Updating part of a stateful widget - flutter

Question

i'm very new to Flutter.
I have a stateful widget. Every time i click a counter, the whole build function runs and the results are updated.
But is there a way to make it a stateless widget and update only the relevant part somehow so i could avoid rebuilding the screen?
I have a stateful widget. Every time i click a counter, the whole build function runs and the results are updated.
But is there a way to make it a stateless widget and update only the relevant part somehow so i could avoid rebuilding the screen?
import 'package:flutter/material.dart';
void main() {
runApp(MaterialApp(
home:Home(),
));
}
class Home extends StatefulWidget {
#override
_HomeState createState() => _HomeState();
}
class _HomeState extends State {
int long = 0;
void increaseCounter(){
setState(() {
long++;
});
}
void decreaseCounter(){
if(long > 0) {
setState(() {
long--;
});
}
}
Text numberOfDeliveries(){
return Text(
'$long deliveries today',
style: TextStyle(
color:Colors.white,
fontSize: 24.0,
),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title:Text('Deliveries'),
backgroundColor: Colors.green,
),
body: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Expanded(
child: Container(
color: Colors.blue,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Expanded(
child:Padding(
padding: const EdgeInsets.symmetric(vertical: 32.0, horizontal: 0.0),
child: Text(
'Long',
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 32.0,
color: Colors.white,
),
),
),
),
Expanded(
child:
// is it possible to update this without running the whole build again?
numberOfDeliveries(),
),
Expanded(
child: Row(
children: [
Expanded(
child: Container(
padding: EdgeInsets.symmetric(vertical: 32.0, horizontal: 0.0),
color:Colors.blue[100],
child: FlatButton(
onPressed: (){
decreaseCounter();
},
child: Text('-'),
),
),
),
Expanded(
child: Container(
padding: EdgeInsets.symmetric(vertical: 32.0, horizontal: 0.0),
color:Colors.blue[500],
),
),
Expanded(
child: Container(
padding: EdgeInsets.symmetric(vertical: 32.0, horizontal: 0.0),
color:Colors.blue[900],
child: FlatButton(
onPressed: (){
increaseCounter();
},
child: Text('+'),
),
),
),
],
),
),
],
),
),
),
Expanded(
child: Container(
color: Colors.blue[800],
child: Row(
children: [
Text('Bottom'),
],
),
),
),
],
),
);
}
}