I have a ListView.builder that uses shrinkWrap because I get an error if I don't use it.
As a result of this answer, there will be a lot of white space above ListView.builder:
How can I remove it?
My code:
SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
"Summary",
maxLines: 1,
overflow: TextOverflow.ellipsis,
),
const SizedBox(height: 20.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
…
],
),
ListView.builder(
shrinkWrap: true,
cacheExtent: 9999,
itemCount: list.length,
itemBuilder: (context, index) => ListTile(…),
),
],
),
),
Feel free to leave a comment if you need more information.
How can I change the position of the ListView.builder that uses shrinkWrap?
Instead of using ListView.builder, you should use Column:
Column(
children: list.map((element) => …).toList(),
),
I don't know by "space above ListView.builder" or "How can I change the position of the ListView.builder that uses shrinkWrap?" what you mean
Possible solutions considering all cases:
If it's outside the ListView is because of wrapping it in Center which is obvious.
If you are referring to the top margin inside the ListView it is because of this line margin: EdgeInsets.all(32),
You just have to remove Center widget, it will change it's position to the start of the app.
Extra: You can remove the default padding of ListView.builder by adding padding:EdgeInsets.zero. If this is what you are talking about.
Scaffold(
body: Container(
decoration: BoxDecoration(
border: Border.all(color: Colors.red), color: Colors.amber),
child: ListView(
padding: EdgeInsets.zero,
shrinkWrap: true,
children: const <Widget>[
ListTile(title: Text('Item 1')),
ListTile(title: Text('Item 2')),
ListTile(title: Text('Item 3')),
],
),
)),
Note: You dont have to use shrinkWrap:true everytime , it is preferred to be used, only when your listView is inside another Scrollable view. Else it is preferred to be false which is the option by default
Refer the docs:
Shrink wrapping the content of the scroll view is significantly more expensive than expanding to the maximum allowed size because the content can expand and contract during scrolling, which means the size of the scroll view needs to be recomputed whenever the scroll position changes.
While looking for solutions, I found some related discussions, but none of the solutions worked in my case.
I made a "RefreshableScrollFrame" widget in my app, which offers a generic frame for pages that should show a StatusBar (loading indicator, etc.) and which should provide a pull-down to refresh.
RefreshableScrollFrame
return Center(
child: Column(
children: [
SizedBox(
height: 4,
child: const MyStatusbarWidget(),
),
RefreshIndicator(
onRefresh: onRefresh,
child: SingleChildScrollView(
physics: const AlwaysScrollableScrollPhysics(),
child: child,
),
)
],
),
);
Child Option - ListView:
ListView.builder(
itemCount: items.length,
physics: const NeverScrollableScrollPhysics(),
shrinkWrap: true,
itemBuilder: (context, i) => Card(
child: ListTile(
title: Text(items[i].name),
),
),
);
Child Option - Column with the ListView and static items:
Column(
children: [
ListView.builder(
itemCount: items.length,
physics: const NeverScrollableScrollPhysics(),
shrinkWrap: true,
itemBuilder: (context, i) => Card(
child: ListTile(
title: Text(items[i].name),
),
),
),
...someStaticWidgets,
],
);
So far so good, everything works fine, except for one important detail.
The RefreshIndicator is only triggered in areas, which are covered by the child widget. If the content is small and covers just the top of the page, the gesture is detected only in that area.
If the content is just an empty ListView, I won't even be able to trigger a refresh.
I tried several suggested solutions in order to "expand" the child to the whole screen, but I always ran into exceptions, when trying to get rid of shrinkWrap, when adding Expanded(), and so on.
Any hints would be appreciated.
you have to wrap the whole body of your scaffold with refreshIndicator not a portion of it.
I found a solution that seems to work for me, using a LayoutBuilder + ConstrainedBox to wrap the contents of the SingleChildScrollView.
This way, the SingleChildScrollView will always span the whole remaining space.
return Column(
children: [
const SizedBox(
height: 4,
child: MyStatusbarWidget(),
),
Expanded(
child: LayoutBuilder(builder: (context, constraints) {
return RefreshIndicator(
onRefresh: onRefresh,
child: SingleChildScrollView(
physics: const AlwaysScrollableScrollPhysics(),
child: ConstrainedBox(
constraints: BoxConstraints(minHeight: constraints.maxHeight),
child: child,
),
),
),
);
}),
),
],
);
Idea is to put a ListView.builder and an Image together side by side horizontally.
