I'm learning Flutter. I have a ListView and I would like to make the list items clickable. My idea is that when the user clicks on an item, it will be directed to another screen. Each buttom should leads to different screen. I'm having trouble implementing it, I don't know what to use: gesture detector or ontap. What should I do? Should I use ListTile instead of ListView?
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
final title = "ListView List";
return MaterialApp(
title: title,
home: Scaffold(appBar: AppBar(
title: Text(title),
),
body: new ListView(
shrinkWrap: true,
padding: const EdgeInsets.all(20.0),
children: List.generate(choices.length, (index) {
return Center(
child: ChoiceCard(choice: choices[index], item: choices[index]),
);
}
)
)
)
);
}
}
class Choice {
const Choice({this.title, this.icon});
final String title;
final IconData icon;
}
const List<Choice> choices = const <Choice>[
const Choice(title: 'This is a Car', icon: Icons.directions_car),
const Choice(title: 'This is a Bicycle', icon: Icons.directions_bike),
const Choice(title: 'This is a Boat', icon: Icons.directions_boat),
const Choice(title: 'This is a Bus', icon: Icons.directions_bus),
const Choice(title: 'This is a Train', icon: Icons.directions_railway),
];
class ChoiceCard extends StatelessWidget {
const ChoiceCard(
{Key key, this.choice, this.onTap, #required this.item, this.selected: false}
) : super(key: key);
final Choice choice;
final VoidCallback onTap;
final Choice item;
final bool selected;
#override
Widget build(BuildContext context) {
TextStyle textStyle = Theme.of(context).textTheme.display1;
if (selected)
textStyle = textStyle.copyWith(color: Colors.lightGreenAccent[400]);
return Card(
color: Colors.white,
child: Row(
children: <Widget>[
new Container(
padding: const EdgeInsets.all(8.0),
alignment: Alignment.topLeft,
child: Icon(choice.icon, size:80.0, color: textStyle.color,)),
new Expanded(
child: new Container(
padding: const EdgeInsets.all(10.0),
alignment: Alignment.topLeft,
child:
Text(choice.title, style: null, textAlign: TextAlign.left, maxLines: 5,),
)
),
],
crossAxisAlignment: CrossAxisAlignment.start,
)
);
}
}
You can copy paste run full code below
Step 1: To allow Navigator.push work, you can move MaterialApp to upper level
Step 2: In onTap pass Navigator.push
ChoiceCard(
choice: choices[index],
item: choices[index],
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Detail(choice: choices[index])),
);
},
),
Step 3: Wrap Card with InkWell and call onTap()
return InkWell(
onTap: () {
onTap();
},
child: Card(
working demo
full code
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(home: HomePage());
}
}
class HomePage extends StatelessWidget {
final title = "ListView List";
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(title),
),
body: new ListView(
shrinkWrap: true,
padding: const EdgeInsets.all(20.0),
children: List.generate(choices.length, (index) {
return Center(
child: ChoiceCard(
choice: choices[index],
item: choices[index],
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Detail(choice: choices[index])),
);
},
),
);
})));
}
}
class Choice {
const Choice({this.title, this.icon});
final String title;
final IconData icon;
}
const List<Choice> choices = const <Choice>[
const Choice(title: 'This is a Car', icon: Icons.directions_car),
const Choice(title: 'This is a Bicycle', icon: Icons.directions_bike),
const Choice(title: 'This is a Boat', icon: Icons.directions_boat),
const Choice(title: 'This is a Bus', icon: Icons.directions_bus),
