import 'package:flutter/material.dart'; class MockPaymentProvider with ChangeNotifier { double _amount = 10.0; bool _payerCoversFee = true; double get amount => _amount; bool get payerCoversFee => _payerCoversFee; double get fee => _amount * 0.05; double get total => payerCoversFee ? (_amount + fee) : _amount; double get recipientGets => payerCoversFee ? _amount : (_amount - fee); void setAmount(double value) { _amount = value; notifyListeners(); } void setPayerCoversFee(bool value) { _payerCoversFee = value; notifyListeners(); } }