I'm pretty new at Flutter and trying to make a simple app, where I fetch data with an API and trying to show the results.
This function is responsible to get the data (this function works fine, I get the data):
Connection connection = Connection();
String textValue = '';
Future<void> createlist() async {
List<MoviesByTitle> movieTitle = [];
String response = await connection.getMovieByTitle();
var data = jsonDecode(response);
var results = data['results'];
for (int i = 0; i < results.length; i++) {
movieTitle.add(
MoviesByTitle(
movieId: results[i]['id'],
title: results[i]['original_title'],
shortDescription: results[i]['overview'],
year: results[i]['release_date'],
),
);
}
}
And here comes the screen itself:
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Movies app"),
),
body: Column(
children: [
TextField(
decoration: const InputDecoration(
border: OutlineInputBorder(),
labelText: 'Movie title',
),
onSubmitted: (value) {
textValue = value;
},
onChanged: (value) {
textValue = value;
},
),
TextButton(
onPressed: () {
createlist();
},
child: Text("Press"),
),
Expanded(
child: ListView.builder(
itemCount: 30,
itemBuilder: (BuildContext context, int index) {
return Card(
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
children: [
Text("Movie title"),
Text("Short decscription"),
],
),
),
);
}),
),
],
),
bottomNavigationBar: BottomMenu(),
);
}
What I want is: if the TextButton is pressed to show the data of the movies in separate cards. Somehow I can not find a way to create cards dynamically based on the data from the API (maybe I will wrap the ListView builder with a Visibility widget).
Is there any way to change the number of the card and their content dynamically?
You have added the items tothe list movieTitle.. you can use that as a reference to build the ui.. You can try
ListView.builder(
itemCount: movieTitle.length,
itemBuilder: (BuildContext context, int index) {
return Card(
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
children: [
Text("${movieTitle[index].title}"),
Text("${movieTitle[index].shortDescription}>"),
],
),
),
);
}),
Also you may have to move the movieTitle variable outside the fetch api method so it can be accessed from the ui part too.
Related
I'm trying to build a shopping list based on meals ingredients that are passed in Route Settings on which user can select/deselect each items separately. Here is the code:
import 'package:cookup/src/consts/colors.dart';
import 'package:flutter/material.dart';
import '/dummy_data.dart';
class ShoppingListScreen extends StatefulWidget {
static const routeName = '/shoppig-list';
final Function toggleFavorite;
final Function isFavorite;
ShoppingListScreen(this.toggleFavorite, this.isFavorite);
#override
State<ShoppingListScreen> createState() => _ShoppingListScreenState();
}
class _ShoppingListScreenState extends State<ShoppingListScreen> {
bool isSelected = false;
#override
Widget build(BuildContext context) {
final mealId = ModalRoute.of(context)?.settings.arguments as String;
final selectedMeal = DUMMY_MEALS.firstWhere((meal) => meal.id == mealId);
return Scaffold(
appBar: AppBar(
iconTheme: IconThemeData(color: kFontColorBlack),
backgroundColor: kBackgroundColor,
title: Text(
'${selectedMeal.title}',
maxLines: 2,
overflow: TextOverflow.ellipsis,
textAlign: TextAlign.center,
style: TextStyle(color: kFontColorBlack),
),
actions: [
IconButton(
icon: Icon(
widget.isFavorite(mealId)
? Icons.favorite
: Icons.favorite_border,
),
onPressed: () => widget.toggleFavorite(mealId),
),
],
),
body: SingleChildScrollView(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Container(
height: 250,
width: double.infinity,
child: Image.network(
selectedMeal.imageUrl,
fit: BoxFit.cover,
),
),
Container(
alignment: Alignment.topLeft,
margin: EdgeInsets.symmetric(vertical: 10),
child: const Padding(
padding: EdgeInsets.all(16.0),
child: Text(
"Ingredients",
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 22.0,
),
),
),
),
ListView.builder(
itemCount: selectedMeal.ingredients.length,
shrinkWrap: true,
physics: const NeverScrollableScrollPhysics(),
itemBuilder: (context, index) {
return CheckboxListTile(
title: Text(selectedMeal.ingredients[index]),
value: isSelected,
controlAffinity: ListTileControlAffinity.leading,
onChanged: (
value,
) {
setState(() {
isSelected = value!;
});
},
);
},
),
],
),
),
);
}
}
and the result is visible here as I got stuck having all items being selcted/deselected on click:
enter image description here
Which is not the expeted behaviour as I need only one item being seletced on click. I was trying variious things but end up having either the above result, having some error regaridng incorrect list Range or I got error that dependOnInheritedWidgetOfExactType<_ModalScopeStatus>() or dependOnInheritedElement() was called before _ShoppingListScreenState.initState() completed. What I am doing wrong? Please help! :)
The reason why you are getting this error is you are passing the same value
isSelected in all your items in the ListView.builder.