So, I put the ListView.builder and the Image in a Row.
This Row is inside a ListView which has other children too.
The problem is that before I introduced the Row, the ListView.builder was showing up properly. Now with Row, ListView.builder and an Image are NOT being shown.
There are no errors, just the contents are invisible.
Row(
children: <Widget>[
ListView.builder
(
shrinkWrap: true,
physics: ClampingScrollPhysics(),
itemCount: list3.length,
itemBuilder: (BuildContext ctxt, int Index)
{
return new ListView
(
shrinkWrap: true,
padding: const EdgeInsets.all(1),
children: <Widget>
[
ListTile(
leading: CircleAvatar(
radius: 6.0,
backgroundColor: Colors.black,
),
title : Text(list3[Index], style: TextStyle(color: Colors.red, fontSize: 25,),)
),
]
);
},
),
Expanded(
child: Image(
image: NetworkImage('https://flutter.github.io/assets-for-api-docs/assets/widgets/owl.jpg'),
height: 15,
width: 15,
fit: BoxFit.cover,
)
),
],
),
Wrap your ListView.builder with Expanded.
The ListView is inside a Row and needs a width, so that the other element can expand in the remaining area. So wrap it inside a SizedBox.
SizedBox(
width: 300,
child: ListView.builder(),
)
I am trying to add a GestureDetector on my ListView widget which contains Images but it does not seem to work. A similar question has been asked about it before but that did not help either.
Here is my code:
ListView.builder(
scrollDirection: Axis.horizontal,
itemBuilder: (BuildContext ctx, int index) {
return Container(
width: 160,
child: Card(
child: Wrap(
children: <Widget>[
GestureDetector( onTap: () => Print_on_layout(index),
child: Image.network(a[index], fit: BoxFit.fill,)
)
],
),
),
);
},
itemCount: a.length,
),
I suppose this has something to do with the wrap Widget, which might be messing with the space where the tap can be detected. Try removing it. If that doesn't work, please tell us if you get an error.
Use gesturedetector as a parent of the container not on image.
as in the list you are only returning a single widgit so you should container with gesture detector.
Try this code:
ListView.builder(
scrollDirection: Axis.horizontal,
itemBuilder: (BuildContext ctx, int index) {
return
GestureDetector(onTap: () => Print_on_layout(index),
child: Container(
width: 160,
child: Card(
child: Wrap(
children: <Widget>[
Image.network(a[index], fit: BoxFit.fill,)
],
),
),
),
);
},
itemCount: a.length,
),
I'm trying to construct a simple login page for my Flutter app. I've successfully built the TextFields and log in/Sign in buttons. I want to add a horizontal ListView. When I run the code my elements disappear, if I do it without the ListView, it's fine again. How can I do this correctly?
return new MaterialApp(
home: new Scaffold(
appBar: new AppBar(
title: new Text("Login / Signup"),
),
body: new Container(
child: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new TextField(
decoration: new InputDecoration(
hintText: "E M A I L A D D R E S S"
),
),
new Padding(padding: new EdgeInsets.all(15.00)),
new TextField(obscureText: true,
decoration: new InputDecoration(
hintText: "P A S S W O R D"
),
),
new Padding(padding: new EdgeInsets.all(15.00)),
new TextField(decoration: new InputDecoration(
hintText: "U S E R N A M E"
),),
new RaisedButton(onPressed: null,
child: new Text("SIGNUP"),),
new Padding(padding: new EdgeInsets.all(15.00)),
new RaisedButton(onPressed: null,
child: new Text("LOGIN"),),
new Padding(padding: new EdgeInsets.all(15.00)),
new ListView(scrollDirection: Axis.horizontal,
children: <Widget>[
new RaisedButton(onPressed: null,
child: new Text("Facebook"),),
new Padding(padding: new EdgeInsets.all(5.00)),
new RaisedButton(onPressed: null,
child: new Text("Google"),)
],)
],
),
),
margin: new EdgeInsets.all(15.00),
),
),
);
I've got this problem too. My solution is use Expanded widget to expand remain space.
Column(
children: <Widget>[
Expanded(
child: horizontalList,
)
],
);
Reason for error:
Column expands to the maximum size in main axis direction (vertical axis), and so does the ListView.
Solutions:
So, you need to constrain the height of the ListView. There are many ways of doing it, you can choose that best suits your need.
