I have a image slider in flutter where I want to vertically center the carousel. I'm using carousel_slider. And this here is my code:
Widget _buildItems(BuildContext context) {
return Column(
children: <Widget>[
appBar(context),
Center(
child: CarouselSlider(
options: CarouselOptions(
enlargeCenterPage: true,
enableInfiniteScroll: false,
autoPlay: false,
),
items: widget.recipeStepsList!
.map(
(e) => ClipRRect(
borderRadius: BorderRadius.circular(8),
child: Stack(
fit: StackFit.expand,
children: <Widget>[
Container(
child: Text(
e.name!,
style: TextStyle(color: Colors.red),
),
),
Image.network(
e.stepThumbnailLink!,
width: 1000,
height: 200,
fit: BoxFit.cover,
),
],
),
),
)
.toList(),
),
),
],
);
}
As you can see, I've already wrapped everything inside a Center but this is the outcome of my code:
The only reason the back button is in place because it has a padding of 10. But since I'm building this application for all types of screens I need to keep the image slider exactly in the center.
The carousel is not coming in the center, since your Center widget is not actually taking up the full space and this is because it is inside a Column.
For widget like Row and Column, you can use Expanded widget to make any child take up the remaining space.
So, for your case, just wrap your Center inside an Expanded.
Here is the linkk to full working code.
Result,
Ignore the overflow warning, since that is happening because the carousel package is squishing view while scrolling.
i am trying to align list view items at the top left, but it aligns them in the center. I tried this with another widget, it works fine, but with the listview, it doesn't.
here is my code
Container(
height: height * 30,
// color: Colors.grey[400],
alignment: Alignment.topLeft,
child: ListView.builder(
itemBuilder: (context, i) => ReviewItem(
review: book.reviews[i]['review'],
date: book.reviews[i]['date'],
),
itemCount: book.reviews.length,
),
),
this is the review item
Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(
timeago.format(DateTime.parse(date)),
style: Theme.of(context).textTheme.headline4.copyWith(
fontSize: width * kFont12Ratio, color: Colors.grey[500]),
),
SizedBox(height: height * 0.5),
Text(review),
Divider(),
],
);
Thanks in advance
By default, ListView will automatically pad the list's scrollable extremities to avoid partial obstructions indicated by MediaQuery's padding. In other words, if you put a widget before the ListView, you should wrap the ListView with a MediaQuery.removePadding widget (with removeTop: true). Like so:
MediaQuery.removePadding(
context: context,
removeTop: true,
child: ListView.builder(...),
);
I achieved that by adding padding inside the listview builder
padding: EdgeInsets.only(top: 0),
You can use padding instead
Or use Stack with Position (top:0,left:0)
Or use Align( )
I'm building out an app in flutter and I want to display a few cards in a list-view. The problems I'm facing are the following:
I get a text-overflow when I have Text widgets in a column.I semi-fixed this by wrapping the Text widget in an Expanded widget, but it looks a bit cutoff (ex. "Question: How do you do problem 2?" (refer to picture below)).
I want to build a larger card with a greater height and more room/white space. I've tried wrapping my column widget in a container and set the height manually, but that doesn't seem to do anything.
Here is what the card looks like right now:
Relevant code shown below:
itemBuilder: (context, index) => snapshot
.data.metadata.isFromCache
? _buildListItem(context,
snapshot.data.documents[index])
Widget _buildListItem(BuildContext context, DocumentSnapshot document) {
return document.data['didProblems']
? Card(
child: Center(
child: Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text('${document.data['fullName'].toString()}'),
SizedBox(
height: 5.0,
),
Text('HW Assignment: ${document.data['title'].toString()}'),
SizedBox(
height: 5.0,
),
Text('Problems attempted: ${document.data['problems']}'),
Expanded(child: Text('Question: ${document.data['question'].toString()}'), flex: 1,),
],
),
),
),
)
Any help is appreciated. Thanks in advance!
if u r using listview then set itemExtent property to ur convenience e.g.
ListView.builder(
itemCount: 10,
itemBuilder: (_, int index) => YourWidget(),
itemExtent: 150,
),
Even after wrapping your text in an Expanded you have to set overflow to TextOverflow.clip
Try this
Expanded(child: Text('Question: ${document.data['question'].toString()}', overflow: TextOverflow.clip), flex:1,),
I am making an ipad in flutter. I have a date picker. But in landscape it is showing pretty big.
