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")),
);
}),
),
)
],
),
);
}
}

Unexpected Line between Containers Flutter

Many Times in flutter I Found a Line between two Containers in flutter.
Code example
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
const MyHomePage({
Key? key,
required this.title,
}) : super(key: key);
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
title: Text(widget.title),
),
body: SingleChildScrollView(
child: Column(
children: [
Container(
color: Colors.red,
width: double.infinity,
child: Column(
children: [
Container(
height: 150,
child: const Center(
child: Text('cdccd'),
),
),
Container(
height: 20,
color: Colors.red,
),
buildSeperator()
],
),
),
Container(
height: 300,
width: double.infinity,
child: Text('cdcdcd'),
),
],
),
),
);
}
///Build Seperator
Widget buildSeperator() {
return Stack(
children: [
Container(
height: 24,
color: Colors.red,
),
Container(
decoration: const BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(50),
topRight: Radius.circular(50),
),
color: Colors.white,
),
height: 24,
width: double.infinity,
),
],
);
}
}
Reference Image:
If It's a Flutter Issue: Flutter Team Request you to Resolve it.

Work Around but not final Solution,
Add Another Container Above the Container with a border with a higher height.
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
elevation: 0,
backgroundColor: Color(0xFF842247),
title: Text(widget.title),
),
body: SingleChildScrollView(
child: Column(
children: [
Container(
color: const Color(0xFF842247),
height: 56,
),
Container(
color: const Color(0xFF842247),
width: double.infinity,
child: Column(
children: [
Container(
height: 24,
child: const Center(
child: Text('cdccd'),
),
),
buildSeperator()
],
),
),
Container(
height: 300,
// width: double.infinity,
child: Text('cdcdcd'),
),
],
),
),
);
}
///Build Seperator
Widget buildSeperator() {
return Stack(
clipBehavior: Clip.none,
children: [
Container(
height: 24,
color: const Color(0xFF842247),
),
Container(
decoration: const BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(50),
topRight: Radius.circular(50),
),
color: Colors.white,
),
height: 24,
width: double.infinity,
),
],
);
}
}

Why is my widget not taking up all the space in the bottomNavigationBar?

