Develop Reference

How to scroll when + button is clicked in flutter?

I want when I click on the + Button it shows the next 3 containers that in the listVeiw it is horizontally direction.
Here is my code.
when I tap for the first time it works, but it doesn't work for the others taps
import 'package:flutter/material.dart';
class FindCars extends StatefulWidget {
const FindCars({Key? key}) : super(key: key);
#override
State<NewWayToFindCars> createState() => _NewWayToFindCarsState();
}
class _NewWayToFindCarsState extends State<NewWayToFindCars> {
var pricesListNumber = 10;
int counter = 1;
List months = [
'يناير',
'فبراير',
'مارس',
'ابريل',
'مايو',
'يونيو',
'يوليو',
'اغسطس',
'سبتمبر',
'اكتوبر',
'نوفمبر',
'ديسمبر'
];
var currentMonth = new DateTime.now().month;
var currentDay = new DateTime.now().day;
late ScrollController _scrollController;
#override
void initState() {
_scrollController = ScrollController();
super.initState();
}
#override
Widget build(BuildContext context) {
print(months[currentMonth - 1]);
print(currentDay);
print(DateTime.now());
return Container(
width: MediaQuery.of(context).size.width,
height: MediaQuery.of(context).size.height,
child: Directionality(
textDirection: TextDirection.rtl,
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Text(
'${months[currentMonth - 1]} 2022',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
color: Colors.black,
fontFamily: 'cairo',
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
InkWell(
onTap: () {
_scrollController.animateTo(-200,
duration: const Duration(milliseconds: 500),
curve: Curves.easeInOut);
},
child: Container(
child: Icon(Icons.remove, size: 22),
width: 50,
height: 50,
decoration: BoxDecoration(
color: Color(0xFFDCEDC8).withOpacity(0.5),
border: Border.all(
color: Color(0xFFDDE7DD).withOpacity(0.5),
width: 2.5,
),
borderRadius: BorderRadius.only(
topLeft: Radius.circular(10),
bottomLeft: Radius.circular(10),
),
),
),
),
InkWell(
onTap: () {
_scrollController.animateTo(200,
duration: const Duration(milliseconds: 500),
curve: Curves.easeInOut);
},
child: Container(
child: Center(child: Icon(Icons.add_sharp, size: 22)),
width: 50,
height: 50,
decoration: BoxDecoration(
color: Color(0xFFDCEDC8).withOpacity(0.25),
border: Border.all(
color: Color(0xFFDDE7DD).withOpacity(0.5),
width: 2.5,
),
borderRadius: BorderRadius.only(
topRight: Radius.circular(10),
bottomRight: Radius.circular(10),
),
),
),
),
],
),
Container(
width: MediaQuery.of(context).size.width,
height: MediaQuery.of(context).size.height * 0.1,
child: ListView(
controller: _scrollController, // scroll contoller
scrollDirection: Axis.horizontal,
children: new List.generate(
pricesListNumber,
(index) => Padding(
padding: const EdgeInsets.all(8.0),
child: Container(
child: Center(child: Text('${currentDay++}')),
decoration: BoxDecoration(
boxShadow: [
BoxShadow(
color: Colors.grey.withOpacity(0.5),
spreadRadius: 5,
blurRadius: 7,
offset: Offset(0, 3), // changes position of shadow
),
],
color: Color(0xFFDCEDC8).withOpacity(0.5),
border: Border.all(
color: Color(0xFFDDE7DD).withOpacity(0.5),
width: 2.5,
),
borderRadius: BorderRadius.circular(10),
),
height: 50,
width: MediaQuery.of(context).size.width * 0.25,
),
),
),
),
),
],
),
),
);
}
}
Here is my code for the UI, and now it is only works in the first click put it does not work until the end.
Can you please help me with that?

Attach a ScrollController to your scrollable widget and then use scrollController.animateTo(//offset) to reach where you want.
Do check the animateTo method on this page.
EDIT:
sample code:
ScrollController scrollController = ScrollController();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter'),
centerTitle: true,
),
body: Column(
children: [
ElevatedButton(
onPressed: () {
scrollController.animateTo(0,
duration: Duration(seconds: 1), curve: Curves.easeIn);
},
child: Text("go top")),
Expanded(
flex: 1,
child: ListView.builder(
controller: scrollController,
itemCount: 100,
itemBuilder: (context, index) {
return Text('This is it.');
},
),
),
],
),
);
}
Try it in your IDE.
EDIT:
Here is the problem in your code, you need to decrease/increase the current offset of the scroll controller by subtracting/adding 200 from the scrollController.position. You are getting it moved for the first time because at that time offset is not at 200 and for the second time it is there at 200. That is why it is not moving which is obviously no error.

