Braintree 支付插件在 Flutter 中不起作用

Question

我在我的 flutter 电子商务应用程序中使用了 Braintree 支付插件。 我必须启用 PayPal 这就是我使用 Braintree 插件的原因。 但我很困惑如何将此插件与服务器集成。 插件中没有提及。 此外，我集成了插件，但是这个插件在输入卡时出错，它被声明为无效。 而且我也对客户端随机数感到困惑，因为它是从服务器端生成的。 这是我的插件代码

导入“包：颤振/material.dart”； 导入“包：braintree_payment/braintree_payment.dart”；

 void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
  debugShowCheckedModeBanner: false,
  title: 'Barintree payment',
  theme: ThemeData(primaryColor: Colors.teal),
  home: Pay(),
);
}
}

class Pay extends StatefulWidget {
@override
_PayState createState() => _PayState();
}

class _PayState extends State<Pay> {
String clientNonce =
  "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";

payNow() async {
BraintreePayment braintreePayment = new BraintreePayment();
var data = await braintreePayment.showDropIn(
    nonce: clientNonce, amount: "2.0", enableGooglePay: true);
print("Response of the payment $data");
}

@override
Widget build(BuildContext context) {
return Scaffold(
  appBar: AppBar(
    title: Text("Pay Now"),
  ),
  body: Center(
    child: FlatButton(
      onPressed: payNow,
      color: Colors.teal,
      child: Text(
        "Pay Now",
        style: TextStyle(color: Colors.white),
      ),
    ),
  ),
);
}
}