If you want to allow ListView to take up all remaining space inside Column, use Expanded.
Column(
children: <Widget>[
Expanded( // <-- Use Expanded
child: ListView(...),
)
],
)
If you want to limit your ListView to a certain height, use SizedBox.
Column(
children: <Widget>[
SizedBox(
height: 200, // Constrain height.
child: ListView(...),
)
],
)
If your ListView is small, you may try shrinkWrap property on it.
Column(
children: <Widget>[
ListView(
shrinkWrap: true, // Set this
)
],
)
If you want to make ListView to as small as it can be, use Flexible with ListView.shrinkWrap:
Column(
children: <Widget>[
Flexible( // <-- Use Flexible
child: ListView(
shrinkWrap: true, // and set this
),
)
],
)
You can check console output. It prints error:
The following assertion was thrown during performResize():
The horizontal viewport was given unbounded height.
Viewports expand in the cross axis to fill their container and constrain their children to match
their extent in the cross axis. In this case, a horizontal viewport was given an unlimited amount of
vertical space in which to expand.
You need to add a height constraint to your horizontal list. E.g. wrap in Container with height:
Container(
height: 44.0,
child: ListView(
scrollDirection: Axis.horizontal,
children: <Widget>[
RaisedButton(
onPressed: null,
child: Text("Facebook"),
),
Padding(padding: EdgeInsets.all(5.00)),
RaisedButton(
onPressed: null,
child: Text("Google"),
)
],
),
)
Expanded Widget increases its size as much as it can with the space available Since ListView essentially has an infinite height it will cause an error.
Column(
children: <Widget>[
Flexible(
child: ListView(...),
)
],
)
Here we should use the Flexible widget as it will only take the space it required as Expanded take full screen even if there are not enough widgets to render on full screen.
I have SingleChildScrollView as a parent, and one Column Widget and then List View Widget as last child.
Adding these properties in List View Worked for me.
physics: NeverScrollableScrollPhysics(),
shrinkWrap: true,
scrollDirection: Axis.vertical,
As have been mentioned by others above,Wrap listview with Expanded is the solution.
But when you deal with nested Columns you will also need to limit your ListView to a certain height (faced this problem a lot).
If anyone have another solution please, mention in comment or add answer.
Example
SingleChildScrollView(
child: Column(
children: <Widget>[
Image(image: ),//<< any widgets added
SizedBox(),
Column(
children: <Widget>[
Text('header'), //<< any widgets added
Expanded(child:
ListView.builder(
//here your code
scrollDirection: Axis.horizontal,
itemCount: items.length,
itemBuilder: (BuildContext context, int index) {
return Container();
}
)
),
Divider(),//<< any widgets added
],
),
],
),
);
Actually, when you read docs the ListView should be inside Expanded Widget so it can work.
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children: <Widget>[
Align(
child: PayableWidget(),
),
Expanded(
child: _myListView(context),
)
],
));
}
You can use Flex and Flexible widgets. for example:
Flex(
direction: Axis.vertical,
children: <Widget>[
... other widgets ...
Flexible(
flex: 1,
child: ListView.builder(
itemCount: ...,
itemBuilder: (context, index) {
...
},
),
),
],
);
[Solution Preview] - [List Items are scrollable but heading is fixed]
I have very small & straight forward answer, see putting listview inside column will force column to expand infinitely, which is basically an error thing.
Now if you put physics: NeverScrollableScrollPhysics(), like others suggested, in listview then whats the point of having listview if you disable scrolling inside it..
There is an easy fix, frankly I landed on this by hit and trial. Let me give you small explanation after code.
Column(
children: [
Text(
"All Bookings",
style: TextStyle(fontSize: 20, fontWeight: FontWeight.w600, color: Colors.brown[700]),
),
Expanded(
child: Container(
margin: EdgeInsets.only(top: 24),
child: ListView.builder(
itemCount: 30,
itemBuilder: (BuildContext context, int index) => ListTile(
title: Text("List Item ${index + 1}"),
),
),
),
),
],
)
I had requirement to have title inside Column as first element & then put a Listview so that user can have scrolling list. This is a generic kind of requirement. You can put this in Bottom Sheet or Modal too.
Code Explanation:
I kept first child as heading inside Column ok (which i donot want to scroll away, i want it to be fixed)
I have Expanded child inside column, which is like acquire all the "remaining space" in column.