I'm new to Flutter and I just start coding the UI of a chat app so I figure out that my widget doesn't take all the space of the bottom navigation bar like the photo shows : shows
This is my camera widget code :
import 'package:flutter/material.dart';
import 'dart:io';
import 'package:image_picker/image_picker.dart';
class Camera extends StatefulWidget {
#override
_CameraState createState() => _CameraState();
}
class _CameraState extends State<Camera> {
File _image;
final imagePicker = ImagePicker();
Future getImage() async {
final image = await imagePicker.getImage(source: ImageSource.camera);
setState(() {
_image = File(image.path);
});
}
#override
Widget build(BuildContext context) {
return SizedBox(
height: 100,
child: Container(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Container(
width: 80.0,
height: 80.0,
child: FloatingActionButton(
backgroundColor: Colors.white,
onPressed: getImage,
child: Icon(
Icons.camera_alt_rounded,
color: Colors.lightBlue[600],
size: 35.0,
),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(20.0))),
),
),
],
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(20),
color: Colors.lightBlue[50],
boxShadow: [
BoxShadow(color: Colors.grey[100], spreadRadius: 3),
],
),
height: 50,
),
);
}
}
and this is the chat screen code :
import 'dart:io';
import 'package:mychat/services/auth.dart';
import 'package:flutter/material.dart';
import 'package:mychat/chat/chat.dart';
import 'package:mychat/widgets/Med_form.dart';
import 'package:mychat/widgets/bottomButtons.dart';
import 'package:mychat/widgets/camera.dart';
import 'package:mychat/widgets/incrementAndDecrement.dart';
import 'package:mychat/widgets/yesOrno.dart';
class ChatScreen extends StatefulWidget {
#override
_ChatScreenState createState() => _ChatScreenState();
}
class _ChatScreenState extends State<ChatScreen> {
File _image;
final AuthService _auth = AuthService();
List<String> messages = [
'fizikefgzerpgr',
'fioezhfejzifojef',
'fvfzerfergnyolnkyokjy',
'rgop^l^lmf^prlgprgprp'
];
List<String> responses = [
'fizikefgzerpgr',
'fezfzefzefezff',
'ofpkoepzkfopkzef',
'fjeziofjiozejfozejf'
];
//final AuthService _auth = AuthService();
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Directionality(
textDirection: TextDirection.rtl,
child: Scaffold(
appBar: PreferredSize(
preferredSize: Size.fromHeight(90),
child: AppBar(
title: new Text(
"لاباس ⸮",
style: TextStyle(
color: Colors.black,
fontSize: 30.0,
fontWeight: FontWeight.bold),
),
centerTitle: true,
flexibleSpace: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.topRight,
end: Alignment.bottomRight,
colors: [Colors.blueGrey[300], Colors.grey[50]])),
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.arrow_forward_ios_outlined,
color: Colors.black,
),
onPressed: () async {
await _auth.signOut();
})
],
elevation: 0.0,
),
),
body: Chat_page(messages: messages, responses: responses),
bottomNavigationBar: Camera(),
),
));
}
}
and this is the code of the messages:
import 'package:bubble/bubble.dart';
import 'package:flutter/material.dart';
class Chat_page extends StatefulWidget {
List<String> messages;
List<String> responses;
Chat_page({this.messages, this.responses});
#override
_Chat_pageState createState() => _Chat_pageState();
}
class _Chat_pageState extends State<Chat_page> {
String message;
int data;
#override
Widget build(BuildContext context) {
return Container(
child: Column(
children: [
/* Container(
padding: EdgeInsets.only(top: 15, bottom: 10),
child: Text(
"Today, 10",
style: TextStyle(fontSize: 20, color: Colors.white),
),
), */
Flexible(
child: widget.messages.length > 0
? ListView.builder(
reverse: true,
shrinkWrap: true,
itemCount: widget.messages.length,
itemBuilder: (context, index) => Column(
children: [
widget.messages.length > 0
? chat(widget.messages[index].toString(), 1)
: Container(),
widget.responses.length > 0
? chat(widget.responses[index].toString(), 0)
: Container(),
],
))
: Container(),
),
SizedBox(
height: 20,
),
SizedBox(
height: 15.0,
)
],
));
}
}
Widget chat(String message, int data) {
return Container(
padding: EdgeInsets.only(left: 20, right: 20),
child: Row(
mainAxisAlignment:
data == 1 ? MainAxisAlignment.end : MainAxisAlignment.start,
children: [
data == 0
? Container(
height: 60,
width: 60,
child: CircleAvatar(
child: Icon(Icons.account_circle),
),
)
: Container(),
Padding(
padding: EdgeInsets.all(10.0),
child: Bubble(
radius: Radius.circular(15.0),
color: data == 0 ? Color(0xFFf7ede2) : Color(0xFFf7ede2),
elevation: 0.0,
child: Padding(
padding: EdgeInsets.all(2.0),
child: Row(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
SizedBox(
width: 10.0,
),
Flexible(
child: Container(
constraints: BoxConstraints(maxWidth: 200),
child: Text(
message,
style: TextStyle(
color: Colors.black, fontWeight: FontWeight.bold),
),
))
],
),
)),
),
data == 1
? Container(
height: 60,
width: 60,
child: CircleAvatar(
child: Icon(Icons.account_circle),
),
)
: Container(),
],
),
);
}
so how can I fix this the make my camera widget take the full space

try to change
SizedBox(
height: 100,
child: Container(
to
Container(
height: 100,
width:double.infinty,

Change color of cupertino scrollbar in flutter

I need to change color of cupertino scrollbar, but I can't do that via normal constructor. Is there any way to make scrollbar white?
CupertinoScrollbar(
thickness: 5,
controller: scrollController,
thicknessWhileDragging: 8,
//color not exist
)