Just use a scrollController, attach it to your ListView builder,
then on your Button's onPress/onTap method, call _scrolController.animateTo(someOffset)
Copy the code below and run into your project. I have customized it based on your needs.
import 'package:flutter/material.dart';
class TestView extends StatefulWidget {
const TestView({Key? key}) : super(key: key);
#override
State<TestView> createState() => _TestViewState();
}
class _TestViewState extends State<TestView> {
late ScrollController _scrollController;
#override
void initState() {
_scrollController = ScrollController();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: Column(
children: [
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
ElevatedButton(
onPressed: () {
_scrollController.animateTo(-500,
duration: const Duration(milliseconds: 500),
curve: Curves.easeInOut);
},
child: const Text("-")),
ElevatedButton(
onPressed: () {
_scrollController.animateTo(500,
duration: const Duration(milliseconds: 500),
curve: Curves.easeInOut);
},
child: const Text("+"),
),
],
),
SizedBox(
height: 200,
child: ListView(
controller: _scrollController,
scrollDirection: Axis.horizontal,
children: List.generate(20, (index) {
return Container(
color: Colors.amber,
height: 100,
width: 100,
margin: const EdgeInsets.only(right: 10),
child: Center(child: Text("$index")),
);
}),
),
)
],
),
);
}
}

Is it possible to implement widgets using list in flutter?