const Choice(title: 'This is a Train', icon: Icons.directions_railway),
];
class ChoiceCard extends StatelessWidget {
const ChoiceCard(
{Key key,
this.choice,
this.onTap,
#required this.item,
this.selected: false})
: super(key: key);
final Choice choice;
final VoidCallback onTap;
final Choice item;
final bool selected;
#override
Widget build(BuildContext context) {
TextStyle textStyle = Theme.of(context).textTheme.display1;
if (selected)
textStyle = textStyle.copyWith(color: Colors.lightGreenAccent[400]);
return InkWell(
onTap: () {
onTap();
},
child: Card(
color: Colors.white,
child: Row(
children: <Widget>[
new Container(
padding: const EdgeInsets.all(8.0),
alignment: Alignment.topLeft,
child: Icon(
choice.icon,
size: 80.0,
color: textStyle.color,
)),
new Expanded(
child: new Container(
padding: const EdgeInsets.all(10.0),
alignment: Alignment.topLeft,
child: Text(
choice.title,
style: null,
textAlign: TextAlign.left,
maxLines: 5,
),
)),
],
crossAxisAlignment: CrossAxisAlignment.start,
)),
);
}
}
class Detail extends StatelessWidget {
final Choice choice;
Detail({this.choice});
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Second Route"),
),
body: Column(
children: <Widget>[
Text("${choice.title}"),
Center(
child: RaisedButton(
onPressed: () {
Navigator.pop(context);
},
child: Text('Go back!'),
),
),
],
),
);
}
}
import 'package:easy_buss/screen/client.dart';
import 'package:easy_buss/screen/invoice.dart';
import 'package:easy_buss/screen/invoice_settings.dart';
import 'package:easy_buss/screen/payment_info.dart';
import 'package:easy_buss/widgets/payment_info_form.dart';
import 'package:flutter/material.dart';
class Settings extends StatefulWidget {
#override
_SettingsState createState() => _SettingsState();
}
class _SettingsState extends State<Settings> {
List<IconData> _icon = [
Icons.accessible,
Icons.analytics,
Icons.question_answer_sharp,
Icons.message,
Icons.share,
Icons.star_half,
Icons.add_business,
Icons.privacy_tip,
];
List<String> _title = [
'Invoice Settings',
'Reports',
'Frequently Ask Questions',
'Write Us',
'Share With A Friends',
'Rate Us',
'Terms & Conditions',
'Privacy Policy',
];
List<Color> _colors = [
Colors.cyan,
Colors.yellow,
Colors.red,
Colors.purple,
Colors.orange,
Colors.grey,
Colors.pink[300],
Colors.green[200],
];
List _items = [
InvoiceSettings(),
InvoiceSettings(),
InvoiceSettings(),
InvoiceSettings(),
InvoiceSettings(),
InvoiceSettings(),
InvoiceSettings(),
InvoiceSettings(),
];
#override
Widget build(BuildContext context) {
return ListView.separated(
itemCount: _title.length,
separatorBuilder: (BuildContext context, int index) => Container(
padding: EdgeInsets.only(
left: 10,
right: 10,
),
child: Divider(
thickness: 1,
),
),
itemBuilder: (BuildContext context, int index) => ListTile(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => _items[index],
),
);
},
leading: Container(
padding: const EdgeInsets.all(5.0),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(10),
color: _colors[index],
),
child: Icon(
_icon[index],
color: Colors.white,
size: 20,
),
),
title: Text(
_title[index],
style: TextStyle(
fontWeight: FontWeight.bold,
),
),
trailing: Icon(
Icons.chevron_right,
size: 40,
),
),
);
}
}
Related
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_auth/firebase_auth.dart';
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: Authentication (),
);
}
}
class Authentication extends StatelessWidget {
const Authentication({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return StreamBuilder(
stream: FirebaseAuth.instance.authStateChanges(),
builder: (context, snapshot){
