This question already has answers here:
Horizontal ListView flutter WITHOUT explicit height
(2 answers)
Closed 6 months ago.
I made list view with horizontal scrolling. And it is not working with out setting an height.
My code is
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text(""),
),
body: Column(
children: [
Container(
height: 100,
color: Colors.red,
child: ListView.builder(
itemCount: 5,
scrollDirection: Axis.horizontal,
itemBuilder: (BuildContext context, int index) {
return Card(
color: Colors.amberAccent,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(15.0),
),
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Text("$index"),
),
);
}),
),
const Expanded(child: Text("Some other views")),
],
),
),
);
}
}
How can I leave the listview height as wrap content?
That's one of the things you will have to live with. If there is a list of 1 million items and each one is wrap_content and somehow one of the list item is going to be 1000px in height, flutter has no way of knowing this as it only lays out items which are going to be visible (or has potential to be visible on user interaction immediately). It doesn't build all the million items at once so we need to provide some height.
This is true for vertical lists as well. We usually don't pay attention as most apps in portrait mode have not much width so it matches parent's width without any issue.
Related
I'm trying to use a GridView to handle displays for multiple Card, each Card contains of an Image. Unfortunately it turns out that the Image is taking a larger height than its parent (see attached picture for the details).
I'm pretty new to Flutter layout so any ideas why this is happening and how I can resolve this? I want the layout to be something like this:
Display 2 cards on each line.
The Card width or height should not be fixed.
The Image height should be scaled according to its width.
class SquadSelectionScreen extends StatelessWidget {
final List<Team> teams;
const SquadSelectionScreen({super.key, required this.teams});
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Squads'),
),
body: GridView.count(
crossAxisSpacing: 10,
crossAxisCount: 2,
padding: const EdgeInsets.all(16),
children: teams
.map(
(team) => SquadView(team: team),
)
.toList(),
),
);
}
}
class SquadView extends StatelessWidget {
final Team team;
const SquadView({super.key, required this.team});
#override
Widget build(BuildContext context) {
return InkWell(
onTap: () {
context.push('/squads/${team.code}');
},
child: Card(
elevation: 1,
child: Column(
children: [
Image(
image: NetworkImage(team.imageUrl),
),
const SizedBox(
height: 8,
),
Center(
child: Text(team.name),
),
],
),
),
);
}
}
Using GridView.count has a very visible drawback, namely the size of the aspect ratio of the grid will always be one (1:1 or Square) and can't be changed.
So if you look at the code above, you can't set an image with the same aspect ratio because the text will sink.
The first suggestion for me if you still want to use GridView.count is
Wrapping your Image with AspectRatio that has value higher than one (example set Ratio to 4/3, 5/3, 16/9, or landscape looks). Note: 4/3 = is higher than 1, 16/9 = is higher than 1, etc..
Then wrap the Text Widget with Expanded()
Example code:
class SquadView extends StatelessWidget {
final Team team;
const SquadView({super.key, required this.team});
#override
Widget build(BuildContext context) {
return InkWell(
onTap: () {},
child: Card(
elevation: 1,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
children: [
AspectRatio(
aspectRatio: 4/3, // you can set the value to 16/9 or anything that result is higher than one
child: Image(
image: NetworkImage(team.imageUrl),
fit: BoxFit.cover, // set How the image looks to Fit
),
),
const SizedBox(
height: 8,
),
Expanded(
child: Center(
child: Text(team.name, overflow: TextOverflow.ellipsis),
),
),
],
),
),
),
);
}
}
I suggest you try GridView.builder or another GridView. You can look at the documentation here
or this third package this will be good for to try flutter_staggered_grid_view. The flutter_staggered_grid_view is more flexible to create GridView with various size.
Hello I have a Scaffold wrapped with SingleChildScrollView and child is Column.
Inside Column; Container, TabBar and TabBarView.
First Container is just there for black space.
Container(
color: Colors.black,
height: 300,
),
The second widget of Column which mean TabBar:
(I know we can use it in AppBar but now it is what it is.)
const TabBar(
labelColor: Colors.red,
tabs: [
Tab(text: "Tab1"),
Tab(text: "Tab2"),
Tab(text: "Tab3"),
],
),
Last Column widget is TabBarView. It wrapped by Container that has 300 height.
Container(
height: 300, // here is problem
color: Colors.amber,
child: TabBarView(
children: [
buildContainer(200, Colors.red, 2),
buildContainer(100, Colors.red, 2),
buildContainer(150, Colors.red, 3),
],
),
),
and also this is buildContainer method;
buildContainer(double height, Color color, int count) => ListView.builder(
shrinkWrap: true,
itemCount: count,
itemBuilder: (BuildContext context, int index) {
return Padding(
padding: const EdgeInsets.all(8.0),
child: Container(
height: height,
color: color,
child: Center(
child: Text("my height ${height.toString()}"),
),
),
);
});
Here is my question. I have 3 tabs and I have three ListViewBuilder.Each one has own child count. But all of them height limited to 300 because of their parent that is Container. I want to set Tab's height dynamicly with each ListViewBuilder's item count.