I am creating a Journal mobile application which would work as a medium to view magazines and daily news updates. This is my first flutter project and I am totally new to flutter. So kindly excuse me if I had said something wrong about something or didnt provide enough information.
I used a code from github for the main page of my application and made few changes to accommodate my needs. Now in my code, the home page consists of a side menu bar and this bar consists of 4 buttons, namely Home, My Profile, Premium and FAQ. The GlobalKeys for the side menu bar is called using a list by the name _keys which is of the type GlobalKey. I tried changing the data type of the list _keys to Widget and then called the corresponding Widgets of the classes. But then two errors popped out.
The getter 'currentContext' isn't defined for the class 'Widget'.
The argument type 'Widget' can't be assigned to the parameter type 'GlobalKey<State>'.
Now I would like the list _keys to be of the type Widget in order for me to call upon it's corresponding widgets of Home, My Profile, Premium and FAQ from each of it's classes in order for me to view the corresponding pages. Or if it is not possible, I would love to know an alternative for it to start working.
Following is the code of my application.
import 'dart:math' as math;
import 'package:flutter/scheduler.dart';
import 'package:google_signin_example/google%20sign%20in/logged_in_widget.dart';
import 'package:google_signin_example/main app/lib/ui_3/TravelBean.dart';
import 'package:google_signin_example/main app/lib/ui_3/magazine/screens/home_screen.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/FAQ/faq.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/Newspaper%20and%20Kiddos/lib_kiddos/main.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/Newspaper%20and%20Kiddos/lib_news/main.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/premium/premium.dart';
import 'package:google_signin_example/widget/sign_up_widget.dart';
import 'detail_page.dart';
class HomePage1 extends StatefulWidget {
#override
_HomePage1State createState() => _HomePage1State();
}
class _HomePage1State extends State<HomePage1> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: Container(
child: Row(
children: <Widget>[
LeftWidget(),
Expanded(
child: RightWidget(),
)
],
),
),
);
}
}
class LeftWidget extends StatefulWidget {
#override
_LeftWidgetState createState() => _LeftWidgetState();
}
class _LeftWidgetState extends State<LeftWidget> with TickerProviderStateMixin {
List<String> _list = ["Home", "My profile", "Premium", "FAQ"];
List <Widget> _keys = [
HomePage1(), //These are the widgets from different classes.
LoggedInWidget(),
premium(),
faq(),
/*GlobalKey(), //This was available before I made the changes.
GlobalKey(),
GlobalKey(),
GlobalKey()*/
];
int checkIndex = 0;
Offset checkedPositionOffset = Offset(0, 0);
Offset lastCheckOffset = Offset(0, 0);
Offset animationOffset = Offset(0, 0);
Animation _animation;
AnimationController _animationController;
#override
void initState() {
checkIndex = _list.length - 1;
super.initState();
SchedulerBinding.instance.endOfFrame.then((value) {
calcuteCheckOffset();
addAnimation();
});
}
void calcuteCheckOffset() {
lastCheckOffset = checkedPositionOffset;
RenderBox renderBox = _keys[checkIndex].currentContext.findRenderObject(); //This is where the first error occurs.
Offset widgetOffset = renderBox.localToGlobal(Offset(0, 0));
Size widgetSise = renderBox.size;
checkedPositionOffset = Offset(widgetOffset.dx + widgetSise.width,
widgetOffset.dy + widgetSise.height);
}
#override
Widget build(BuildContext context) {
return Container(
child: Stack(
children: <Widget>[
Container(
width: 50,
decoration: BoxDecoration(
color: Color(0xff000000),
borderRadius: BorderRadius.circular(30),
),
child: Column(
children: _buildList(),
),
),
Positioned(
top: animationOffset.dy,
left: animationOffset.dx,
child: CustomPaint(
painter: CheckPointPainter(Offset(10, 0)),
),
)
],
),
);
}
List<Widget> _buildList() {
List<Widget> _widget_list = [];
_widget_list.add(Padding(
padding: EdgeInsets.only(
top: 50,
),
child: Icon(
Icons.settings,
color: Colors.white,
size: 30,
),
));
for (int i = 0; i < _list.length; i++) {
_widget_list.add(Expanded(
child: GestureDetector(
onTap: () {
indexChecked(i);
},
child: VerticalText(
_list[i],
_keys[i], //This is where the second error occurs.
checkIndex == i &&
(_animationController != null &&
_animationController.isCompleted))),
));
}
_widget_list.add(Padding(
padding: EdgeInsets.only(
top: 50,
bottom: 50,
),
child: Image(image: AssetImage('assets/images/Voix.png')),
));
return _widget_list;
}
void indexChecked(int i) {
if (checkIndex == i) return;
setState(() {
checkIndex = i;
calcuteCheckOffset();
addAnimation();
});
}
void addAnimation() {
_animationController =
AnimationController(duration: Duration(milliseconds: 300), vsync: this)
..addListener(() {
setState(() {
animationOffset =
Offset(checkedPositionOffset.dx, _animation.value);
});
});
_animation = Tween(begin: lastCheckOffset.dy, end: checkedPositionOffset.dy)
.animate(CurvedAnimation(
parent: _animationController, curve: Curves.easeInOutBack));
_animationController.forward();
}
}
class CheckPointPainter extends CustomPainter {