Is there any way to resize the date picker dialog
Yes, you can resize date picker dialog by Container(), SizedBox() etc. using it in builder, but only if you put it in something like Column(), for example:
return showDatePicker(
context: context,
initialDate: DateTime.now(),
firstDate: DateTime.now(),
lastDate: DateTime.now().add(Duration(days: 356)),
builder: (context, child) {
return Column(
children: <Widget>[
Padding(
padding: const EdgeInsets.only(top: 50.0),
child: Container(
height: 450,
width: 700,
child: child,
),
),
],
);
},
);
With newer flutter version date picker is smaller and no longer takes up most of the screen
https://github.com/flutter/flutter/pull/50546
In Android match_parent and wrap_content are used to resize the widgets automatically relative to their parent to the content the widget contains.
In Flutter it seems by default all widgets are set to wrap_content, how would I change it such that I can fill its width and height to that of its parent?
You can do with little Trick:
Suppose you have requirement of :
( Width,Height )
Wrap_content ,Wrap_content :
//use this as child
Wrap(
children: <Widget>[*your_child*])
Match_parent,Match_parent:
//use this as child
Container(
height: double.infinity,
width: double.infinity,child:*your_child*)
Match_parent,Wrap_content :
//use this as child
Row(
mainAxisSize: MainAxisSize.max,
children: <Widget>[*your_child*],
);
Wrap_content ,Match_parent:
//use this as child
Column(
mainAxisSize: MainAxisSize.max,
children: <Widget>[your_child],
);
In order to get behavior for match_parent and wrap_content we need to
use mainAxisSize property in Row/Column widget, the mainAxisSize
property takes MainAxisSize enum having two values which is
MainAxisSize.min which behaves as wrap_content and MainAxisSize.max
which behaves as match_parent.
Link of the original Article
The short answer is that the parent doesn't have a size until the child has a size.
The way layout works in Flutter is that each widget provides constraints to each of its children, like "you can be up to this wide, you must be this tall, you have to be at least this wide", or whatever (specifically, they get a minimum width, a maximum width, a minimum height, and a maximum height). Each child takes those constraints, does something, and picks a size (width and height) that matches those constraints. Then, once each child has done its thing, the widget can can pick its own size.
Some widgets try to be as big as the parent allows. Some widgets try to be as small as the parent allows. Some widgets try to match a certain "natural" size (e.g. text, images).
Some widgets tell their children they can be any size they want. Some give their children the same constraints that they got from their parent.
There are actually some options available:
You can use SizedBox.expand to make your widget match parents dimensions, or SizedBox(width: double.infinity) to match only the width or SizedBox(heigth: double.infinity) to match only the heigth.
If you want a wrap_content behavior it depends on the parent widget you are using, for example if you put a button on a column it will behave like wrap_content and to use it like match_parent you can wrap the button with a Expanded widget or a sizedbox.
With a ListView the button gets a match_parent behavior and to get a wrap_content behavior you can wrap it with a Flex widget like Row.
Using an Expanded widget makes a child of a Row, Column, or Flex
expand to fill the available space in the main axis (e.g., horizontally for
a Row or vertically for a Column).
https://docs.flutter.io/flutter/widgets/Expanded-class.html
Using a Flexible widget gives a child of a Row, Column, or Flex the flexibility to expand to fill the available space in the main axis (e.g., horizontally for a Row or vertically for a Column), but, unlike Expanded, Flexible does not require the child to fill the available space.
https://docs.flutter.io/flutter/widgets/Flexible-class.html
Use the widget Wrap.
For Column like behavior try:
return Wrap(
direction: Axis.vertical,
spacing: 10,
children: <Widget>[...],);
For Row like behavior try:
return Wrap(
direction: Axis.horizontal,
spacing: 10,
children: <Widget>[...],);
For more information: Wrap (Flutter Widget)
I used this solution, you have to define the height and width of your screen using MediaQuery:
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width
)
To make a child fill its parent, simply wrap it into a FittedBox
FittedBox(
child: Image.asset('foo.png'),
fit: BoxFit.fill,
)
A simple workaround:
If a container has only one top level child, then you can specify alignment property for the child and give it any available value. it'll fill all the space in the container.
Container(color:Colors.white,height:200.0,width:200.0,
child:Container(
color: Colors.yellow,
alignment:Alignment.[any_available_option] // make the yellow child match the parent size
)
)
Another way:
Container(color:Colors.white,height:200.0,width:200.0,
child:Container(
color: Colors.yellow,
constraints: BoxConstraints.expand(height: 100.0), // height will be 100 dip and width will be match parent
)
)
Stack(
children: [
Container(color:Colors.red, height:200.0, width:200.0),
Positioned.fill(
child: Container(color: Colors. yellow),
)
]
),
Use FractionallySizedBox widget.