How can I do that ? I accept dynamic height without child scrolling. I mean, I can scroll whole page for reach the last child. In example, Instagram profile tab. If I have 30 photo, height is phone height. But I have 300 photo, it scrolling all the way down. But also, I don't want to understand pagenation for this one. I am not going to do Instagram. I just want to that, If I create 5 container, okey show me your max height. If I create 1 container, show me just that without scrolling.
I added a dynamic height calculation depending on the number of objects in the ListView.builder. The formula is not perfect, you can add to it, but the point is to subtract the AppBar height and padding to get a clean screen area that the widget completely occupies.
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: mainWidget(),
);
}
Widget mainWidget() {
AppBar appBar = AppBar(
toolbarHeight: 56, //You can manually set the AppBar height
title: const Text("App bar"),
);
print(appBar.preferredSize); // Or you can save this value and use it later, it will not be fixed, but will depend on the screen size
return Scaffold(
appBar: appBar,
body: HelpSO(color: Colors.red, count: 5),
);
}
}
class HelpSO extends StatelessWidget {
late double height;
Color color;
int count;
HelpSO({Key? key, required this.color, required this.count})
: super(key: key);
#override
Widget build(BuildContext context) {
// height = (deviceHeight / itemCount) - padding (top + bottom) - appbar.prefferedSize.height / 2;
height = (MediaQuery.of(context).size.height / count) - 16.0 - 56 / 2;
return ListView.builder(
shrinkWrap: true,
itemCount: count,
itemBuilder: (BuildContext context, int index) {
return Padding(
padding: const EdgeInsets.all(8.0), // Subtract this value
child: Container(
height: height,
color: color,
child: Center(
child: Text("My height ${height.toString()}"),
),
),
);
});
}
}
I'm new at flutter(2 m).I just come accros with this problem.
My solution was juste wrap first or second(base on your logic) container with a SingleChildScrollView
Hope it will be helpful
I'm creating a ListView with a builder function. I use the widget inspector to assess the any issues with the layout of the widgets.
Usually, the listView shows downwards green arrows as shown here:
[ListView layout][1]
However, in my current app, whenever I create a listView, it shows this green overlay on the listView. This creates artefacts with Image widget nested in stack; the images flicker when scrolling. [artefact layout][2]
This layout does look like it will take the space of 'drawer' in scaffold however, this page does not have a drawer, although all the other pages do.
Please find the code below for your reference.
const BlogListPage({Key? key}) : super(key: key);
#override
State<BlogListPage> createState() => _BlogListPageState();
}
class _BlogListPageState extends State<BlogListPage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: ASAppBar(
title: const Text('Blogs'),
),
body: ListView.builder(
itemCount: 10,
itemBuilder: (BuildContext context, int index) {
return Container(
margin:
const EdgeInsets.symmetric(vertical: 16.0, horizontal: 24.0),
color: Colors.amber,
child: const SizedBox(
height: 100,
width: double.infinity,
),
);
},
));
}
} ```
[1]: https://i.stack.imgur.com/O7Pnc.png
[2]: https://i.stack.imgur.com/0g5HF.png
I have a Flutter Web application where I need to show a widget on the right side of a ListView when I click an item and this widget should always be visible on screen. I can achieve my objective puting both on a Row and using a scrollable only for the ListView, but that requires the ListView to be wrapped by a widget with defined height.
Defining a container with height to wrap the ListView breaks the responsiveness when I resize the browser, as the container doesn't fit the height of the screen.
I thought of using the shrinkWrap property of the ListView so I don't have to wrap it in a widget with predefined height, but that makes the whole Row scrollable vertically, eventually causing the widget to leave the viewport.
I would appreciate if somebody knows how could I keep this right side widget fixed on screen so I can achieve my objective without losing responsiveness.
Here's something similitar to what I've got so far:
class PageLayout extends StatefulWidget {
const PageLayout({Key? key, required this.items}) : super(key: key);
final List<String> items;
#override
State<PageLayout> createState() => _PageLayoutState();
}
class _PageLayoutState extends State<PageLayout> {
final rightSideWidget = Container(
decoration: BoxDecoration(
color: Colors.red,
border: Border.all(color: Colors.white, width: 2),
),
height: 200);
#override
Widget build(BuildContext context) {
return Scaffold(
body: SingleChildScrollView(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.start,
children: [
SizedBox(
width: MediaQuery.of(context).size.width * 0.49,
child: ListView.builder(
shrinkWrap: true,
itemBuilder: (context, index) => Container(
decoration: BoxDecoration(
color: Colors.blue,
border: Border.all(color: Colors.white, width: 2),
),
height: 200,
child: Center(
child: Text(
widget.items[index],
style: const TextStyle(color: Colors.white),
),
),
),
itemCount: widget.items.length,
),
),
Expanded(child: rightSideWidget),
],
),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
I want rightSideWidget to be always centered on screen or follow the scroll.