You have to add a boolean field in your model class which will store the value for each and every item in your list.
Consider following example for model class.
class DummyMeals {
final String name;
final String id;
bool isSelected;
DummyMeals({
required this.name,
required this.id,
this.isSelected = false,
});
}
ListView.builder(
itemCount: itemList.length,
shrinkWrap: true,
physics: const NeverScrollableScrollPhysics(),
itemBuilder: (context, index) {
return CheckboxListTile(
key: Key('$index'),
title: Text(itemList[index].name),
value: itemList[index].isSelected,
controlAffinity: ListTileControlAffinity.leading,
onChanged: (val) {
setState(() {
itemList[index].isSelected = !itemList[index].isSelected;
});
},
);
},
),
Hope this helps !
Thanks! I have updated the model from the list to a map with a boolean value and used below builder code - it works as expected now:
ListView.builder(
itemCount: selectedMeal.ingredients.length,
shrinkWrap: true,
physics: const NeverScrollableScrollPhysics(),
itemBuilder: (context, index) {
final ingredient =
selectedMeal.ingredients.keys.toList()[index];
return CheckboxListTile(
title: Text(ingredient),
key: Key(ingredient),
value: selectedIngredients[ingredient] ?? false,
controlAffinity: ListTileControlAffinity.leading,
onChanged: (
value,
) {
setState(() {
selectedIngredients[ingredient] = value!;
});
},
);
},
),
Hello I have 2 list and I want to use these in ListViewBuilder.
List's:
List times = ['08:30', '09:00', '09:30', '10:00', '13:00'];
List obj = [true,false,true];
I tried this:
ListView.builder(
controller: scrollController,
shrinkWrap: true,
itemCount: times.length,
itemBuilder: (BuildContext context, int index) {
return Padding(
padding: const EdgeInsets.all(8.0),
child: InkWell(
onTap: () {
setState(() {
selected = index;
debugPrint(tarih[index]);
});
},
child: Container(
color: obj[index] ? Colors.yellow : Colors.red,
height: 30,
width: 12,
child: Text(times[index]),
),
),
);
},
),
Here is the error:
I know what cause's this error. Because of obj.length does not match with times.length
But I still want to create the other Containers.
How do I solve this?
Many ways you can avoid this here min(int,int) method used lowest integer find
obj[min(index,obj.length-1)] ? Colors.yellow : Colors.red,
widget may like this
ListView.builder(
// controller: scrollController,
shrinkWrap: true,
itemCount: times.length,
itemBuilder: (BuildContext context, int index) {
return Padding(
padding: const EdgeInsets.all(8.0),
child: InkWell(
onTap: () {
setState(() {
selected = index;
// debugPrint(tarih[index]);
});
},
child: Container(
color: obj[min(index,obj.length-1)] ? Colors.yellow : Colors.red,
height: 30,
width: 12,
child: Text(times[index]),
),
),
);
},
)
You try to achieve dartpad live
class _MyAppState extends State<MyApp> {
int selected = 0;
#override
void initState() {
super.initState();
}
List times = ['08:30', '09:00', '09:30', '10:00', '13:00'];
List obj = [];
#override
Widget build(BuildContext context) {
var column = Column(
children: [
Container(
height: 200,
child: Row(
children: [
Expanded(
child: Image.network(
"https://upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Salto_del_Angel-Canaima-Venezuela08.JPG/1200px-Salto_del_Angel-Canaima-Venezuela08.JPG",
// fit: BoxFit.cover,
fit: BoxFit.fitWidth,
),
),
],
),
)
],
);
obj = List.generate(times.length, (index) => false);
var children2 = [
ListView.builder(
// controller: scrollController,
shrinkWrap: true,
itemCount: times.length,
itemBuilder: (BuildContext context, int index) {
if (selected == index)
obj[index] = true;
else
obj[index] = false;
return Padding(
padding: const EdgeInsets.all(8.0),
child: InkWell(
onTap: selected != index
? () {
setState(() {
selected = index;
print(selected);
// debugPrint(tarih[index]);
});
}
: null,
child: Container(
color: obj[index]
? Colors.yellow
: Colors.red,
height: 30,
width: 12,
child: Text(times[index]),
),
),
);
},
),
DropdownButton(
items: [
DropdownMenuItem(
child: Text("1"),
value: "1",
onTap: () {},
)
],
onChanged: (values) {
// _dropdown1=values;
})
];
return MaterialApp(
// theme: theme(),
debugShowCheckedModeBanner: false,
home: Scaffold(
appBar: AppBar(),
body: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: children2,
)),
);
}
}
Well there might be other ways to do so, what I did was, just to copy the obj list items as many as there are items in times list in order. And if the number is not equal just add remaining number at last.