Inside that I kept container (Just to put some space between title & list view with margin) this is optional, you can remove container and it will still work.
Now the Listview is well constrained and it won't try to stretch infinitely in column. As Expanded widget already constrained it.
Please correct me if I am wrong anywhere or if this code doesn't work (it works as of now without errors :)
Wrap your Listview with Expanded Widget
Column(
children: <Widget>[
Text('Leading text widget'),
ListView(
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
children: <Widget>[
ListTile(
leading: Icon(Icons.map),
title: Text('Map'),
),
ListTile(
leading: Icon(Icons.photo_album),
title: Text('Album'),
),
ListTile(
leading: Icon(Icons.phone),
title: Text('Phone'),
),
],
),
Text('More widget'),
],
);
just use
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
properties in listView
You need to do 2 things:
wrap Column inside SingleChildScrollView
add shrinkWrap: true and physics: NeverScrollableScrollPhysics() in ListView
Why it works:
As I uderstand, NeverScrollableScrollPhysics disable scrolling of ListView.
So, scroll works with SingleChildScrollView.
If I am wrong, comment bellow.
SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text('Filter'),
ListView.separated(
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
itemCount: rides.length,
itemBuilder: (BuildContext context, int index) {
# return some widget
}
),
In my case, I was using
singleChildScrollView
Column
Container
FutureBuilder
- Listview
and I wanted to scroll last scroll view with the whole column
for this add
physics: NeverScrollableScrollPhysics(),
this line in your listview.
Try using Slivers:
Container(
child: CustomScrollView(
slivers: <Widget>[
SliverList(
delegate: SliverChildListDelegate(
[
HeaderWidget("Header 1"),
HeaderWidget("Header 2"),
HeaderWidget("Header 3"),
HeaderWidget("Header 4"),
],
),
),
SliverList(
delegate: SliverChildListDelegate(
[
BodyWidget(Colors.blue),
BodyWidget(Colors.red),
BodyWidget(Colors.green),
BodyWidget(Colors.orange),
BodyWidget(Colors.blue),
BodyWidget(Colors.red),
],
),
),
SliverGrid(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 2),
delegate: SliverChildListDelegate(
[
BodyWidget(Colors.blue),
BodyWidget(Colors.green),
BodyWidget(Colors.yellow),
BodyWidget(Colors.orange),
BodyWidget(Colors.blue),
BodyWidget(Colors.red),
],
),
),
],
),
),
)
return new MaterialApp(
home: new Scaffold(
appBar: new AppBar(
title: new Text("Login / Signup"),
),
body: new Container(
child: new Center(
child: ListView(
//mainAxisAlignment: MainAxisAlignment.center,
scrollDirection: Axis.vertical,
children: <Widget>[
new TextField(
decoration: new InputDecoration(
hintText: "E M A I L A D D R E S S"
),
),
new Padding(padding: new EdgeInsets.all(15.00)),
new TextField(obscureText: true,
decoration: new InputDecoration(
hintText: "P A S S W O R D"
),
),
new Padding(padding: new EdgeInsets.all(15.00)),
new TextField(decoration: new InputDecoration(
hintText: "U S E R N A M E"
),),
new RaisedButton(onPressed: null,
child: new Text("SIGNUP"),),
new Padding(padding: new EdgeInsets.all(15.00)),
new RaisedButton(onPressed: null,
child: new Text("LOGIN"),),
new Padding(padding: new EdgeInsets.all(15.00)),
new ListView(scrollDirection: Axis.horizontal,
children: <Widget>[
new RaisedButton(onPressed: null,
child: new Text("Facebook"),),
new Padding(padding: new EdgeInsets.all(5.00)),
new RaisedButton(onPressed: null,
child: new Text("Google"),)
],)
],
),
),
margin: new EdgeInsets.all(15.00),
),
),
);
Also, you can try use CustomScrollView
CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
SliverList(
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
final OrderModel order = _orders[index];
return Container(
margin: const EdgeInsets.symmetric(
vertical: 8,
),
child: _buildOrderCard(order, size, context),
);
},
childCount: _orders.length,
),
),
SliverToBoxAdapter(
child: _buildPreloader(context),
),
],
);
Tip: _buildPreloader return CircularProgressIndicator or Text
In my case i want to show under ListView some widgets. Use Column does't work me, because widgets around ListView inside Column showing always "up" on the screen, like "position absolute"
Sorry for my bad english