Expanded() widget not working in listview - flutter

Question

I'm new to flutter. I'm trying to render a page whose body contains Listview with multiple widgets.
_buildOrderDetails widget in the listview is widget that is build with listview.builder() , remaining are normal widgets.
The problem is page is not being scrolled .
When the body Listview is changed to column and _buildOrderDetails is given as child to the Expanded, the listview is limited to some extent of the page height and being scrolled. But when input is focused the page is overflowed
Widget build(BuildContext context){
return ScopedModelDescendant<MainModel>(
builder: (BuildContext context, Widget child, MainModel model) {
return Scaffold(
appBar: AppBar(
title: Text('Order Details'),
actions: <Widget>[
IconButton(
onPressed: () {
model.addNewOrder();
},
icon: Icon(Icons.add),
),
BadgeIconButton(
itemCount: model.ordersCount,
badgeColor: Color.fromRGBO(37, 134, 16, 1.0),
badgeTextColor: Colors.white,
icon: Icon(Icons.shopping_cart, size: 30.0,),
onPressed: () {}
),
]
),
body: ListView(
children: [
Column(
children: [
_buildItemsTitle(),
Expanded(child: _buildOrderDetails(context, model)),
]
),
Card(
child: Column(
children:[
TextField(
decoration: InputDecoration(
labelText: 'Offer Code'
),
),
RaisedButton(
onPressed: (){},
child: Text('Apply'),
)
]
),
),
Card(child: _orderAmount(context, model),),
RaisedButton(
color: Theme.of(context).accentColor,
onPressed: (){},
child: Text('Checkout',
style: TextStyle(
fontSize: 20.0,
color: Colors.white
)
),
)
]
),);});}}

Answer 1

Maybe it can help someone in the future, but the trick seems to be: use ListView + LimitedBox(maxHeight) + Column ...
ListView(
padding: EdgeInsets.zero,
shrinkWrap: true,
children: [
FocusTraversalGroup(
child: Form(
key: _formKey,
child: LimitedBox(
maxHeight: MediaQuery.of(context).size.height,
child: Column(
// mainAxisSize: MainAxisSize.min,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Spacer(flex: 30), // Or Expanded
// More Widgets...
Spacer(flex: 70), // Or Expanded
// ....

Answer 2

Try not to use expanded on growing items. If you want to cover a percentage/fractional height wrap the height with a fixed height or the full height with a container that includes box contstains, then proceed to have expanded or fixed height children. also helpful is the FracionalBox
In the example you showed there is no need for expanded, the children inside will give a content height and the SingleChildScrollView will automaticly handle scrolling based on children.
Widget build(BuildContext context) {
return ScopedModelDescendant<MainModel>(
builder: (BuildContext context, Widget child, MainModel model) {
return Scaffold(
appBar: AppBar(title: Text('Order Details'), actions: <Widget>[
IconButton(
onPressed: () {
model.addNewOrder();
},
icon: Icon(Icons.add),
),
BadgeIconButton(
itemCount: model.ordersCount,
badgeColor: Color.fromRGBO(37, 134, 16, 1.0),
badgeTextColor: Colors.white,
icon: Icon(
Icons.shopping_cart,
size: 30.0,
),
onPressed: () {}),
]),
body: SingleChildScrollView(
child: Column(
children: <Widget>[
Column(children: [
_buildItemsTitle(),
Container(child: _buildOrderDetails(context, model)),
]),
Card(
child: Column(children: [
TextField(
decoration: InputDecoration(labelText: 'Offer Code'),
),
RaisedButton(
onPressed: () {},
child: Text('Apply'),
)
]),
),
Card(
child: _orderAmount(context, model),
),
RaisedButton(
color: Theme.of(context).accentColor,
onPressed: () {},
child: Text('Checkout',
style: TextStyle(fontSize: 20.0, color: Colors.white)),
),
],
),
),
);
});
}