List times = [
'08:30',
'09:00',
'09:30',
'10:00',
'13:00',
'13:00',
'13:00',
'13:00',
'13:00',
];
List obj = [true, false, true];
#override
Widget build(BuildContext context) {
// Remaining length of times list after we copy
int remaining = times.length % obj.length;
//Exact Number of times to copy obj
int exactNumber = (times.length - remaining) ~/ obj.length;
List shallowList = [];
// Using for loop copy the list as many as exactNumber
for (int i = 0; i < exactNumber; i++) {
shallowList += obj;
}
// Add add remaining subList
// Then we have obj list with same length as times
List finalShallowList = [...shallowList, ...obj.sublist(0, remaining)];
// Create Separate Index for obj that we can reset
return Scaffold(
body: Container(
child: ListView.builder(
shrinkWrap: true,
itemCount: times.length,
itemBuilder: (BuildContext context, int index) {
return Padding(
padding: const EdgeInsets.all(8.0),
child: InkWell(
onTap: () {},
child: Container(
// Loop over finalShallowList instead of obj
color: finalShallowList[index] ? Colors.yellow : Colors.red,
height: 30,
width: 12,
child: Text(times[index]),
),
),
);
},
),
),
);
Hey guys I need help with removing this button and load data from json file without need to click on that button
Here's code
List _items = [];
// Fetch content from the json file
#override
Widget build(BuildContext context) {
Future readJson() async {
final String response =
await rootBundle.loadString('assets/aaaa.json');
final data = await json.decode(response);
setState(() {
_items = data['first'];
});
}
return Scaffold(
body: Padding(
padding: const EdgeInsets.all(25),
child: Column(
children: [
ElevatedButton(
child: const Text('Load Data'),
onPressed: readJson,
),
// Display the data loaded from sample.json
_items.isNotEmpty
? Expanded(
child: ListView.builder(
itemCount: _items.length,
itemBuilder: (context, index) {
return Card(
margin: const EdgeInsets.all(10),
child: ListTile(
leading: Text(_items[index]["aaaaa"]),
title: Text(_items[index]["aaaaa"]),
subtitle: Text(_items[index]["aaaaaa"]),
),
);
},
),
)
: Container()
],
),
),
);
}
You should check out Future Builder. There are some good examples on that page of how to use the widget, including how to show different widgets depending on if the data was loaded, is in the process of loading, or there was an error. readJson would be the future in your case.
Call initState() before build function
#overrride
initState() {
readJson();
super.initState();
}
Calling the readJson() function just before returning Scaffold will do what you want.
Widget build(BuildContext context) {
//load the json content
readJson();
return Scaffold(
body: Padding(
padding: const EdgeInsets.all(25),
child: Column(
children: [
// Display the data loaded from sample.json
_items.isNotEmpty
? Expanded(
child: ListView.builder(
itemCount: _items.length,
itemBuilder: (context, index) {
return Card(
margin: const EdgeInsets.all(10),
child: ListTile(
leading: Text(_items[index]["aaaaa"]),
title: Text(_items[index]["aaaaa"]),
subtitle: Text(_items[index]["aaaaaa"]),
),
);
},
),
)
: Container()
],
),
),
);}
I actually have a searchBar(autocomplete) that is working.
When i select a result, the displaySnack() is working, it displays a snackBar, but i would like to display the content of testList().
My goal is to understand how I can launch another widget, to be able to add new widget on the page again and again.
My final goal is once i have the selected value, to make an http request, get a list as return and display a listview.
The function is executed ( i can see it in debugger ) but doesn't display anything..