The CupertinoScrollBar is hardcoded so on iOS you can't change the color, but you can use highlightColor for the ThemeData. The Color will then displayed on Android only.
MaterialApp(
debugShowCheckedModeBanner: false,
theme: ThemeData(
//main color
primaryColor: const Color(0xffFFC600),
//main font
fontFamily: 'Roboto-Medium',
//swatch stretching
primarySwatch: goldenThemeColor,
visualDensity: VisualDensity.adaptivePlatformDensity,
splashColor: const Color(0xffFFC600),
//color for scrollbar
highlightColor: Color(0xffffc600)
),
import 'package:flutter/material.dart';
class LandingPage extends StatefulWidget {
LandingPage({Key key}) : super(key: key);
#override
State<StatefulWidget> createState() {
return _LandingPageState();
}
}
class _LandingPageState extends State<LandingPage> {
ScrollController _controller;
double _offset = 0;
#override
void initState() {
_controller = ScrollController();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: Stack(
children: [
Container(
child: SingleChildScrollView(
controller: _controller,
child: Column(
children: [
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
color: Colors.black,
),
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
color: Colors.red,
),
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
color: Colors.green,
),
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
color: Colors.blue,
),
],
),
),
),
//Scroll bar
Container(
alignment: Alignment.centerRight,
height: MediaQuery.of(context).size.height,
width: 20.0,
margin: EdgeInsets.only(left: MediaQuery.of(context).size.width - 20.0),
decoration: BoxDecoration(color: Colors.black12),
child: Container(
alignment: Alignment.topCenter,
child: GestureDetector(
child: Container(
height: 40.0,
width: 15.0,
margin:
EdgeInsets.only(left: 5.0, right: 5.0, top: _offset),
decoration: BoxDecoration(
color: Colors.grey, //Change Color here
borderRadius: BorderRadius.all(Radius.circular(3.0))),
),
onVerticalDragUpdate: (dragUpdate) {
_controller.position.moveTo(dragUpdate.globalPosition.dy * 3.5);
setState(() {
if(dragUpdate.globalPosition.dy >= 0) {
_offset = dragUpdate.globalPosition.dy;
}
print("View offset ${_controller.offset} scroll-bar offset ${_offset}");
});
},
),
)
),
],
),
);
}
}

Flutter - Adding Container (widget) in GridView when click a button?

I wanted to add a container widget in the GridView when a button is clicked. I was able to do this with the column widget but could not do it with GridView.
import 'package:flutter/material.dart';
List<Widget> gridChild = [
Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
),
Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
),
Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
),
Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
),
Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
),
];
class Grid extends StatefulWidget {
#override
_GridState createState() => _GridState();
}
class _GridState extends State<Grid> {
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.red,
child: Icon(Icons.add),
onPressed: () {
setState(() {
gridChild.add(Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
));
print(gridChild.length);
});
},
),
body: Container(
child: GridView.count(
crossAxisCount: 2,
children: gridChild,
),
),
);
}
}
What I did was that I added a container in the widget list. The length of the list increases as I click the botton but the container was not added on the screen. It didn't work even though I put the function inside the setState().
I would really appreciate your help.

This works...
class Grid extends StatefulWidget {
#override
_GridState createState() => _GridState();
}
class _GridState extends State<Grid> {
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.red,
child: Icon(Icons.add),
onPressed: () {
setState(() {
gridChild.add(Container(
margin: EdgeInsets.all(8.0),
width: 30.0,
height: 50.0,
color: Colors.green,
));
});
},
),
body: Container(
child: GridView.count(
crossAxisCount: 2,
children: List.generate(gridChild.length, (index) => gridChild[index]),
),
),
);
}
}
Output:

Use GridView.builder in the body. It should fix your problem. I don't really know why, but I know it works. Hopefully someone can update this answer and provide an explanation.
GridView.builder(
itemCount: gridChild.length,
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
),
itemBuilder: (BuildContext context, int index){
return gridChild[index];
},
),

You can do it by calling the setstate method.
while clicking on the button just add a widget to the list and use the setstate after adding to the list. Basically setstate will rebuild the screen.