donate_buttonrow

import 'package:flutter/material.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: donateMain(),
        ),
      ),
    );
  }
}

class donateMain extends StatefulWidget {
  const donateMain({Key? key}) : super(key: key);

  @override
  State<donateMain> createState() => _donateMainState();
}

class _donateMainState extends State<donateMain> {
  int currentAmount = 0;    //i want to call currentAmount

  void _setAmount(int amount) {
    setState(() {
      currentAmount = amount;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text('$currentAmount'),
      ),
      body: ButtonsRow(
        amount: currentAmount,
        onSetAmount: _setAmount,
      ),
    );
  }
}

class ButtonsRow extends StatelessWidget {
  const ButtonsRow({
    Key? key,
    required this.amount,
    required this.onSetAmount,
  }) : super(key: key);

  final void Function(int) onSetAmount;
  final int amount;
  
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: SingleChildScrollView(
        child: Column(children: [
          GestureDetector(
            onTap: () {
              onSetAmount(100);
            },
            child: Container(
            child: Center(
              child: Text(
                "€$amount",   // this is where i want to access current amount
                style: TextStyle(
                  fontSize: 35, color: Colors.black, fontWeight: FontWeight.bold),
                textAlign: TextAlign.center,
              ),
            )
           )
          )
        ]
       )
      )
    );
  }
}