(i'm new to flutter, so please explain your response if possible :) )
onSuggestionSelected : yes i know that it is void..
import 'package:drawer/src/share/snack_bar.dart';
import 'package:flutter/material.dart';
import 'package:flutter_typeahead/flutter_typeahead.dart';
import '../models/post_model.dart';
import '../services/http_service.dart';
// import 'package:http/http.dart' as http;
class PostsPage extends StatelessWidget {
final String title;
const PostsPage({Key? key, required this.title}) : super(key: key);
static Future<List<Post>> filterList(String value) async {
List<Post> list = await HttpService.fetchPosts();
return list.where(
(x) => x.title.toLowerCase().contains(value.toLowerCase())).toList();
}
#override
Widget build(BuildContext context) => Scaffold(
appBar: AppBar(
title: Text(title),
),
body: SafeArea(
child: Container(
padding: EdgeInsets.all(16),
child: TypeAheadField<Post?>(
debounceDuration: Duration(milliseconds: 500),
hideSuggestionsOnKeyboardHide: false,
textFieldConfiguration: TextFieldConfiguration(
decoration: InputDecoration(
prefixIcon: Icon(Icons.search),
border: OutlineInputBorder(),
hintText: 'Select the namespace...',
),
),
suggestionsCallback: filterList,
itemBuilder: (context, Post? suggestion) {
final user = suggestion!;
return ListTile(
title: Text(user.title),
);
},
noItemsFoundBuilder: (context) => Container(
height: 100,
child: Center(
child: Text(
'No Namespace Found.',
style: TextStyle(fontSize: 24),
),
),
),
onSuggestionSelected: (Post? suggestion) {
final user = suggestion!;
displaySnack(context, ' Namespace: '+user.title);
testList(context); ################################ HERE
},
),
),
),
);
}
Widget testList(BuildContext context) {
return ListView.separated(
separatorBuilder: (BuildContext context, int index) => const Divider(),
itemCount: 2,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text("ppp"),
subtitle: Text("ppp"),
leading: CircleAvatar(
backgroundImage: NetworkImage(
"https://images.unsplash.com/photo-1547721064-da6cfb341d50"))
));
});
}
I need that : https://prnt.sc/136njev
It is obvious that you want the widget to rebuild to show the result. The most straightforward method is to use StatefulWidget. So I use it in your case(You can also find lots of ways to manage the state List of state management approaches)
Change your PostsPage to a StatefulWidget and rebuild when the user is selected
Add a Column in your PostsPage and separate into 2 parts: TypeAheadField & Result
Result part can use FutureBuilder (which can show loading indicator when data is not ready)
PostsPage:
class PostsPage extends StatefulWidget {
final String title;
const PostsPage({Key? key, required this.title}) : super(key: key);
static Future<List<Post>> filterList(String value) async {
// skip
}
#override
_PostsPageState createState() => _PostsPageState();
}
class _PostsPageState extends State<PostsPage> {
Post? user;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: SafeArea(
child: Column(
children: [
Container(
padding: EdgeInsets.all(16),
child: TypeAheadField<Post>(
// ...
// skip
// ...
onSuggestionSelected: (Post? suggestion) {
setState(() {
user = suggestion!;
displaySnack(context, ' Namespace: '+user.title);
});
},
),
),
Expanded(child: MyResult(post: user)),
],
),
),
);
}
}
Result part:
(I make it an isolated StatelessWidget just for better reading. You can use the original method to build the widget)
class MyResult extends StatelessWidget {
const MyResult({
required this.post,
Key? key,
}) : super(key: key);
final Post? post;
Future<List<OtherObject>> getOtherObjects(Post? post) async{
if(post == null){
return [];
}else{
return Future.delayed(Duration(seconds:3),()=>[OtherObject(title: '001'),OtherObject(title: '002'),OtherObject(title: '003')]);
}
}
#override
Widget build(BuildContext context) {
return FutureBuilder<List<OtherObject>>(
future: getOtherObjects(post),
builder: (context, snapshot) {
if(snapshot.hasData && snapshot.connectionState == ConnectionState.done) {
final result = snapshot.data!;
return ListView.separated(
separatorBuilder: (BuildContext context,
int index) => const Divider(),
itemCount: result.length,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text(result[index].title),
subtitle: Text("ppp"),
leading: CircleAvatar(
backgroundImage: NetworkImage(
"https://images.unsplash.com/photo-1547721064-da6cfb341d50"),
),
),
);
},
);
}else {
return Center(child: CircularProgressIndicator());
}
}
);
}
}
So what you are doing is basically just creating a ListView with your testList() function call and doing nothing with it, but what you want to do is to have that widget show up on the screen, right?