double pointRadius = 5;
double radius = 30;
Offset offset;
CheckPointPainter(this.offset);
#override
void paint(Canvas canvas, Size size) {
Paint paint = Paint()..style = PaintingStyle.fill;
double startAngle = -math.pi / 2;
double sweepAngle = math.pi;
paint.color = Color(0xff000000);
canvas.drawArc(
Rect.fromCircle(center: Offset(offset.dx, offset.dy), radius: radius),
startAngle,
sweepAngle,
false,
paint);
paint.color = Color(0xffffffff);
canvas.drawCircle(
Offset(offset.dx - pointRadius / 2, offset.dy - pointRadius / 2),
pointRadius,
paint);
}
#override
bool shouldRepaint(CustomPainter oldDelegate) {
return true;
}
}
class VerticalText extends StatelessWidget {
String name;
bool checked;
GlobalKey globalKey;
VerticalText(this.name, this.globalKey, this.checked);
#override
Widget build(BuildContext context) {
return RotatedBox(
key: globalKey,
quarterTurns: 3,
child: Text(
name,
style: TextStyle(
color: checked ? Color(0xffffffff) : Colors.grey,
fontSize: 16,
),
),
);
}
}
class RightWidget extends StatefulWidget {
#override
_RightWidgetState createState() => _RightWidgetState();
}
class _RightWidgetState extends State<RightWidget>
with TickerProviderStateMixin {
TabController _tabController;
#override
void initState() {
super.initState();
_tabController = TabController(vsync: this, length: 5);
}
#override
Widget build(BuildContext context) {
return Container(
margin: EdgeInsets.only(
left: 15,
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Padding(
padding: EdgeInsets.only(top: 50, left: 20),
child: Text(
"Voix Home",
style: TextStyle(
color: Colors.black,
fontSize: 25,
),
),
),
Padding(
padding: const EdgeInsets.only(top: 15, left: 10),
child: SizedBox(
height: 30,
child: TabBar(
isScrollable: true,
unselectedLabelColor: Colors.black,
labelColor: Color(0xffffffff),
controller: _tabController,
indicator: BoxDecoration(
color: Color(0xff9e9e9e),
borderRadius: BorderRadius.only(
topRight: Radius.circular(20),
bottomLeft: Radius.circular(20),
),
),
tabs: <Widget>[
Tab(
text: "Flash",
),
Tab(
text: "Magazine",
),
Tab(
text: "Newspaper",
),
Tab(
text: "Kiddos",
),
Tab(
text: "Editorial",
),
],
),
),
),
Expanded(
child: TabBarView(
controller: _tabController,
children: <Widget>[
TravelWidget(),
HomeScreen(),
News(),
Kiddos(),
RightBody(),
// RightBody(),
],
),
)
],
),
);
}
}
class RightBody extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
margin: EdgeInsets.only(
left: 15,
),
color: Colors.white,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Padding(
padding: EdgeInsets.only(
top: 20,
),
child: Text(
"Flash!",
style: TextStyle(
color: Colors.black,
fontSize: 20,
),
),
),
Expanded(
child: ListView(
scrollDirection: Axis.horizontal,
children: <Widget>[
Container(
width: 220,
margin: EdgeInsets.symmetric(
horizontal: 10,
vertical: 10,
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(40),
image: new DecorationImage(
image: new AssetImage('assets/images/bottom1.jpg'),
fit: BoxFit.cover,
),
boxShadow: [
BoxShadow(
spreadRadius: 5,
blurRadius: 5,
offset: Offset(1, 2),
color: Color(0x33757575),
),
],
),
),
Container(
width: 220,
margin: EdgeInsets.symmetric(
horizontal: 10,
vertical: 10,
),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(40),
boxShadow: [
BoxShadow(
spreadRadius: 5,
blurRadius: 5,
offset: Offset(1, 2),
color: Color(0x33757575),
),
],
),
),
],
),
),
],
),
);
}
}
class TravelWidget extends StatelessWidget {
List<TravelBean> _list = TravelBean.generateTravelBean();
#override
Widget build(BuildContext context) {
return PageView.builder(
controller: PageController(viewportFraction: 0.9),
itemBuilder: (context, index) {
var bean = _list[index];
return GestureDetector(
onTap: () {
Navigator.of(context).push(MaterialPageRoute(builder: (context) {
return DetailPage(bean);
}));
},
child: Hero(
tag: bean.url,
child: Stack(
children: <Widget>[
Padding(
padding: const EdgeInsets.only(bottom: 30, right: 10),
child: ClipRRect(
borderRadius: BorderRadius.circular(5),
child: Image.asset(
bean.url,
width: MediaQuery.of(context).size.width,
fit: BoxFit.cover,
),
),
),
Positioned(
bottom: 80,
left: 15,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Material(
color: Colors.transparent,
child: Text(
bean.location,
style: TextStyle(
color: Colors.black54,
fontSize: 15,
),
),
),
Material(
color: Colors.transparent,
child: Text(
bean.name,
style: TextStyle(
color: Colors.black,
fontSize: 20,
),
),
),
],
),
),
Positioned(
bottom: 0,
right: 30,
child: Container(
width: 60,
height: 60,
decoration: BoxDecoration(
color: Colors.black,
borderRadius: BorderRadius.circular(30),
),
child: Icon(
Icons.arrow_forward,
color: Colors.white,
size: 30,
),
),
)
],
),
),
);
},
itemCount: _list.length,
);
}
}
At the beginning, when I leave the list _keys to be of the type GlobalKey and don't comment out the following 4 GlobalKeys I get the output but the side menu bar won't work.
This is my application with GlobalKeys in place of those Widgets
I want those corresponding pages to display when clicked on. But that render object just switches between the options and the same page is displayed.
So kindly help me out.
PS : As said earlier I'm new to flutter, so kindly don't mistake me if I had something wrong.