if(!snapshot.hasData){
return const SignInScreen(
providerConfigs: [
EmailProviderConfiguration()
],
);
}
return const Diarymain ();
},
);
}
}
class Diarymain extends StatefulWidget {
const Diarymain({Key? key}) : super(key: key);
#override
State<Diarymain> createState() => _DiarymainState();
}
class _DiarymainState extends State<Diarymain> {
final fbs = FirebaseDatabase.instance;
var currentUser = FirebaseAuth.instance.currentUser;
#override
Widget build(BuildContext context) {
final ref = fbs.ref().child('diary').child(currentUser!.uid);
return Scaffold(
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.grey[350],
onPressed: () {
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (_) => AddEditDiary(),
),
);
},
child: const Icon(
Icons.add,
),
),
appBar: AppBar(title: Text('Diary'),),
body: FirebaseAnimatedList(
query: ref,
shrinkWrap: true,
itemBuilder: (context, snapshot, animation, index) {
return GestureDetector(
onTap: () {},
child: Container(
child: Padding(
padding: const EdgeInsets.all(8.0),
// child: ListView.builder(
// itemBuilder: (context, index) {
child: ListTile(
shape: RoundedRectangleBorder(
side: const BorderSide(
color: Colors.white,
),
borderRadius: BorderRadius.circular(10),
),
tileColor: Colors.blue[50],
trailing: IconButton(
icon: Icon(
Icons.delete,
color: Colors.blueGrey[900],
),
onPressed: () {
ref.child(snapshot.key!).remove();
},
),
title: Text(
snapshot.value.toString(),
style: const TextStyle(
fontSize: 25,
fontWeight: FontWeight.bold,
),
),
),
// },)
),
),
);
},
),
);
}
}
class AddEditDiary extends StatefulWidget {
const AddEditDiary({Key? key}) : super(key: key);
#override
State<AddEditDiary> createState() => _AddEditDiaryState();
}
class _AddEditDiaryState extends State<AddEditDiary> {
TextEditingController title = TextEditingController();
TextEditingController subtitle = TextEditingController();
final fbs = FirebaseDatabase.instance;
var currentUser = FirebaseAuth.instance.currentUser;
#override
Widget build(BuildContext context) {
final ref = fbs.ref().child('diary').child(currentUser!.uid);
return Scaffold(
appBar: AppBar(title: Text('Add'),),
body: ListView(
children: <Widget> [
Padding(
padding: const EdgeInsets.all(8.0),
child: TextFormField(
controller: title,
decoration: InputDecoration(
labelText: 'Title',
hintText: 'Enter Title',
border: OutlineInputBorder(),
),
)
),
Padding(
padding: const EdgeInsets.all(8.0),
child: TextFormField(
controller: subtitle,
decoration: InputDecoration(
labelText: 'Subtitle',
hintText: 'Enter Subtitle',
border: OutlineInputBorder(),
),
)
),
Padding(
padding: const EdgeInsets.all(8.0),
child: RaisedButton(
onPressed: () {
ref
.push()
.set({
'title' : title.text,
'subtitle' : subtitle.text,
})
.asStream();
Navigator.pushReplacement(
context, MaterialPageRoute(builder: (_) => Diarymain()));
},
child: Text('Save', style: TextStyle(color: Colors.white),),
color: Colors.pink,
),
)
]
)
);
}
}
I'm trying to make a diary and two things which are title and subtitle are stored in the firebase real-time database. Below part of code shows how they are added in the firebase.
child: RaisedButton(
onPressed: () {
ref
.push()
.set({
'title' : title.text,
'subtitle' : subtitle.text,
})
.asStream();
When title and subtitles are shown on the page, I want to show them separately and I think I need something value to refer them individually.
In my code, "snapshot.value.toString()," shows only both title and subtitle together.
Is there any way to indicate them separately?
I would appreciate it if anyone can help me with this.
