Mixing columns and rows resolving in an error - dart

Question

I'm trying to create a form for my app containing two columns inside a row. Should look something like this:
But when I run this code:
#override
Widget build(BuildContext context) {
return /*new Padding (
padding: const EdgeInsets.all(15.0),
child: */new ListView (
//mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[new Row (children: <Widget>[
// Goal + Amount
new ListTile (
title: new Column (
mainAxisSize: MainAxisSize.min,
children: <Widget>[new Expanded(child: new TextField(
controller: widget._NameController,
style: new TextStyle (
fontSize: 20.0,
color: Colors.black,
),
decoration: new InputDecoration(
labelText: 'Name'
),
)), new Expanded(child:
new FlatButton(
onPressed: _showDatePicker,
child: new Text(
PARTIAL_DATE_FORMAT.format(_pickedDate)),
)),
]
)
),
// Goal Deadline
new ListTile (
title: new Column (
mainAxisSize: MainAxisSize.min,
children: <Widget>[new Expanded(child: new ListTile (
title: new TextField(
//controller: widget._TextController,,
style: new TextStyle (
fontSize: 20.0,
color: Colors.black
),
decoration: new InputDecoration(
labelText: 'Amount'
),
)
)), new Expanded(child:
new FlatButton(
onPressed: _showTimePicker,
child: new Text(_pickedTime.format(context)),
)),
]
)
),
]),
// Goal Description
new ListTile (
title: new TextField(
controller: widget._DescriptionController,
style: new TextStyle (
fontSize: 20.0,
color: Colors.black
),
decoration: new InputDecoration(
labelText: 'Description'
),
)
),
]
);
}
It resolves in this error:
I/flutter ( 2837): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter ( 2837): The following assertion was thrown during performLayout():
I/flutter ( 2837): RenderFlex children have non-zero flex but incoming width constraints are unbounded.
I/flutter ( 2837): When a row is in a parent that does not provide a finite width constraint, for example if it is in a
I/flutter ( 2837): horizontal scrollable, it will try to shrink-wrap its children along the horizontal axis. Setting a
I/flutter ( 2837): flex on a child (e.g. using Expanded) indicates that the child is to expand to fill the remaining
I/flutter ( 2837): space in the horizontal direction.
I/flutter ( 2837): These two directives are mutually exclusive. If a parent is to shrink-wrap its child, the child
I/flutter ( 2837): cannot simultaneously expand to fit its parent.
I/flutter ( 2837): Consider setting mainAxisSize to MainAxisSize.min and using FlexFit.loose fits for the flexible
I/flutter ( 2837): children (using Flexible rather than Expanded). This will allow the flexible children to size
I/flutter ( 2837): themselves to less than the infinite remaining space they would otherwise be forced to take, and
I/flutter ( 2837): then will cause the RenderFlex to shrink-wrap the children rather than expanding to fit the maximum
I/flutter ( 2837): constraints provided by the parent.
I/flutter ( 2837): The affected RenderFlex is:
I/flutter ( 2837): RenderFlex#770e0 relayoutBoundary=up8 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): The creator information is set to:
I/flutter ( 2837): Row ← Padding ← ConstrainedBox ← Container ← Listener ← _GestureSemantics ← RawGestureDetector ←
I/flutter ( 2837): GestureDetector ← InkWell ← ListTile ← Row ← RepaintBoundary-[<0>] ← ⋯
I/flutter ( 2837): The nearest ancestor providing an unbounded width constraint is:
I/flutter ( 2837): RenderFlex#47431 relayoutBoundary=up3 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): creator: Row ← RepaintBoundary-[<0>] ← NotificationListener<KeepAliveNotification> ← KeepAlive ←
I/flutter ( 2837): AutomaticKeepAlive ← SliverList ← Viewport ← _ScrollableScope ← IgnorePointer-[GlobalKey#60f18] ←
I/flutter ( 2837): Listener ← _GestureSemantics ←
I/flutter ( 2837): RawGestureDetector-[LabeledGlobalKey<RawGestureDetectorState>#f4728] ← ⋯
I/flutter ( 2837): parentData: <none> (can use size)
I/flutter ( 2837): constraints: BoxConstraints(w=381.4, 0.0<=h<=Infinity)
I/flutter ( 2837): size: MISSING
I/flutter ( 2837): direction: horizontal
I/flutter ( 2837): mainAxisAlignment: start
I/flutter ( 2837): mainAxisSize: max
I/flutter ( 2837): crossAxisAlignment: center
I/flutter ( 2837): textDirection: ltr
I/flutter ( 2837): verticalDirection: downSee also: https://flutter.io/layout/
I/flutter ( 2837): If this message did not help you determine the problem, consider using debugDumpRenderTree():
I/flutter ( 2837): https://flutter.io/debugging/#rendering-layer
I/flutter ( 2837): http://docs.flutter.io/flutter/rendering/debugDumpRenderTree.html
I/flutter ( 2837): If none of the above helps enough to fix this problem, please don't hesitate to file a bug:
I/flutter ( 2837): https://github.com/flutter/flutter/issues/new
I/flutter ( 2837): When the exception was thrown, this was the stack:
I/flutter ( 2837): #0 RenderFlex.performLayout.<anonymous closure> (package:flutter/src/rendering/flex.dart:690:11)
I/flutter ( 2837): #1 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:711:10)
I/flutter ( 2837): #2 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #3 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:197:11)
I/flutter ( 2837): #4 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #5 RenderConstrainedBox.performLayout (package:flutter/src/rendering/proxy_box.dart:257:13)
I/flutter ( 2837): #6 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #7 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #8 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #9 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #10 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #11 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:737:15)