I suggest you check about flutter state management, especially Mobx with Provider, it will be kind easier for you.

Flutter : How to prevent rebuild of whole Reorderable Listview?

Currently I'm using flutter package 'Reorderables' to show a reorderable listview which contains several images.These images can be deleted from listview through a button , everything works fine. But the listview rebuild everytime when I delete an image. I'm using a class called 'ReorderableListviewManager' with ChangeNotifier to update images and Provider.of<ReorderableListviewManager>(context) to get latest images . The problem now is that using Provider.of<ReorderableListviewManager>(context) makes build() called everytime I delete an image , so the listview rebuid. I koow I
can use consumer to only rebuild part of widget tree, but it seems like that there's no place to put consumer in children of this Listview. Is there a way to rebuild only image but not whole ReorderableListview ? Thanks very much!
Below is my code:
class NotePicturesEditScreen extends StatefulWidget {
final List<Page> notePictures;
final NotePicturesEditBloc bloc;
NotePicturesEditScreen({#required this.notePictures, #required this.bloc});
static Widget create(BuildContext context, List<Page> notePictures) {
return Provider<NotePicturesEditBloc>(
create: (context) => NotePicturesEditBloc(),
child: Consumer<NotePicturesEditBloc>(
builder: (context, bloc, _) =>
ChangeNotifierProvider<ReorderableListviewManager>(
create: (context) => ReorderableListviewManager(),
child: NotePicturesEditScreen(
bloc: bloc,
notePictures: notePictures,
),
)),
dispose: (context, bloc) => bloc.dispose(),
);
}
#override
_NotePicturesEditScreenState createState() => _NotePicturesEditScreenState();
}
class _NotePicturesEditScreenState extends State<NotePicturesEditScreen> {
PreloadPageController _pageController;
ScrollController _reorderableScrollController;
List<Page> notePicturesCopy;
int longPressIndex;
List<double> smallImagesWidth;
double scrollOffset = 0;
_reorderableScrollListener() {
scrollOffset = _reorderableScrollController.offset;
}
#override
void initState() {
Provider.of<ReorderableListviewManager>(context, listen: false)
.notePictures = widget.notePictures;
notePicturesCopy = widget.notePictures;
_reorderableScrollController = ScrollController();
_pageController = PreloadPageController();
_reorderableScrollController.addListener(_reorderableScrollListener);
Provider.of<ReorderableListviewManager>(context, listen: false)
.getSmallImagesWidth(notePicturesCopy, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
super.initState();
}
#override
void dispose() {
_pageController.dispose();
_reorderableScrollController.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
ReorderableListviewManager reorderableManager =
Provider.of<ReorderableListviewManager>(context, listen: false);
return SafeArea(
child: Scaffold(
appBar: AppBar(
backgroundColor: Colors.white,
shape: Border(bottom: BorderSide(color: Colors.black12)),
iconTheme: IconThemeData(color: Colors.black87),
elevation: 0,
automaticallyImplyLeading: false,
titleSpacing: 0,
centerTitle: true,
title: Row(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Container(
child: IconButton(
padding: EdgeInsets.only(left: 20, right: 12),
onPressed: () => Navigator.of(context).pop(),
icon: Icon(Icons.close),
),
),
Text('編輯',
style: TextStyle(color: Colors.black87, fontSize: 18))
],
),
actions: <Widget>[
FlatButton(
onPressed: () {},
child: Text(
'下一步',
),
)
],
),
backgroundColor: Color(0xffeeeeee),
body: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Spacer(),
StreamBuilder<List<Page>>(
initialData: widget.notePictures,
stream: widget.bloc.notePicturesStream,
builder: (context, snapshot) {
notePicturesCopy = snapshot.data;
return Container(
margin: EdgeInsets.symmetric(horizontal: 20),
height: MediaQuery.of(context).size.height * 0.65,
child: PreloadPageView.builder(
preloadPagesCount: snapshot.data.length,
controller: _pageController,
itemCount: snapshot.data.length,
onPageChanged: (index) {
reorderableManager.updateCurrentIndex(index);
reorderableManager.scrollToCenter(
smallImagesWidth,
index,
scrollOffset,
_reorderableScrollController,
context);
},
itemBuilder: (context, index) {
return Container(
child: Image.memory(
File.fromUri(
snapshot.data[index].polygon.isNotEmpty
? snapshot.data[index]
.documentPreviewImageFileUri