Flutter doesn't just show Widget if you create a new one, you must tell it to render. Just imagine you are doing preparing Widgets (e.g. Widgets in Widgets) and Flutter would render it immediately to the screen without you being finished, that wouldn't be that great.
You need to push that Widget over the Navigator widget that Flutter provides you.
onSuggestionSelected: (Post? suggestion) {
final user = suggestion!;
displaySnack(context, ' Namespace: '+user.title);
Navigator.push(
context,
MaterialPageRoute(builder: (context) => testList(context)),
);
}
I suggest you to read this article to Navigation Basics.
you can use listView builder to show the selected results.
onSuggestionSelected: (Post? suggestion) {
final user = suggestion!;
displaySnack(context, ' Namespace: '+user.title);
//get results
var results = fetchResult(suggestion);
//return a listview of the results
return ListView.builder(
physics: const AlwaysScrollableScrollPhysics(),
shrinkWrap: true,
scrollDirection: Axis.vertical,
itemCount: results.length,
itemBuilder: (_context, index) {
Post post = results[index];
return Card(
elevation: 2,
child: InkWell(
child: Container(
padding: EdgeInsets.symmetric(horizontal: 8, vertical: 8),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(6.0),
border: Border.all(color: Colors.black),
),
child: DefaultTextStyle(
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 12,
color: Colors.white),
child: Row(children: [
Expanded(
flex: 2,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(post.data),
],
),
),
]),
),
),
onTap: () {
//do something when user clicks on a result
},
));
}
},
If you want to show a list of selected items then you will have to add a ListView in the widget tree. Also use a StatefullWidget instead of StatelessWidget, because whenever you select an item, the selected list gets changed thus state.
sample code for state
List<Post> selectedPosts;
#override
void initState() {
super.initState();
selectedPosts = [];
}
#override
Widget build(BuildContext context) => Scaffold(
appBar: AppBar(
title: Text(title),
),
body: SafeArea(
child: Column(
children: [
Container(
padding: EdgeInsets.all(16),
child: TypeAheadField<Post?>(
debounceDuration: Duration(milliseconds: 500),
hideSuggestionsOnKeyboardHide: false,
textFieldConfiguration: TextFieldConfiguration(
decoration: InputDecoration(
prefixIcon: Icon(Icons.search),
border: OutlineInputBorder(),
hintText: 'Select the namespace...',
),
),
suggestionsCallback: filterList,
itemBuilder: (context, Post? suggestion) {
final user = suggestion!;
return ListTile(
title: Text(user.title),
);
},
noItemsFoundBuilder: (context) => Container(
height: 100,
child: Center(
child: Text(
'No Namespace Found.',
style: TextStyle(fontSize: 24),
),
),
),
onSuggestionSelected: (Post? suggestion) {
final user = suggestion!;
displaySnack(context, ' Namespace: '+user.title);
setState(()=> selectedPosts.add(suggestion));
},
),
),
testList(context),
],
),
),
);
and in the testList function change the itemcount
itemCount: 2,
to
itemCount: selectedPosts?.length ?? 0,
How to control listviewbuilder from outside the listview in flutter?
In a textfield I can use a controller like so: controller: Textcontroller. Can I do something similar in listviewbuilder to clear all the objects in it?
So to be exact. My code looks something like this
Expanded(
child: new ListView.builder(
itemCount: List.length,
itemBuilder: (context,index){
return new Card(
//all stuff with data
),
),
);
},
....
How would I do so that when called from another function it removes all the items in the listview?
You need a Store class that holds this list along with list manipulation methods, then you can use provider for example to access that class and render that list.
You can define a variable in the state of your widget:
var _clear = false;
When this variable is true, the list will be cleared and when it's false, the list will be displayed. You can use setState to toggle this variable. Setting the itemCount of the ListView.builder to 0 clears the list.
Full code:
var _clear = false;
#override
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children: <Widget>[
Padding(
padding: const EdgeInsets.all(30.0),
child: FlatButton(
child: Text('clear'),
color: Colors.pinkAccent,
onPressed: () {
setState(() {
_clear = true;
});
},
),
),
FlatButton(
child: Text('add'),
color: Colors.greenAccent,
onPressed: () {
setState(() {
_clear = false;
});
},
),
Expanded(
child: ListView.builder(
controller: _scrollController,
itemCount: _clear ? 0 : 100,
itemBuilder: (context, index) {
return Container(
height: 300,
child: Card(
child: Center(
child: Text('$index'),
),
),
);
},
),
),
],
),
);
}