I am trying to understand how to return to a specific bottomtabindex. As of now I used a hacky way of ading an index to the HomePage as you can see. The issue is I cannot pass the Game object to HomePage too because it feels anti pattern. The Game Object should be passed to the Game Widget/screen
class HomePage extends StatefulWidget {
final int? index;
const HomePage({Key? key, this.index}) : super(key: key);
#override
State<HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
#override
void initState() {
super.initState();
_selectedIndex = widget.index?? 0;
}
int _selectedIndex = 0;
void _navigateBottomBar(int index) {
setState(() {
_selectedIndex = index;
});
}
List<Widget> screens = [
GameHistory(),
Game(),
Statistics(),
Help()
];
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Row(
children: <Widget>[
Image.asset("assets/images/logo.png", width: 50, height:50),
const Text("App")
],
),
backgroundColor: Colors.deepPurple,
elevation: 10.0,
actions: [
IconButton(
icon: const Icon(Icons.add_circle_outline),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => const CreateGame()),
);
},
)
],
),
body: screens[_selectedIndex],
bottomNavigationBar: Container(
color: Colors.black,
padding: const EdgeInsets.symmetric(horizontal: 15.0, vertical: 20),
child: GNav(
selectedIndex: _selectedIndex,
onTabChange: _navigateBottomBar,
backgroundColor: Colors.black,
color: Colors.white,
activeColor: Colors.white,
tabBackgroundColor: Colors.deepPurple,
gap: 8,
padding: const EdgeInsets.all(16),
tabs: const [
GButton(icon: Icons.home, text: 'Home'),
GButton(icon: Icons.play_arrow_outlined, text: 'Current Game',),
GButton(icon: Icons.leaderboard_outlined, text: 'Statistics'),
GButton(icon: Icons.help_outline_rounded, text: 'Rules'),
],),
),
);
}
}
//create game widget
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.deepPurple,
elevation: 10.0,
title: const Text('Create Game'),
),
body: Column(
children: [
const Padding(
padding: EdgeInsets.all(12.0),
child: Text("Team names"),
),
Padding(
padding: const EdgeInsets.all(12.0),
child: Row(children: [
Expanded(
child: TextField(
controller: player2,
decoration: const InputDecoration(hintText: "Playername"),
),
)
])
),
const Center(
child: Text("Versus",
style: TextStyle(fontWeight: FontWeight.bold),
),
),
Padding(
padding: const EdgeInsets.all(8.0),
child: Row(children: [
Expanded(
child: TextField(
controller: player4,
decoration: const InputDecoration(hintText: "Player name"),
),
)
])
),
const Text("Game Type"),
DropdownButton<String>(
value: gameType,
icon: const Icon(Icons.arrow_downward),
elevation: 16,
style: const TextStyle(color: Colors.deepPurple),
underline: Container(
height: 2,
color: Colors.deepPurpleAccent,
),
onChanged: (String? newValue) {
setState(() {
gameType = newValue!;
});
},
items: items
.map<DropdownMenuItem<String>>((String value) {
return DropdownMenuItem<String>(
value: value,
child: Text(value),
);
}).toList(),
),
Center(
child: ElevatedButton(
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all(Colors.black),
),
onPressed: () {
// Navigate to game screen and pass information
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(builder: (context) => const HomePage(index: 1,)),
(route) =>false,
);
},
child: const Text('Start Game!'),
),
),
],
),
);
}
}
I tried to create a task app using flutter, So I created a text field in DialogBox and my aim is when I add some text into the text field and when I clicked the OK button, I need to show that text in the list. but I have no idea how to call a method in another class, I've added my two classes.
ListTask Class
import 'package:flutter/material.dart';
class ListTask extends StatefulWidget {
const ListTask({Key? key}) : super(key: key);
#override
State<ListTask> createState() => _ListTaskState();
}
class _ListTaskState extends State<ListTask> {
final List<String> tasks = ['masu', 'adasf', 'wfqf', 'santha'];
final TextEditingController _textFieldController = TextEditingController();
void addItemToList() {
setState(() {
tasks.insert(0, _textFieldController.text);
});
}
#override
Widget build(BuildContext context) {
return Container(
height: 320,
width: double.maxFinite,
child: ListView.builder(
padding: EdgeInsets.only(bottom: 10),
itemCount: tasks.length,
itemBuilder: (context, index) {
return Card(
elevation: 1,
color: Colors.grey[200],
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
ExpansionTile(title: Text(tasks[index]), children: <Widget>[
ListTile(
title: Text(tasks[index]),
)
]),
],
),
);
},
),
);
}
Future<void> _displayTextInputDialog(BuildContext context) async {
return showDialog(
context: context,