FractionallySizedBox(
widthFactor: 1.0, // width w.r.t to parent
heightFactor: 1.0, // height w.r.t to parent
child: *Your Child Here*
}
This widget is also very useful when you want to size your child at a fraction of its parent's size.
Example:
If you want the child to occupy 50% width of its parent, provide widthFactor as 0.5
Match Parent
To match or fill the parent (height & width) we can use additional constraints on Container:
Container(
constraints: BoxConstraints.expand(), // ← this guy
child: Text('Center > Container > Text')
)
In Flutter, constraints are the space you can fill (or must fill, if "tight" constraints).
Constraints are given... no actually, imposed by parents.
By default, Container will wrap its content (child:) & size itself to its child, unless overriden (or not allowed by tight constraints).
Using the constraints: argument, we can give Container additional constraints to override default Container constraint behavior (such as wrapping content).
Using Container(constraints: BoxConstraints.something) doesn't overwrite incoming/parent constraints; It just allows us to override default behavior, where allowed, such as wrapping content.
Code Sample - BoxConstraints
Here's a copy/paste code example showing effects of various constraints we can apply to a Container that has "loose" incoming/parental constraints (provided by Center).
import 'package:flutter/material.dart';
class MatchParentPage extends StatefulWidget {
#override
_MatchParentPageState createState() => _MatchParentPageState();
}
class _MatchParentPageState extends State<MatchParentPage> {
BoxConstraints constraints;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Match Parent'),
),
body: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Expanded( // shares space constraint evenly with other Expanded
child: Center( // ← fills tight parent constraint & loosens ↓ child constraint ↓
child: Container( // got loose constraint from Center...
constraints: constraints, // can apply many additional constraints
color: Colors.lightBlueAccent.withOpacity(.3),
child: Text('Center > Container > Text')),
),
),
Expanded(
child: Container(
color: Colors.orangeAccent,
child: Wrap(
children: [
_button('default', null),
_button('*expand()', BoxConstraints.expand()),
_button('*tight(Size.infinite)', BoxConstraints.tight(Size.infinite)),
_button('tight(Size.zero)', BoxConstraints.tight(Size.zero)),
_button('tight(Size.fromHeight(100))', BoxConstraints.tight(Size.fromHeight(100))),
_button('tight(Size.fromWidth(100))', BoxConstraints.tight(Size.fromWidth(100))),
_button('tightForFinite(width: 100, height: 100)', BoxConstraints.tightForFinite(width: 100, height: 100)),
_button('loose(Size.infinite)', BoxConstraints.loose(Size.infinite)),
_button('tightFor(width: double.infinity)', BoxConstraints.tightFor(width: double.infinity)),
_button('tightFor(height: double.infinity)', BoxConstraints.tightFor(height: double.infinity)),
])
),
)
],
),
);
}
Widget _button(String label, BoxConstraints _constraints) {
bool _active = _constraints == constraints;
return Padding(
padding: const EdgeInsets.only(top:8, left: 8),
child: RaisedButton(
color: _active ? Colors.cyanAccent : null,
child: Text(label),
onPressed: () {
setState(() => constraints = _constraints);
},
),
);
}
}
Use this line of codes inside the Column.
For wrap_content : mainAxisSize: MainAxisSize.min
For match_parent : mainAxisSize: MainAxisSize.max
MATCH_PARENT
FractionallySizedBox(
widthFactor: 1.0, // width w.r.t to parent
heightFactor: 1.0, // height w.r.t to parent
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
)
OR
Container(
height: double.infinity,
width: double.infinity,
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
)
OR
Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
)
OR
Container(
constraints: BoxConstraints.expand(),
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
)
WRAP_CONTENT
Wrap(children: [
Container(
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
),
])
OR
Container(
constraints: BoxConstraints.tightFor(),
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
)
Match_parent,Wrap_content :
Row(
children: [
Expanded(
child: Container(
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
),
),
])
Wrap_content,Match_parent :
Column(
children: [
Expanded(
child: Container(
child: ElevatedButton(
onPressed: () {},
child: Text("+"),
),
),
),
])
For match parent option you can wrap your widget by a container and give it a width like this
width: double.infinity
this approach will make the widget fill max space available for it on the screen.