: snapshot.data[index]
.originalPreviewImageFileUri)
.readAsBytesSync(),
gaplessPlayback: true,
alignment: Alignment.center,
),
);
}),
);
},
),
Spacer(),
Container(
height: MediaQuery.of(context).size.height * 0.1,
margin: EdgeInsets.symmetric(horizontal: 20),
child: SingleChildScrollView(
scrollDirection: Axis.horizontal,
child: ReorderableRow(
scrollController: _reorderableScrollController,
buildDraggableFeedback: (context, constraints, __) =>
Container(
width: constraints.maxWidth,
height: constraints.maxHeight,
child: Image.memory(File.fromUri(
notePicturesCopy[longPressIndex]
.polygon
.isNotEmpty
? notePicturesCopy[longPressIndex]
.documentPreviewImageFileUri
: notePicturesCopy[longPressIndex]
.originalPreviewImageFileUri)
.readAsBytesSync()),
),
onReorder: (oldIndex, newIndex) async {
List<Page> result = await widget.bloc.reorderPictures(
oldIndex,
newIndex,
reorderableManager.notePictures);
_pageController.jumpToPage(newIndex);
reorderableManager.updateNotePictures(result);
reorderableManager
.getSmallImagesWidth(result, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
},
footer: Container(
width: 32,
height: 32,
margin: EdgeInsets.only(left: 16),
child: SizedBox(
child: FloatingActionButton(
backgroundColor: Colors.white,
elevation: 1,
disabledElevation: 0,
highlightElevation: 1,
child: Icon(Icons.add, color: Colors.blueAccent),
onPressed: notePicturesCopy.length >= 20
? () {
Scaffold.of(context)
.showSnackBar(SnackBar(
content: Text('筆記上限為20頁 !'),
));
}
: () async {
List<Page> notePictures =
await widget.bloc.addPicture(
reorderableManager.notePictures);
List<double> imagesWidth =
await reorderableManager
.getSmallImagesWidth(
notePictures, context);
smallImagesWidth = imagesWidth;
reorderableManager.updateCurrentIndex(
notePictures.length - 1);
reorderableManager
.updateNotePictures(notePictures);
_pageController
.jumpToPage(notePictures.length - 1);
},
),
),
),
children: Provider.of<ReorderableListviewManager>(
context)
.notePictures
.asMap()
.map((index, page) {
return MapEntry(
index,
Consumer<ReorderableListviewManager>(
key: ValueKey('value$index'),
builder: (context, manager, _) =>
GestureDetector(
onTapDown: (_) {
longPressIndex = index;
},
onTap: () {
reorderableManager.scrollToCenter(
smallImagesWidth,
index,
scrollOffset,
_reorderableScrollController,
context);
_pageController.jumpToPage(index);
},
child: Container(
margin: EdgeInsets.only(
left: index == 0 ? 0 : 12),
decoration: BoxDecoration(
border: Border.all(
width: 1.5,
color: index ==
manager
.getCurrentIndex
? Colors.blueAccent
: Colors.transparent)),
child: index + 1 <=
manager.notePictures.length
? Image.memory(
File.fromUri(manager
.notePictures[
index]
.polygon
.isNotEmpty
? manager
.notePictures[
index]
.documentPreviewImageFileUri
: manager
.notePictures[
index]
.originalPreviewImageFileUri)
.readAsBytesSync(),
gaplessPlayback: true,
)
: null),
),
));
})
.values
.toList()),
)),
Spacer(),
Container(
decoration: BoxDecoration(
color: Colors.white,
border: Border(top: BorderSide(color: Colors.black12))),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
FlatButton(
onPressed: () async => await widget.bloc
.cropNotePicture(reorderableManager.notePictures,
_pageController.page.round())
.then((notePictures) {
reorderableManager.updateNotePictures(notePictures);
reorderableManager
.getSmallImagesWidth(notePictures, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
}),
child: Column(
children: <Widget>[
Icon(
Icons.crop,
color: Colors.blueAccent,
),
Container(
margin: EdgeInsets.only(top: 1),
child: Text(
'裁切',
style: TextStyle(color: Colors.blueAccent),
),
)
],
),
),
FlatButton(
onPressed: () {
int deleteIndex = _pageController.page.round();
widget.bloc
.deletePicture(
reorderableManager.notePictures, deleteIndex)
.then((notePictures) {
if (deleteIndex == notePictures.length) {
reorderableManager
.updateCurrentIndex(notePictures.length - 1);
}
reorderableManager.updateNotePictures(notePictures);
reorderableManager
.getSmallImagesWidth(notePictures, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
if (reorderableManager.notePictures.length == 0) {
Navigator.pop(context);
}
});
},
child: Column(
children: <Widget>[
Icon(
Icons.delete_outline,
color: Colors.blueAccent,
),
Container(
margin: EdgeInsets.only(top: 1),
child: Text(
'刪除',
style: TextStyle(color: Colors.blueAccent),
),
),
],
),
)
],
),
)
],
)),
);
}
}

