Paypal payment gateway add flutter app with magento 2 web details username , password , signature Magento 2?

I have Magento 2 details username , password , signature ( Paypal payment gateway ). How to add Paypal payment gateway in flutter app with this ( Magento 2 Paypal ) details.

Already implement with clientId and secretKey in flutter app successfully but i received only Magento 2 details.

how can i do this thing with Magento Details ?

import 'package:flutter/material.dart';
import 'package:flutter_paypal/flutter_paypal.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Paypal',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Paypal Example'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Center(
          child: TextButton(
              onPressed: () => {
                Navigator.of(context).push(
                  MaterialPageRoute(
                    builder: (BuildContext context) => UsePaypal(
                        sandboxMode: true,
                        clientId:
                        "AW1TdvpSGbIM5iP4HJNI5TyTmwpY9Gv9dYw8_8yW5lYIbCqf326vrkrp0ce9TAqjEGMHiV3OqJM_aRT0",
                        secretKey:
                        "EHHtTDjnmTZATYBPiGzZC_AZUfMpMAzj2VZUeqlFUrRJA_C0pQNCxDccB5qoRQSEdcOnnKQhycuOWdP9",
                        returnURL: "https://samplesite.com/return",
                        cancelURL: "https://samplesite.com/cancel",
                        transactions: const [
                          {
                            "amount": {
                              "total": '100',

                              "currency": "USD",
                              "details": {
                                "tax":30,
                                "shipping": '50',
                                "shipping_discount": 10,
                                "discount":'10',
                                "subtotal": '40',
                              }
                            },
                            "description":
                            "The payment transaction description.",
                            // "payment_options": {
                            //   "allowed_payment_method":
                            //       "INSTANT_FUNDING_SOURCE"
                            // },
                            "item_list": {
                              "items": [
                                {
                                  "name": "A Gift Card",
                                  "quantity": 2,
                                  "price": '10',
                                  "currency": "USD"
                                },
                                {
                                  "name": "Push it bag",
                                  "quantity": 1,
                                  "price": '20',
                                  "currency": "USD"
                                }
                              ],

                              // shipping address is not required though
                              "shipping_address": {
                                "recipient_name": "Jane Foster",
                                "line1": "Travis County",
                                "line2": "",
                                "city": "Austin",
                                "country_code": "US",
                                "postal_code": "73301",
                                "phone": "+00000000",
                                "state": "Texas"
                              },
                            }
                          }
                        ],
                        note: "Contact us for any questions on your order.",
                        onSuccess: (Map params) async {
                          print("onSuccess: $params");
                        },
                        onError: (error) {
                          print("onError: $error");
                        },
                        onCancel: (params) {
                          print('cancelled: $params');
                        }),
                  ),
                )
              },
              child: const Text("Make Payment")),
        ));
  }
}

The API Username, Password, and Secret are used to authenticate with PayPal's classic APIs, which are about 20 years old.

Current APIs authenticate with a REST APP client ID and secret instead. So you should use that.

Forget about the classic API credentials, do not use them nor the classic APIs for any new integration.