builder: (context) {
return AlertDialog(
title: Text('TextField in Dialog'),
content: TextField(
onChanged: (value) {
setState(() {
// valueText = value;
});
},
controller: _textFieldController,
decoration: InputDecoration(hintText: "Text Field in Dialog"),
),
actions: <Widget>[
FlatButton(
color: Colors.red,
textColor: Colors.white,
child: Text('CANCEL'),
onPressed: () {
setState(() {
Navigator.pop(context);
});
},
),
FlatButton(
color: Colors.green,
textColor: Colors.white,
child: Text('OK'),
onPressed: () {
setState(() {
addItemToList();
Navigator.pop(context);
});
},
),
],
);
});
}
}
TaskApp Class
import 'package:flutter/material.dart';
import 'package:task_app/Widgets/listtasks.dart';
import 'package:task_app/Widgets/logo.dart';
import 'package:task_app/Widgets/searchbar.dart';
class TaskApp extends StatefulWidget {
const TaskApp({Key? key}) : super(key: key);
#override
State<TaskApp> createState() => _TaskAppState();
}
class _TaskAppState extends State<TaskApp> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Padding(
padding: const EdgeInsets.all(15.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
SizedBox(height: 10),
Logo(),
SizedBox(height: 0),
SearchBar(),
SizedBox(height: 15),
Column(
children: [
Text(
'All tasks',
style: TextStyle(fontWeight: FontWeight.bold, fontSize: 15.0),
)
],
),
SizedBox(height: 15),
ListTask(),
],
),
),
floatingActionButton: FloatingActionButton.extended(
onPressed: () {
_displayTextInputDialog(context);
},
label: const Text('Add Task'),
icon: const Icon(Icons.add),
backgroundColor: Colors.blue[900],
),
);
}
}
Calling point of that method in TaskApp Class:
Method:
You can give this a try, it will call a method defined in ListTask(StatefulWidget) from TaskApp(StatefulWidget) widget.
TaskApp.dart
import 'package:flutter/material.dart';
import 'package:vcare/Screens/tetxing1.dart';
class TaskApp extends StatefulWidget {
final ListTask listTask;
const TaskApp({Key? key,required this.listTask}) : super(key: key);
#override
State<TaskApp> createState() => _TaskAppState();
}
class _TaskAppState extends State<TaskApp> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Padding(
padding: const EdgeInsets.all(15.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
SizedBox(height: 10),
// Logo(),
SizedBox(height: 0),
//SearchBar(),
SizedBox(height: 15),
Column(
children: [
Text(
'All tasks',
style: TextStyle(fontWeight: FontWeight.bold, fontSize: 15.0),
)
],
),
SizedBox(height: 15),
ListTask(),
],
),
),
floatingActionButton: FloatingActionButton.extended(
onPressed: () {
ListTask().method1(context);
},
label: const Text('Add Task'),
icon: const Icon(Icons.add),
backgroundColor: Colors.blue[900],
),
);
}
}
ListTask.dart
import 'package:flutter/material.dart';
class ListTask extends StatefulWidget {
method1(context) => createState().displayTextInputDialog(context);
#override
_ListTaskState createState() => _ListTaskState();
}
class _ListTaskState extends State<ListTask> {
final List<String> tasks = ['masu', 'adasf', 'wfqf', 'santha'];
final TextEditingController _textFieldController = TextEditingController();
void addItemToList() {
setState(() {
tasks.insert(0, _textFieldController.text);
});
}
#override
Widget build(BuildContext context) {
return Container(
height: 320,
width: double.maxFinite,
child: ListView.builder(
padding: EdgeInsets.only(bottom: 10),
itemCount: tasks.length,
itemBuilder: (context, index) {
return Card(
elevation: 1,
color: Colors.grey[200],
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
ExpansionTile(title: Text(tasks[index]), children: <Widget>[
ListTile(
title: Text(tasks[index]),
)
]),
],
),
);
},
),
);
}
Future<void> displayTextInputDialog(BuildContext context) async {
return showDialog(
context: context,
builder: (context) {
return AlertDialog(
title: Text('TextField in Dialog'),
content: TextField(
onChanged: (value) {
setState(() {
// valueText = value;
});
},
controller: _textFieldController,
decoration: InputDecoration(hintText: "Text Field in Dialog"),
),
actions: <Widget>[
FlatButton(
color: Colors.red,
textColor: Colors.white,
child: Text('CANCEL'),
onPressed: () {
setState(() {
Navigator.pop(context);
});
},
),
FlatButton(
color: Colors.green,
textColor: Colors.white,
child: Text('OK'),
onPressed: () {
setState(() {
addItemToList();
Navigator.pop(context);
});
},
),
],
);
});
}
}
if you find this solution helpful please mark as accepted answer
I wanted to show dialog in my application. How can i achieve this using flutter
You can use a PopupMenuButton (https://api.flutter.dev/flutter/material/PopupMenuButton-class.html) to achieve this in flutter.