You can't prevent a rebuild on your ReorderableListView widget because it will be rebuild every time there's an update on the Provider. What you can do here is to keep track the current index of all visible ListView items. When new data should be displayed coming from the Provider, you can retain the current indices of previous ListView items, and add the newly added items at the end of the list, or wherever you like.

getting "Connection closed before full header was received While loading image from network

I have seen many same questions but they don't have answers yet, so I decided to put it again.
I am using rest API to load data in Gridview.count with ScrollController which is generally working fine but many times some images are not loading on the frame and i got this error:-
"Connection closed before full header was received, uri =IMAGE URL"
Here is my code
class CreateHome extends StatefulWidget {
_AppState state;
BuildContext context;
CreateHome(this.state, this.context);
#override
State<StatefulWidget> createState() {
// TODO: implement createState
return new CreateHomeState(state, context);
}
}
class CreateHomeState extends State<CreateHome> {
_AppState state;
BuildContext context;
int _selectBuilder = 0;
List<ProductModel> productList = new List();
CreateHomeState(this.state, this.context);
ScrollController _controller;
String lasthit = "";
FutureBuilder<List<ProductModel>> _getFutureBuilder(int pos) {
switch (pos) {
case 0:
return new FutureBuilder(
future: Api.getProductList(context, '0'),
builder: (context, snapshot) {
if (snapshot.hasData) {
productList.addAll(snapshot.data);
return GridList(productList);
} else if (snapshot.hasError) {
Toast.show(snapshot.error, context,
duration: 3, backgroundColor: Colors.deepOrange);
}
return RoundProgress();
},
);
case 1:
return new FutureBuilder(
future: Api.getProductList(
context, productList[productList.length - 1].product_id),
builder: (context, snapshot) {
lasthit = productList[productList.length - 1].product_id;
if (snapshot.hasData) {
productList.addAll(snapshot.data);
//productList = productList.sublist(productList.length-7, productList.length-1);
var distinctIds = productList.toSet().toList();
return GridList(distinctIds);
} else if (snapshot.hasError) {
Toast.show(snapshot.error, context,
duration: 3, backgroundColor: Colors.deepOrange);
}
return RoundProgress();
},
);
}
}
#override
void initState() {
print('initstatecalled');
_controller = ScrollController();
_controller.addListener(_scrollListener);
super.initState();
}
_scrollListener() {
if (_controller.offset >= _controller.position.maxScrollExtent &&
!_controller.position.outOfRange) {
print(productList.length.toString());
String currentHit = productList[productList.length - 1].product_id;
if (currentHit != lasthit) {
setState(() {
_selectBuilder = 1;
});
}
}
}
#override
Widget build(BuildContext context) {
return SingleChildScrollView(
controller: _controller,
child: Container(
color: Colors.black12,
//=========Main Container For Scrollview==============//
child: Padding(
padding: const EdgeInsets.fromLTRB(0, 15, 0, 0),
child: Column(
children: <Widget>[
Container(
width: double.infinity,
//================Container for Categories==================//
color: Colors.white,
child: Container(
height: 130,
child: FutureBuilder<List<CategoryModel>>(
future: Api.getDataCategories(context),
builder: (context, snapshot) {
if (snapshot.hasData) {
List<CategoryModel> categoryListing = snapshot.data;
return ListView.builder(
scrollDirection: Axis.horizontal,
shrinkWrap: true,
itemCount: categoryListing.length,
itemBuilder: (BuildContext context, int index) {
return createList(
state,
categoryListing[index].url,
categoryListing[index].name,
1,
categoryListing[index].id);
},
);
} else if (snapshot.hasError) {
Toast.show("Error", context,
duration: 3,
gravity: Toast.BOTTOM,
backgroundColor: Colors.deepOrange);
}
return RoundProgress();
},
),
),
),
Padding(
padding: const EdgeInsets.fromLTRB(0, 20, 0, 20),
child: Container(
color: Colors.white,
child: Padding(
padding: const EdgeInsets.fromLTRB(0, 10, 0, 10),
child: SizedBox(
child: FutureBuilder<List<String>>(
future: Api.getBanners(context, "front"),
builder: (context, snapshot) {
if (snapshot.hasData) {
List<String> images = snapshot.data;
return CarouselWithIndicator(images);
} else if (snapshot.hasError) {
Toast.show("Error", context,
duration: 3,
gravity: Toast.BOTTOM,
backgroundColor: Colors.deepOrange);
}
return RoundProgress();
},
),
),
),
),
),
Container(
color: Colors.white, child: _getFutureBuilder(_selectBuilder))
],
),
),
),
);
}
}
This is my code for making GridView
class GridList extends StatelessWidget {
List<ProductModel> list;
GridList(this.list);
#override
Widget build(BuildContext context) {
print('length from grid..'+list.length.toString());
IconData icon;
Color color;
String price;
bool boolean;
return Padding(
padding: const EdgeInsets.fromLTRB(10, 10, 10, 20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Padding(
padding: const EdgeInsets.fromLTRB(0, 10, 0, 10),
child: Text(
'Popular Products',
style: TextStyle(
fontSize: 16,
fontFamily: 'SFProRegular',
color: Colors.black),
),
),
Padding(
padding: const EdgeInsets.fromLTRB(0, 10, 0, 0),
child: GridView.count(
shrinkWrap: true,
primary: false,
childAspectRatio: 0.6,
//(itemWidth / itemHeight),
crossAxisCount: 2,
children: List.generate(list.length, (index) {
if (list[index].wishlist == "1") {
icon = Icons.favorite;
color = Colors.red;
} else {
icon = Icons.favorite_border;
color = Colors.black38;
}
if (list[index].discounted_price != "0") {
price = "Rs " + list[index].discounted_price;
boolean = true;
} else {
price = "Rs " + list[index].price;
boolean = false;
}
return Wrap(
children: <Widget>[
Card(
elevation: 5,
child: Container(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
new Container(
constraints: new BoxConstraints.expand(
height: 150.0,
),
padding:
new EdgeInsets.only(top: 8.0, right: 8.0),
decoration: new BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(4),
topRight: Radius.circular(4)),
image: new DecorationImage(
image:
new NetworkImage(list[index].image_url),
fit: BoxFit.cover,
),
),
child: new Stack(
children: <Widget>[
new Positioned(
right: 0.0,
top: 0.0,
child: Material(
borderRadius: BorderRadius.all(
Radius.circular(50)),
child: Padding(
padding: const EdgeInsets.all(6.0),
child: Center(
child: new Icon(
icon,
color: color,
size: 16,
),
),
),
),
),
],
)),
Padding(
padding:
const EdgeInsets.fromLTRB(5.0, 10, 0, 10),
child: Text(
list[index].product_name,
style: TextStyle(
fontSize: 16,
fontFamily: 'SFProRegular',
color: Colors.black),
),
),
Padding(
padding: const EdgeInsets.fromLTRB(5.0, 0, 0, 10),
child: Row(
children: <Widget>[
Icon(
Icons.person,
size: 23,
color: Colors.black38,
),
Padding(
padding:
const EdgeInsets.fromLTRB(5.0, 0, 0, 0),
child: Text(
list[index].designer,
style: TextStyle(
fontSize: 14,
fontFamily: 'SFProRegular',
color: Colors.black38,
decoration: TextDecoration.underline,
),
),
),
],
),
),
Padding(
padding: const EdgeInsets.fromLTRB(5.0, 2, 0, 10),
child: Row(
children: <Widget>[
Text(
price,
style: TextStyle(
fontSize: 13,
fontFamily: 'SFProRegular',
color: Colors.green),
),
Padding(
padding:
const EdgeInsets.fromLTRB(10, 0, 0, 0),
child: Visibility(
visible: boolean,
maintainSize: true,
maintainAnimation: true,
maintainState: true,
child: Text(
"Rs " + list[index].price,
style: TextStyle(
fontSize: 13,
fontFamily: 'SFProRegular',
color: Colors.grey,
decoration:
TextDecoration.lineThrough),
),
),
),
],
),
),
Padding(
padding: const EdgeInsets.fromLTRB(5.0, 0, 0, 5),
child: Visibility(
maintainSize: true,
maintainAnimation: true,
maintainState: true,
visible: boolean,
child: Text(
list[index].discount + '% OFF',
style: TextStyle(
fontSize: 13,
fontFamily: 'SFProRegular',
color: Colors.deepOrange),
),
),
),
],
),
),
),
],
);
}),
crossAxisSpacing: 3.0,
mainAxisSpacing: 5.0,
),
),
],
),
);
}
}