I/flutter ( 2837): #12 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #13 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #14 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #15 RenderSliverList.performLayout (package:flutter/src/rendering/sliver_list.dart:164:27)
I/flutter ( 2837): #16 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #17 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:286:13)
I/flutter ( 2837): #18 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:979:12)
I/flutter ( 2837): #19 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:903:20)
I/flutter ( 2837): #20 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #21 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #22 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #23 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #24 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #25 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #26 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #27 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #28 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #29 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #30 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #31 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #32 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #33 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:197:11)
I/flutter ( 2837): #34 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #35 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:124:11)
I/flutter ( 2837): #36 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:91:7)
I/flutter ( 2837): #37 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:194:7)
I/flutter ( 2837): #38 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:338:14)
I/flutter ( 2837): #39 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #40 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #41 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #42 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #43 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1005:24)
I/flutter ( 2837): #44 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #45 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #46 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #47 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #48 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #49 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #50 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #51 RenderOffstage.performLayout (package:flutter/src/rendering/proxy_box.dart:2747:14)
I/flutter ( 2837): #52 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #53 RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:107:13)
I/flutter ( 2837): #54 RenderObject.layout (package:flutter/src/rendering/object.dart:1962:7)
I/flutter ( 2837): #55 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:466:15)
I/flutter ( 2837): #56 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1837:7)
I/flutter ( 2837): #57 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:1126:18)
I/flutter ( 2837): #58 BindingBase&SchedulerBinding&GestureBinding&ServicesBinding&RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:262
:19)
I/flutter ( 2837): #59 BindingBase&SchedulerBinding&GestureBinding&ServicesBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/bin
ding.dart:581:22)
I/flutter ( 2837): #60 BindingBase&SchedulerBinding&GestureBinding&ServicesBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rende
ring/binding.dart:200:5)
I/flutter ( 2837): #61 BindingBase&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:713:15)
I/flutter ( 2837): #62 BindingBase&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:649:9)
I/flutter ( 2837): #63 _invoke (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:91)
I/flutter ( 2837): #64 _drawFrame (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:80)
I/flutter ( 2837): The following RenderObject was being processed when the exception was fired:
I/flutter ( 2837): RenderFlex#770e0 relayoutBoundary=up8 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): creator: Row ← Padding ← ConstrainedBox ← Container ← Listener ← _GestureSemantics ←
I/flutter ( 2837): RawGestureDetector ← GestureDetector ← InkWell ← ListTile ← Row ← RepaintBoundary-[<0>] ← ⋯
I/flutter ( 2837): parentData: offset=Offset(0.0, 0.0) (can use size)
I/flutter ( 2837): constraints: BoxConstraints(0.0<=w<=Infinity, h=56.0)
I/flutter ( 2837): size: MISSING
I/flutter ( 2837): direction: horizontal
I/flutter ( 2837): mainAxisAlignment: start
I/flutter ( 2837): mainAxisSize: max
I/flutter ( 2837): crossAxisAlignment: center
I/flutter ( 2837): textDirection: ltr
I/flutter ( 2837): verticalDirection: down
I/flutter ( 2837): This RenderObject had the following descendants (showing up to depth 5):
I/flutter ( 2837): RenderFlex#5610b NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderSemanticsGestureHandler#6d25d NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderPointerListener#4eb7b NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderConstrainedBox#3d105 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderStack#f6a43 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderConstrainedBox#13bd4 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderSemanticsGestureHandler#905d0 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderPointerListener#ec2c3 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): RenderPadding#2b663 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 2837): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/box.dart': Failed assertion: line 1433 pos 12: 'hasSize': is not true.