See example code below:
PopupMenuButton<int>(
itemBuilder: (context) => [
const PopupMenuItem(
value: 1,
child: Center(
child: Icon(
Icons.download_outlined,
size: 30.0,
),
),
),
const PopupMenuItem(
value: 2,
child: Center(
child: Icon(
Icons.link,
size: 30.0,
),
),
),
const PopupMenuItem(
value: 2,
child: Center(
child: Icon(
Icons.share,
size: 30.0,
),
),
),
],
icon: const Icon(
Icons.more_horiz,
size: 40.0,
),
offset: const Offset(150, -150),
);
The above example popups a list of Icons when the PopupMenuButton is pressed.
You can adapt this to your use-case above.
Finally I found a Solution thanks enfinity. Here how i solve the problem.
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
home: new MyHomePage(),
);
}
}
/// An arbitrary widget that lives in a popup menu
class PopupMenuWidget<T> extends PopupMenuEntry<T> {
const PopupMenuWidget({ Key key, this.height, this.child }) : super(key: key);
#override
final Widget child;
#override
final double height;
#override
bool get enabled => false;
#override
_PopupMenuWidgetState createState() => new _PopupMenuWidgetState();
}
class _PopupMenuWidgetState extends State<PopupMenuWidget> {
#override
Widget build(BuildContext context) => widget.child;
}
class MyHomePage extends StatelessWidget {
MyHomePage({Key key}) : super(key: key);
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
actions: <Widget>[
new PopupMenuButton<String>(
onSelected: (String value) {
print("You selected $value");
},
itemBuilder: (BuildContext context) {
return [
new PopupMenuWidget(
height: 40.0,
child: new Row(
children: [
IconButton(
icon: Icon(
Icons.remove,
color: Colors.green,
),
onPressed: () {
print("Remove");
}),
Text("1"),
IconButton(
icon: Icon(
Icons.add,
color: Colors.green,
),
onPressed: () {
print("Add");
}),
],
),
),
];
}
),
],
),
);
}
}
I wanted to send Data/images from one page to another. In the Homepage when I tap on the add Icon button image should be passed to the Cart page and if the icon is tapped again image is removed from the Cart page. But, the cart page should be accessed from bottom navigation bar.
but it is showing an error called 1 positional argument(s) expected, but 0 found.
Try adding the missing arguments.. when it calls the cart page.
HomePage.dart file
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blueGrey,
),
home: NavBar(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<Dish> _dishes = List<Dish>();
List<Dish> _cartList = List<Dish>();
#override
void initState() {
super.initState();
_populateDishes();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
actions: <Widget>[
Padding(
padding: const EdgeInsets.only(right: 16.0, top: 8.0),
child: GestureDetector(
child: Stack(
alignment: Alignment.topCenter,
children: <Widget>[
Icon(
Icons.shopping_cart,
size: 36.0,
),
if (_cartList.length > 0)
Padding(
padding: const EdgeInsets.only(left: 2.0),
child: CircleAvatar(
radius: 8.0,
backgroundColor: Colors.red,
foregroundColor: Colors.white,
child: Text(
_cartList.length.toString(),
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 12.0,
),
),
),
),
],
),
onTap: () {
if (_cartList.isNotEmpty)
Navigator.of(context).push(
MaterialPageRoute(
builder: (context) => Cart(_cartList),
),
);
},
),
)
],
),
body: _buildGridView(),
);
}
ListView _buildListView() {
return ListView.builder(
itemCount: _dishes.length,
itemBuilder: (context, index) {
var item = _dishes[index];
return Padding(
padding: const EdgeInsets.symmetric(
horizontal: 8.0,
vertical: 2.0,
),
child: Card(
elevation: 4.0,
child: ListTile(
leading: Icon(
item.icon,
color: item.color,
),
title: Text(item.name),
trailing: GestureDetector(
child: (!_cartList.contains(item))
? Icon(
Icons.add_circle,
color: Colors.green,
)
: Icon(
Icons.remove_circle,
color: Colors.red,
),
