how to prevent to change colour while list view scroll - flutter

Question

I have created a demo
I have set colour as random for each container of list view, so it changes colours whenever I scroll ,
I want to prevent changing colour while scrolling,
Like if first container colour is red then it should b not changed until I restart app,
I placed print statement inside build method...but it showing only once, than why container's colour get changed,
if it rebuilds, it should execute print statement more than one time
#override
Widget build(BuildContext context) {
return Scaffold(
body: ListView.builder(
itemCount: 10,
itemBuilder: (context,index){
return Container(
height: 200,
color: Color.fromRGBO(Random().nextInt(255), Random().nextInt(255), Random().nextInt(255), 1),
);
}),
);
}

Answer 1

In ListView.builder items won't be alive for performance matter, every time you scroll, it build those item. try this:
#override
Widget build(BuildContext context) {
var colorList = List<Color>.generate(10, (index) => Color.fromRGBO(Random().nextInt(255), Random().nextInt(255), Random().nextInt(255), 1)).toList();
return Scaffold(
body: ListView.builder(
itemCount: colorList.length,
itemBuilder: (context,index){
return Container(
height: 200,
color: colorList[index],
);
}),
);
}