sujith sa
Reputation: 37
Flutter update data onClick at clicked index
I am building a food cart application and have a query on the menu item page.
My menu items page consists of a list view, which shows each item with description along with an option to specify the quantity of items( 1, 2, 3....)
Now I am able to increment or decrement item count for a single item, but not sure how to do that in a list view at a particular index where the user clicks.
Could some one please help me on this?
The code which I have done till now is as below :
FutureBuilder(
future: getItemList(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return CircularProgressIndicator();
}
var itemList = snapshot.data;
int itemlength = itemList.length;
return ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemBuilder: (BuildContext context, int index) {
return Container(
height: 100,
margin: EdgeInsets.only(left: 10, right: 10, top: 10),
decoration: BoxDecoration(
color: Colors.white70,
border: Border.all(width: 2.0, color: Colors.blueGrey),
borderRadius: BorderRadius.circular(6.0),
boxShadow: [
BoxShadow(
color: Color(0xFF6078ea).withOpacity(.3),
offset: Offset(0.0, 8.0),
blurRadius: 8.0),
],
),
child: Row(
children: < Widget > [
Container(
width: 75,
child: ClipRRect(
borderRadius: new BorderRadius.circular(10.0),
child: Image(
image: AssetImage(
'assets/images/loginbg3.jpg'),
fit: BoxFit.cover,
),
),
margin: EdgeInsets.only(left: 10),
),
Expanded(
child: Container(
child: Column(
children: < Widget > [
Row(
children: < Widget > [
Expanded(child: Container(margin: EdgeInsets.only(left: 10, top: 15, bottom: 5), child: Text(itemList[index]['itemname'], style: kClickableTextStyle, ))),
Container(color: Colors.white, width: 25, margin: EdgeInsets.only(left: 10, top: 15, bottom: 5), child: Image.asset(_itemtype)),
],
),
Row(
children: < Widget > [
Container(margin: EdgeInsets.only(left: 10, top: 15, bottom: 5), child: Text('Price : ', style: kListTitleTextStyle, )),
Container(margin: EdgeInsets.only(left: 10, top: 15, bottom: 5), child: Text(numberofitems.toString() + ' \u20B9 ', style: kListTitleTextStyle, )),
],
),
],
),
),
),
Container(
margin: EdgeInsets.only(left: 10),
child: Row(
children: < Widget > [
InkWell(
onTap: onClickDelete,
child: Container(
width: 30, child: Icon(
Icons.remove_circle_outline,
color: Colors.green,
size: 30,
), ),
),
Container(
width: 30,
child: Center(child: Text(_count.toString(), style: TextStyle(fontSize: 25), )),
),
InkWell(
onTap: onClickAdd,
child: Container(
margin: EdgeInsets.only(right: 5),
width: 30, child: Icon(
Icons.add_circle_outline,
color: Colors.green,
size: 30,
), ),
),
],
),
),
],
),
);
},
itemCount: itemList == null ? 0 : itemList.length,
);
})
Upvotes: 1
Views: 4013
Answers (3)
chunhunghan
Reputation: 54427
You can copy paste run full code below
Step 1: create Item class
Step 2: change future builder call
Step 3: deal with Inkwell onTap
working demo
code snippet
Future callback;
@override
void initState() {
callback = _getItemList();
super.initState();
}
@override
Widget build(BuildContext context) {
var futureBuilder = FutureBuilder(
future: callback,
...
InkWell(
onTap: () {
if (itemList[index].numberofitems > 0) {
setState(() {
itemList[index].numberofitems =
itemList[index].numberofitems - 1;
});
}
},
...
