listView and row view creation problems flutter - flutter

Question

I have my listView that works correctly without the Row code, but I need to place a textfield and a button under the last element of the ListView. both at the same height. that's why I thought about using Row. but if I try to write it under my listView and start the app, I don't see anything, not even the listView. as an error it is only reported to me:
The relevant error-causing widget was:
ListView file:///Users/apple/Desktop/Work%202021/toduba-merchant/lib/tabs/home_tab.dart:95:22
When the exception was thrown, this was the stack:
#0 RenderViewportBase._paintContents (package:flutter/src/rendering/viewport.dart:649:25)
#1 RenderViewportBase.paint (package:flutter/src/rendering/viewport.dart:641:7)
#2 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2322:7)
#3 PaintingContext._repaintCompositedChild (package:flutter/src/rendering/object.dart:140:11)
#4 PaintingContext.repaintCompositedChild (package:flutter/src/rendering/object.dart:100:5)
...
The following RenderObject was being processed when the exception was fired: RenderViewport#ba090
... needs compositing
... parentData: (can use size)
... constraints: BoxConstraints(w=375.0, h=474.9)
... layer: OffsetLayer#32030 DETACHED
... engine layer: Null#007db
... offset: Offset(0.0, 0.0)
... size: Size(375.0, 474.9)
... axisDirection: down
... crossAxisDirection: right
... offset: ScrollPositionWithSingleContext#d8a7b(offset: 0.0, range: null..null, viewport: 474.9, ScrollableState, BouncingScrollPhysics -> RangeMaintainingScrollPhysics, IdleScrollActivity#f75ff, ScrollDirection.idle)
... anchor: 0.0
RenderObject: RenderViewport#ba090
needs compositing
parentData: (can use size)
constraints: BoxConstraints(w=375.0, h=474.9)
layer: OffsetLayer#32030 DETACHED
engine layer: Null#007db
offset: Offset(0.0, 0.0)
size: Size(375.0, 474.9)
axisDirection: down
crossAxisDirection: right
offset: ScrollPositionWithSingleContext#d8a7b(offset: 0.0, range: null..null, viewport: 474.9, ScrollableState, BouncingScrollPhysics -> RangeMaintainingScrollPhysics, IdleScrollActivity#f75ff, ScrollDirection.idle)
anchor: 0.0
... center child: RenderSliverPadding#7222a relayoutBoundary=up1 NEEDS-PAINT
... needs compositing
... parentData: paintOffset=Offset(0.0, 0.0) (can use size)
... constraints: SliverConstraints(AxisDirection.down, GrowthDirection.forward, ScrollDirection.idle, scrollOffset: 0.0, remainingPaintExtent: 474.9, crossAxisExtent: 375.0, crossAxisDirection: AxisDirection.right, viewportMainAxisExtent: 474.9, remainingCacheExtent: 724.9, cacheOrigin: 0.0)
... geometry: null
... padding: EdgeInsets.all(20.0)
... textDirection: ltr
... child: RenderSliverList#9d74e relayoutBoundary=up2 NEEDS-PAINT
... needs compositing
... parentData: paintOffset=Offset(0.0, 0.0) (can use size)
... constraints: SliverConstraints(AxisDirection.down, GrowthDirection.forward, ScrollDirection.idle, scrollOffset: 0.0, remainingPaintExtent: 454.9, crossAxisExtent: 335.0, crossAxisDirection: AxisDirection.right, viewportMainAxisExtent: 474.9, remainingCacheExtent: 704.9, cacheOrigin: 0.0)
... geometry: null
... currently live children: 0 to 3
... child with index 0: RenderIndexedSemantics#3b488 relayoutBoundary=up3 NEEDS-PAINT
... needs compositing
... parentData: index=0; layoutOffset=0.0 (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... semantic boundary
... size: Size(335.0, 29.0)
... index: 0
... child: RenderRepaintBoundary#8cd41 relayoutBoundary=up4 NEEDS-PAINT
... needs compositing
... parentData: (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... size: Size(335.0, 29.0)
... usefulness ratio: no metrics collected yet (never painted)
... child with index 1: RenderIndexedSemantics#c3e1f relayoutBoundary=up3 NEEDS-PAINT
... needs compositing
... parentData: index=1; layoutOffset=29.0 (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... semantic boundary
... size: Size(335.0, 260.0)
... index: 1
... child: RenderRepaintBoundary#16c99 relayoutBoundary=up4 NEEDS-PAINT
... needs compositing
... parentData: (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... size: Size(335.0, 260.0)
... usefulness ratio: no metrics collected yet (never painted)
... child with index 2: RenderIndexedSemantics#967b1 relayoutBoundary=up3 NEEDS-PAINT
... needs compositing
... parentData: index=2; layoutOffset=289.0 (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... semantic boundary
... size: Size(335.0, 22.0)
... index: 2
... child: RenderRepaintBoundary#348b5 relayoutBoundary=up4 NEEDS-PAINT
... needs compositing
... parentData: (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... size: Size(335.0, 22.0)
... usefulness ratio: no metrics collected yet (never painted)
... child with index 3: RenderIndexedSemantics#047b6 relayoutBoundary=up3 NEEDS-PAINT
... needs compositing
... parentData: index=3; layoutOffset=311.0 (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... semantic boundary
... size: MISSING
... index: 3
... child: RenderRepaintBoundary#af13c relayoutBoundary=up4 NEEDS-PAINT
... needs compositing
... parentData: (can use size)
... constraints: BoxConstraints(w=335.0, 0.0<=h<=Infinity)
... size: MISSING
... usefulness ratio: no metrics collected yet (never painted)
return Container(
color: appColors.primaryColor,
child: ListView(
primary: false,
children: [
// TITOLO
Align(
alignment: Alignment.center,
child: Container(
child: Text(
localization.showQR,
style: Theme.of(context).primaryTextTheme.headline5.copyWith(
color: appColors.green,
fontWeight: FontWeight.bold,
),
),
),
),
Align(
alignment: Alignment.center,
child: Container(
child: qrCodeHolder
),
),
Align(
alignment: Alignment.center,
child: Container(
child: AutoSizeText(
localization.home_subLabel,
textAlign: TextAlign.center,
maxLines: 1,
style: Theme.of(context).primaryTextTheme.headline5.copyWith(
color: appColors.green,
fontWeight: FontWeight.bold,
),
),
),
),
Positioned(
//top: size.height * .02,
//right: size.width * .02,
child: Row(
children: [
TextField(
inputFormatters: [
new LengthLimitingTextInputFormatter(7),
],
decoration: InputDecoration(
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 18.0,
color: Colors.black,
),
),
IconButton(
icon: Image.asset("assets/images/send.png"),
onPressed: () => showDialog(context: context, builder: (_) => PaymentDialog()),
),
Text("dfjbsdifbsdf"),
]
),
),
],
padding: EdgeInsets.all(20.0),
),
);

Answer 1

You need to wrap your TextField in an Expanded widget or a container with limited width.
This is because the Row assumes it can take maximum width, and the TextField and TextFormField widget by default try to take the maximum width possible.
By putting them inside each other, you'll get the error you are having.
Use this for the TextField, inside a row, it must be wrapped in Expanded or Flexible.
Row(
children: [
Expanded(
child: TextField ()
)
])