class LayoutDemoextends StatelessWidget {
@override
Widgetbuild(BuildContext context) {
return new Scaffold(
appBar:new AppBar(
title: new Text ( 'ConstrainedBox defined width and height exemplary'),
),
body:new ConstrainedBox(
constraints:const BoxConstraints(
minWidth:250.0,
minHeight:150.0,
maxWidth:320.0,
maxHeight:220.0,
),
child:new Container(
width:300.0,
height:300.0,
color: Colors.green,
),
),
);
}
}