onTap: () {
setState(() {
if (!_cartList.contains(item))
_cartList.add(item);
else
_cartList.remove(item);
});
},
),
),
),
);
},
);
}
GridView _buildGridView() {
return GridView.builder(
padding: const EdgeInsets.all(4.0),
gridDelegate:
SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 2),
itemCount: _dishes.length,
itemBuilder: (context, index) {
var item = _dishes[index];
return Card(
elevation: 4.0,
child: Stack(
fit: StackFit.loose,
alignment: Alignment.center,
children: <Widget>[
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
item.icon,
color: (_cartList.contains(item))
? Colors.grey
: item.color,
size: 100.0,
),
Text(
item.name,
textAlign: TextAlign.center,
style: Theme.of(context).textTheme.subhead,
)
],
),
Padding(
padding: const EdgeInsets.only(
right: 8.0,
bottom: 8.0,
),
child: Align(
alignment: Alignment.bottomRight,
child: GestureDetector(
child: (!_cartList.contains(item))
? Icon(
Icons.add_circle,
color: Colors.green,
)
: Icon(
Icons.remove_circle,
color: Colors.red,
),
onTap: () {
setState(() {
if (!_cartList.contains(item))
_cartList.add(item);
else
_cartList.remove(item);
});
},
),
),
),
],
));
});
}
void _populateDishes() {
var list = <Dish>[
Dish(
name: 'Chicken Zinger',
icon: Icons.fastfood,
color: Colors.amber,
),
Dish(
name: 'Chicken Zinger without chicken',
icon: Icons.print,
color: Colors.deepOrange,
),
Dish(
name: 'Rice',
icon: Icons.child_care,
color: Colors.brown,
),
Dish(
name: 'Beef burger without beef',
icon: Icons.whatshot,
color: Colors.green,
),
Dish(
name: 'Laptop without OS',
icon: Icons.laptop,
color: Colors.purple,
),
Dish(
name: 'Mac wihout macOS',
icon: Icons.laptop_mac,
color: Colors.blueGrey,
),
];
setState(() {
_dishes = list;
});
}
}
Cart.dart file
import 'package:flutter/material.dart';
import 'dish_object.dart';
class Cart extends StatefulWidget {
final List<Dish> _cart;
Cart(this._cart);
#override
_CartState createState() => _CartState(this._cart);
}
class _CartState extends State<Cart> {
_CartState(this._cart);
List<Dish> _cart;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Cart'),
),
body: ListView.builder(
itemCount: _cart.length,
itemBuilder: (context, index) {
var item = _cart[index];
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 2.0),
child: Card(
elevation: 4.0,
child: ListTile(
leading: Icon(
item.icon,
color: item.color,
),
title: Text(item.name),
trailing: GestureDetector(
child: Icon(
Icons.remove_circle,
color: Colors.red,
),
onTap: () {
setState(() {
_cart.remove(item);
});
},
),
),
),
);
},
),
);
}
}
NavBar.dart file
import 'package:flutter/material.dart';
import 'package:sharewallpaper/cart.dart';
import 'package:sharewallpaper/main.dart';
class NavBar extends StatefulWidget {
#override
_NavBarState createState() => _NavBarState();
}
class _NavBarState extends State<NavBar> {
int _currentIndex = 0;
final List<Widget> _children = [
MyHomePage(),
Cart(), ** This line is throwing an error **
];
void onTappedBar(int index) {
setState(() {
_currentIndex = index;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: _children[_currentIndex],
bottomNavigationBar: BottomNavigationBar(
onTap: onTappedBar,
currentIndex: _currentIndex,
items: [
BottomNavigationBarItem(icon: Icon(Icons.home), title: Text('Home')),
BottomNavigationBarItem(
icon: Icon(Icons.bookmark), title: Text('BookMark')),
],
),
);
}
}
Yep, it will throw an error because the constructor of the Cart class is expecting one parameter to be passed in. You could use a named constructor instead like this:
class Cart extends StatefulWidget {
final List<Dish> _cart;
Cart(this._cart);
That way, you can call it like so:
Cart(cart: _cartList),
But if you actually need the cart list, I would recommend that you write a provider to keep track of the cart data across screens.