You can divide your screen into two sections, right section and left section; thereby being able to control behaviour of widgets in both sections.
Divide the overall screen into 2 proportional sections using a Row
widget
Put this Row widget inside a Container with height equal to screen height for preserving responsiveness | Use MediaQuery to get current height of page
Now left hand section can individually scroll, and on click of any option from this section you can define behaviour for right section; while keeping the left section constant throughout page lifecycle
I'm trying to create a 2x2 grid for displaying some info in cards. Disclaimer: I'm totally new to Dart and Flutter, so expect a lot of ignorance on the topic here.
These cards should have a fixed size, have an image, display some text... and be positioned from left to right, from top to bottom.
First, I tried to use the Flex widget, but it seems to only work horizontally or vertically. Therefore, my only solution was to use two Flexes, but only showing the second when the amount of elements is higher than 2 (which would only use one row).
Then, I tried using GridView, but it doesn't work in any possible way. It doesn't matter which example from the Internet I copy and paste to begin testing: they just won't show up in the screen unless they're the only thing that is shown in the app, with no other widget whatsoever. I still don't understand why that happens.
This is my current code:
First widgets in "home_page.dart":
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
Padding(padding: EdgeInsets.only(top: 30)),
Text(
'App test',
style: TextStyle(fontSize: 24),
),
EventsList(key: new Key('test')),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
The "EventList" part is a widget that should represent the grid functionality I explained before. This class gets some info from a service (which currently just sends some hardcoded info from a Future), and paints the given widgets ("Card" items, basically) into the EventList view:
class _EventsListState extends State<EventsList> {
#override
Widget build(BuildContext context) {
return FutureBuilder<List<Event>>(
future: new EventsService().getEventsForCoords(),
builder: (context, AsyncSnapshot<List<Event>> snapshot) {
if (snapshot.hasData) {
return Padding(
padding: EdgeInsets.only(left: 20, right: 20),
child: Flex(
direction: Axis.horizontal,
verticalDirection: VerticalDirection.down,
mainAxisAlignment: MainAxisAlignment.center,
children: generateProximityEventCards(snapshot.data),
));
} else {
return CircularProgressIndicator();
}
});
}
List<Card> generateProximityEventCards(List<Event> eventList) {
// Load Events from API
print(eventList);
// Render each card
return eventList.map((Event ev) {
return Card(
child: Padding(
padding: EdgeInsets.only(bottom: 15),
child: Column(
children: <Widget>[
Image(
fit: BoxFit.cover,
image: ev.imageUrl,
height: 100,
width: 150,
),
Padding(
child: Text(ev.name),
padding: EdgeInsets.only(left: 10, right: 10),
),
Padding(
child: Text(ev.address),
padding: EdgeInsets.only(left: 10, right: 10),
),
],
),
));
}).toList();
}
}
This is how it currently looks:
As I said before, I understand that the Flex widget can't really get that 2x2 grid look that I'm looking for, which would be something like this (done with Paint):
So, some questions:
How can I get a grid like that working? Have in mind that I want to have more stuff below that, so it cannot be an "infinite" grid, nor a full window grid.
Is it possible to perform some scrolling to the right in the container of that grid? So in case there are more than 4 elements, I can get to the other ones just scrolling with the finger to the right.
As you can see in the first image, the second example is bigger than the first. How to limit the Card's size?
Thank you a lot for your help!
The reason the gridview was not working is because you need to set the shrinkWrap property of theGridView to true, to make it take up as little space as possible. (by default, scrollable widgets like gridview and listview take up as much vertical space as possible, which gives you an error if you put that inside a column widget)
Try using the scrollable GridView.count widget like this and setting shrinkWrap to true:
...
GridView.count(
primary: false,
padding: /* You can add padding: */ You can add padding const EdgeInsets.all(20),
crossAxisCount: /* This makes it 2x2: */ 2,
shrinkWrap: true,
children: generateProximityEventCards(snapshot.data),
...
Is this what you exactly want?
do let me know so that I can update the code for you
import 'package:flutter/material.dart';
class List extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.white,
title: Text('Inicio', style: TextStyle(color: Colors.black, fontSize: 18.0),),
),
body: GridView.count(
shrinkWrap: true,
crossAxisCount: 2,
children: List.generate(
50,//this is the total number of cards
(index){
return Container(
child: Card(
color: Colors.blue,
),
);
}
),
),
);
}
}