title),
),
body: SingleChildScrollView(
child: Container(
color: Colors.green,
margin: const EdgeInsets.all(5.0),
child: Column(
children: [
Align(
alignment: Alignment.topLeft,
child: Text(
"Workouts",
style: TextStyle(fontWeight: FontWeight.bold, fontSize: 25),
),
),
Expanded(
child: ListView.builder(
physics: NeverScrollableScrollPhysics(),
shrinkWrap: true,
itemCount: workouts.length,
itemBuilder: (context, index) {
var workout = workouts[index];
return WorkoutWidget(
key: Key(workout.id.toString()),
workout: workout,
);
}),
),
],
),
),

Flutter: ReorderableListView within CustomScrollView

I have this design:
CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
const SliverAppBar(
pinned: true,
expandedHeight: 250.0,
flexibleSpace: FlexibleSpaceBar(
title: Text('Demo'),
),
),
SliverList(
delegate: SliverChildListDelegate(
[
Text("sds"),
],
),
),
SliverGrid(
gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
maxCrossAxisExtent: 200.0,
mainAxisSpacing: 10.0,
crossAxisSpacing: 10.0,
childAspectRatio: 4.0,
),
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
return Container(
alignment: Alignment.center,
color: Colors.teal[100 * (index % 9)],
child: Text('Grid Item $index'),
);
},
childCount: 10,
),
),
SliverFillRemaining(
child: ReorderableListView(
scrollController: _scrollController,
children: <Widget>[
for (final items in item)
Card(
color: Colors.blueGrey,
key: ValueKey(items),
elevation: 2,
child: ListTile(
title: Text(items),
leading: Icon(
Icons.work,
color: Colors.black,
),
),
),
],
onReorder: reorderData,
),
),
],
),
Everything between the SliverAppBar and the ReorderableListView is just an example of how it should work.
I need to order some elements so for that I use a ReorderableListView but this needs to be inside a CustomScrollView and using its scroll. Right now everything works except for the scroll. The SliverAppBar minimises when scrolling over the grid, but the ReorderableListView has it owns scroll.
Is there any way to cancel the second scroll and having these 2 elements working together?
I also uses this library https://pub.dev/packages/reorderables but if you have a look to the repo it seems abandoned (and I faced different issues)

ItemList in an ItemList not scrolling

I have a nested ItemList that is made as follows:
SafeArea(
child: ListView(
padding: EdgeInsets.zero,
children: <Widget>[
ListTile(
title: Text('Placeholder'),
),
ListView.builder(
shrinkWrap: true,
itemCount: itemList.length,
itemBuilder: (BuildContext context, int index) {
final itemData = itemList[index];
return Card(
child: ListTile(
title: Container(
width: MediaQuery.of(context).size.width,
child: Text(
itemData.text,
maxLines: 1,
overflow: TextOverflow.ellipsis,
style: Theme.of(context).textTheme.headline5,
),
),
),
);
},
),
],
),
),
I can scroll up and down when holding the items directly placed in the first list, doing so also moves the items from the nested list. (wanted behavior)
When holding items in the sublist (the one with the builder), nothing moves anywhere.
I want to make so that all items move when any of them are held to scroll, how can I do that?
Is there a way to build a list without ListView.builder or did I miss some ListView parameters?
You could use the physics parameter of Listview to achive the intended result.
SafeArea(
child: ListView(
physics: AlwaysScrollableScrollPhysics(), // add this
padding: EdgeInsets.zero,
children: <Widget>[
ListTile(
title: Text('Placeholder'),
),
ListView.builder(
physics: NeverScrollableScrollPhysics(), // and this
shrinkWrap: true,
itemCount: itemList.length,
itemBuilder: (BuildContext context, int index) {
final itemData = itemList[index];
return Card(
child: ListTile(
title: Container(
width: MediaQuery.of(context).size.width,
child: Text(
itemData.text,
maxLines: 1,
overflow: TextOverflow.ellipsis,
style: Theme.of(context).textTheme.headline5,
),
),
),
);
},
),
],
),
)
Now your list should be scrollable.

How to scroll individual page when we use tabbar in flutter?

I want to make scrollable page in flutter when we use Tabbar in flutter.
I tried this code but this is not working.
In this code my whole listview I cannot see. How to display whole listview items while using tabbar.
So, how can I solve this problem.
Widget _listofitem() {
return Container(
margin: EdgeInsets.only(top: 10.0),
padding: EdgeInsets.all(8.0),
child: ListView.builder(
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
itemCount: categoryDetail.length,
itemBuilder: (BuildContext context, int index) {
return Container(
padding: EdgeInsets.all(8.0),
width: MediaQuery.of(context).size.width,
height: 100.0,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(10.0),
color: Colors.cyanAccent),
child: Column(
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Center(
child: SizedBox(
height: 20,
width: 20,
// child: NetworkImage(categoryDetail[index]),
),
),
SizedBox(
height: 10.0,
),
Text(categoryDetail[index]['category_name'].toString()),
],
),
);
},
),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title: Text(
'Invitation Card Application',
style: TextStyle(color: Colors.white),
),
backgroundColor: Colors.cyan,
centerTitle: true,
bottom: TabBar(
tabs: myTabs,
controller: _tabController,
)
),
body: TabBarView(
controller: _tabController,
children: myTabs.map((Tab tab) {
return Center(
child: Stack(
children: <Widget>[
_listofitem(),
// _ofitem()
],
),
);
}).toList(),
));
}
I want to change page on individual tab click and also do scroll in that individual page. So I display whole my page. What is the solution for it.
In the ListView.builder() widget you have set the property,
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
This is preventing the scroll on the list view. If you want to wrap the list view inside the container with the above properties, then wrap the container in the SingleChildScrollView widget.
SingleChildScrollView(
child: Container(),
);
By this, you can have the scroll effect and you will be able to see all the list view items