Flexible scrolling content on overflow - flutter

Question

I want to have a container with a flexible body (red) height and a fixed button height (gray).
The complete container should be as small as possible and have a max height.
If the content is overflowing the max height it should be scrollable.
I'm new to flutter, so I have no idea how to achieve this.
I tried it with a ConstraintBox with maxHeight, but then the whole container is bigger then it have to be, when the content is small.
return Container(
child: Column(
children: [
ConstrainedBox(
maxHeight: 400
child: //SomeWidget that could overflow
),
Container(
height: 150,
child: Center(
child: TextButton(child: Text('OK'))
),
)
],
),
);
Can someone help?

Answer 1

You can set constraints of your Container. Also you can use Flexible and SingleChildScrollView
Container(
constraints: BoxConstraints(
maxHeight: 300,
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Flexible(
child: SingleChildScrollView(
child: Column(
children: [
//SomeWidget that could overflow
],
),
)),
Container(
color: Colors.amber,
height: 150,
child:
Center(child: TextButton(onPressed: () {}, child: Text('OK'))),
)
],
),
)

Answer 2

I've achieved it now, with that code:
Container(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Flexible(
child: SingleChildScrollView(
child: //SomeWidget that could overflow
),
),
Container(
alignment: Alignment.bottomCenter,
child: TextButton(
child: Text('OK')
)
)
]
)
)

Answer 3

According to your UI i think this one will be perfect, and let me know if you need any changes. use constraints to change size.
final widgets = List.generate(
12,
(index) => Container(
height: 100,
color: index % 2 == 0 ? Colors.cyanAccent : Colors.greenAccent,
child: Text("item $index"),
),
);
#override
Widget build(BuildContext context) {
return Scaffold(
body: LayoutBuilder(
builder: (context, constraints) => Stack(
children: [
Align(
alignment: Alignment.topCenter,
child: SizedBox(
///* used 90% of screen for items
height: constraints.maxHeight * .9,
child: ListView(
children: [
Center(child: Text("inside listView")),
///your widgets
...widgets,
Center(child: Text("End of listView")),
],
),
),
),
Positioned(
bottom: 0,
left: 0,
right: 0,
child: Container(
color: Colors.grey.withOpacity(.3),
///* used 10% of screen for Button
height: constraints.maxHeight * .1,
child: Center(
child: TextButton(
child: Text('OK'),
onPressed: () {},
),
),
),
),
],
),
),
);
}