如何在Flutter中添加XML Google Pay按钮

dependencies:
  flutter:
    sdk: flutter
  google_pay: ^版本号

import 'package:google_pay/google_pay.dart';

ElevatedButton(
  onPressed: () {
    // 在这里处理Google Pay按钮的点击事件
    _handleGooglePayButton();
  },
  child: Text('Google Pay'),
)

void _handleGooglePayButton() async {
  // 检查设备是否支持Google Pay
  bool isGooglePayAvailable = await GooglePay.isGooglePayAvailable();

  if (isGooglePayAvailable) {
    // 创建Google Pay按钮
    GooglePayButton googlePayButton = GooglePayButton(
      paymentConfigurationAsset: 'assets/google_pay.json',
      paymentItems: [
        PaymentItem(
          label: '商品名称',
          price: '10.00',
          currencyCode: 'USD',
        ),
      ],
      style: GooglePayButtonStyle.black,
      type: GooglePayButtonType.pay,
      margin: const EdgeInsets.only(top: 15.0),
      onPaymentResult: (PaymentResult paymentResult) {
        // 处理支付结果
        _handlePaymentResult(paymentResult);
      },
    );

    // 显示Google Pay按钮
    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('Google Pay'),
          content: googlePayButton,
        );
      },
    );
  } else {
    // 设备不支持Google Pay
    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('Google Pay'),
          content: Text('设备不支持Google Pay'),
        );
      },
    );
  }
}

void _handlePaymentResult(PaymentResult paymentResult) {
  // 处理支付结果
  if (paymentResult.status == PaymentStatus.success) {
    // 支付成功
    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('支付结果'),
          content: Text('支付成功'),
        );
      },
    );
  } else {
    // 支付失败
    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('支付结果'),
          content: Text('支付失败'),
        );
      },
    );
  }
}