this issue will be solved by
Flutter Clean
run

Keyboard getting dismissed on click of TextField

I have a TextField on the tap of which keyboard opens and dismiss immediately. This is my code for TextField:
class DataItem extends StatefulWidget {
Data data;
List<Menu> menuList;
int quantity;
String price;
String title;
var id;
DataItem(
{this.data,
this.menuList,
this.id,
this.quantity,
this.price,
this.title});
#override
_DataItemState createState() => _DataItemState();
}
class _DataItemState extends State<DataItem> {
String selectedType = 'Select Type';
String comments = 'No';
#override
Widget build(BuildContext context) {
return Dismissible(
key: UniqueKey(),
background: Container(
color: Theme.of(context).errorColor,
child: Icon(
Icons.delete,
color: Colors.white,
size: 40,
),
alignment: Alignment.centerRight,
padding: EdgeInsets.only(right: 20),
margin: EdgeInsets.symmetric(
horizontal: 15,
vertical: 4,
),
),
direction: DismissDirection.endToStart,
confirmDismiss: (direction) {
return showDialog(
context: context,
builder: (ctx) => AlertDialog(
title: Text('Are you sure?'),
content: Text('Do you want to remove?'),
actions: <Widget>[
FlatButton(
child: Text('No'),
onPressed: () {
Navigator.of(ctx).pop(false);
},
),
FlatButton(
child: Text('Yes'),
onPressed: () {
Navigator.of(ctx).pop(true);
},
)
],
),
);
},
onDismissed: (direction) {
//Delete Functionality
},
child: Card(
margin: EdgeInsets.symmetric(
horizontal: 15,
vertical: 4,
),
child: Padding(
padding: EdgeInsets.all(8),
child: Column(
children: <Widget>[
ListTile(
leading: CircleAvatar(
backgroundColor:Colors.purple,
child: Padding(
padding: EdgeInsets.all(5),
child: FittedBox(
child: Text(
widget.price,
style: TextStyle(color: Colors.white),
),
),
),
),
title: Text(widget.title),
subtitle: Text(
'Total: 0',
),
trailing: Text(widget.quantity.toString() + ' x'),
),
Padding(
padding: const EdgeInsets.only(
left: 15, right: 5, top: 5, bottom: 5),
child: Container(
width: double.infinity,
decoration: (BoxDecoration(
borderRadius: BorderRadius.circular(7),
border: Border.all(color:Colors.red))),
child: DropdownButton<String>(
items:
<String>['Type1 ', 'Type2'].map((String value) {
return new DropdownMenuItem<String>(
value: value,
child: new Text(
value,
style: TextStyle(color: Colors.black),
),
);
}).toList(),
hint: Padding(
padding: const EdgeInsets.only(left: 16),
child: Text(selectedType),
),
onChanged: (String val) {
setState(() {
selectedType = val;
selectedType);
});
},
),
),
),
Padding(
padding: const EdgeInsets.only(
left: 32, right: 5, top: 10, bottom: 5),
child: GestureDetector(
onTap: () {
var focusNode = new FocusNode();
// var textField = new TextField(focusNode: focusNode);
FocusScope.of(context).requestFocus(focusNode);
},
child: TextField(
decoration:
new InputDecoration.collapsed(hintText: 'Add Comments'),
),
)
],
),
),
),
);
}
This is the code of the DataItem class. On tap of TextField the keyboard opens and dismiss immediately. Please Help. I have tried using GestureDetector, request focus and onChanged as well but nothing works.

You should put your focus node outside your build method. Tested example added.
var focusNode = new FocusNode(); // This should be here and not inside the build method
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding:
const EdgeInsets.only(left: 32, right: 5, top: 10, bottom: 5),
child: GestureDetector(
onTap: () {
FocusScope.of(context).requestFocus(focusNode);
},
child: TextField(
decoration:
InputDecoration.collapsed(hintText: 'Add Comments'),
),
),
),
],
),
),
);
DartPad Example

I have resolved this issue using TextFormField instead of TextField.