InkWell(
onTap: () {
setState(() {
itemList[index].numberofitems =
itemList[index].numberofitems + 1;
print(
' ${itemList[index].itemname.toString()} ${itemList[index].numberofitems.toString()}');
});
},
full code
import 'dart:async';
import 'dart:collection';
import 'package:flutter/material.dart';
void main() => runApp( MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class Item {
String itemname;
String itemtype;
int numberofitems;
Item({this.itemname, this.itemtype, this.numberofitems});
}
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
Future callback;
@override
void initState() {
callback = _getItemList();
super.initState();
}
@override
Widget build(BuildContext context) {
var futureBuilder = FutureBuilder(
future: callback,
builder: (BuildContext context, AsyncSnapshot snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
case ConnectionState.waiting:
return Center(child: CircularProgressIndicator());
default:
if (snapshot.hasError)
return Text('Error: ${snapshot.error}');
else
return createListView(context, snapshot);
}
},
);
return Scaffold(
appBar: AppBar(
title: Text("Home Page"),
),
body: futureBuilder,
);
}
Future<List<Item>> _getItemList() async {
var values = List<Item>();
values.add(
Item(itemname: "A", itemtype: "assets/images/a.jpg", numberofitems: 0));
values.add(
Item(itemname: "B", itemtype: "assets/images/a.jpg", numberofitems: 1));
values.add(
Item(itemname: "C", itemtype: "assets/images/a.jpg", numberofitems: 2));
//throw Exception("Danger Will Robinson!!!");
await Future.delayed( Duration(seconds: 2));
return values;
}
Widget createListView(BuildContext context, AsyncSnapshot snapshot) {
List<Item> itemList = snapshot.data;
return ListView.builder(
itemCount: itemList.length,
itemBuilder: (BuildContext context, int index) {
{
return Container(
height: 100,
margin: EdgeInsets.only(left: 10, right: 10, top: 10),
decoration: BoxDecoration(
color: Colors.white70,
border: Border.all(width: 2.0, color: Colors.blueGrey),
borderRadius: BorderRadius.circular(6.0),
boxShadow: [
BoxShadow(
color: Color(0xFF6078ea).withOpacity(.3),
offset: Offset(0.0, 8.0),
blurRadius: 8.0),
],
),
child: Row(
children: <Widget>[
Container(
width: 75,
child: ClipRRect(
borderRadius: BorderRadius.circular(10.0),
child: Image(
image: AssetImage('assets/images/a.jpg'),
fit: BoxFit.cover,
),
),
margin: EdgeInsets.only(left: 10),
),
Expanded(
child: Container(
child: Column(
children: <Widget>[
Row(
children: <Widget>[
Expanded(
child: Container(
margin: EdgeInsets.only(
left: 10, top: 15, bottom: 5),
child: Text(
itemList[index].itemname,
))),
Container(
color: Colors.white,
width: 25,
margin: EdgeInsets.only(
left: 10, top: 15, bottom: 5),
child: Image.asset(itemList[index].itemtype)),
],
),
Row(
children: <Widget>[
Container(
margin: EdgeInsets.only(
left: 10, top: 15, bottom: 5),
child: Text(
'Price : ',
)),
Container(
margin: EdgeInsets.only(
left: 10, top: 15, bottom: 5),
child: Text(
itemList[index].numberofitems.toString() +
' \u20B9 ',
)),
],
),
],
),
),
),
Container(
margin: EdgeInsets.only(left: 10),
child: Row(
children: <Widget>[
InkWell(
onTap: () {
if (itemList[index].numberofitems > 0) {
setState(() {
itemList[index].numberofitems =
itemList[index].numberofitems - 1;
});
}
},
child: Container(
width: 30,
child: Icon(
Icons.remove_circle_outline,
color: Colors.green,
size: 30,
),
),
),
Container(
width: 30,
child: Center(
child: Text(
itemList[index].numberofitems.toString(),
style: TextStyle(fontSize: 25),
)),
),
InkWell(
onTap: () {
setState(() {
itemList[index].numberofitems =
itemList[index].numberofitems + 1;
print(
' ${itemList[index].itemname.toString()} ${itemList[index].numberofitems.toString()}');
});
},
child: Container(
margin: EdgeInsets.only(right: 5),
width: 30,
child: Icon(
Icons.add_circle_outline,
color: Colors.green,
size: 30,
),
),
),
],
),
),
],
),
);
}
;
});
}
}
Upvotes: 2
Faiq Mustaqeem
Reputation: 96
you need to create list of objects for your Item like.
class Item{
String name;
String description;
int quantity;
double price;
}
and on tap of item, get index of clicked item with new incremented/decremented value and update your list of objects inside setState().
Upvotes: 2
Anirudh Bagri
Reputation: 2447
You need to wrap your itemBuilder item, i.e the Container with a GestureDetector and then call the onTap() method inside that detector.
Before that, you'll have to convert your item into a stateful widget with a variable to maintain the count of quantity.
Upvotes: 0
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