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/box.dart': Failed assertion: line 1433 pos 12: 'hasSize': is not true.
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/box.dart': Failed assertion: line 1433 pos 12: 'hasSize': is not true.
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/box.dart': Failed assertion: line 1433 pos 12: 'hasSize': is not true.
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/box.dart': Failed assertion: line 1433 pos 12: 'hasSize': is not true.
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/box.dart': Failed assertion: line 1433 pos 12: 'hasSize': is not true.
I/flutter ( 2837): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 458 pos 12: 'child.hasSiz
e': is not true.
I/flutter ( 2837): Another exception was thrown: NoSuchMethodError: The method 'debugAssertIsValid' was called on null.
I/flutter ( 2837): Another exception was thrown: NoSuchMethodError: The getter 'visible' was called on null.
I'm very new to flutter and having a lot of trouble working with it due to the lack of information on the internet about that.

Answer 1

I have a created a simple example to show you how you can approach building the desired layout, the usage of ListTile in your code is really confusing and should not be used in this way. The information you provided are not clear enough on what the different elements in your layout represents. That is why I am filling them with a Container, you should be able to provide any widget as child of the container to get started.
import "package:flutter/material.dart";
class Layout extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(),
body: new Padding(
padding: const EdgeInsets.all(30.0),
child:new Column(
children: <Widget>[
new Row(
children: <Widget>[
new SizedBox(
height: 30.0 ,
width: 200.0,
child: new Container(color: Colors.redAccent,),
),
new Container(width: 40.0,),
new SizedBox(
height: 30.0,
width: 50.0,
child: new Container(color:Colors.amberAccent),
)
],
),
new Container(height: 30.0,),
new Row(
children: <Widget>[
new SizedBox(
height: 40.0 ,
width: 100.0,
child: new Container(color: Colors.redAccent,),
),
new Container(width: 140.0,),
new SizedBox(
height: 40.0,
width: 50.0,
child: new Container(color:Colors.amberAccent),
)
],
),
new Container(height: 30.0,),
new Container(color: Colors.tealAccent,width: 290.0,height: 320.0,)
],
),),
);
}
}
Update
I believe you are trying to do similar layout to the following one, the real problem with your code is using ListTile, ListTiles are used to store minimal information (like contact lists for example), and should not be used to contain nested widgets because they are limited in size.
Secondly, I was only doing the previous example as a demonstration, however, yes you are correct about the fixed size problems. In order to avoid this you can use check FractionallySizedBox, or like I did at the very end of the ListView here, using MediaQuery.of(context).size.height*0.3 gave me a Container with height that is 30% of the total screen height.
import "package:flutter/material.dart";
class Layout extends StatefulWidget {
#override
_LayoutState createState() => new _LayoutState();
}
class _LayoutState extends State<Layout> {
String time = "Set Time";
String date = "Set Date ";
String dropDownString;
_showDate(BuildContext context) async {
var datePicked = await showDatePicker(context: context,
initialDate: new DateTime.now(),
firstDate: new DateTime(2010, 2),
lastDate: new DateTime(2018, 1));
setState(() {
date = "${datePicked.month}/${datePicked.day}/${datePicked.year}";
});
}
_showTime(BuildContext context) async {
var timePicked = await showTimePicker(
context: context, initialTime: new TimeOfDay.now());
setState(() {
time = "${timePicked.hour}:${timePicked.minute} ";
});
}
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(title: new Text("Layout Example"),),
body: new Padding(padding: const EdgeInsets.all(20.0),
child: new ListView(
//shrinkWrap: true,
children: <Widget>[
new Row(
children: <Widget>[
new Expanded(child: new TextField()),
new Expanded(child: new FlatButton(
onPressed: () => _showDate(context),
child: new Text(date))),
],
),
new Row(
children: <Widget>[
new Expanded(child: new TextField()),
new Expanded(child: new FlatButton(
onPressed: () => _showTime(context),
child: new Text(time))),
],),
new TextField(
maxLines: 5,
),
new Container(
height: MediaQuery.of(context).size.height*0.3,
color: Colors.tealAccent,
)
],
),
),
);
}
}