feat: add possibility to create deffered payment for payment sheet

example/lib/screens/payment_sheet/payment_sheet_deffered_screen.dart

@@ -0,0 +1,178 @@
+import 'dart:convert';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_stripe/flutter_stripe.dart';
+import 'package:http/http.dart' as http;
+import 'package:stripe_example/config.dart';
+import 'package:stripe_example/screens/payment_sheet/payment_sheet_screen_custom_flow.dart';
+import 'package:stripe_example/widgets/example_scaffold.dart';
+import 'package:stripe_example/widgets/loading_button.dart';
+
+class PaymentSheetDefferedScreen extends StatefulWidget {
+  @override
+  _PaymentSheetScreenState createState() => _PaymentSheetScreenState();
+}
+
+class _PaymentSheetScreenState extends State<PaymentSheetDefferedScreen> {
+  int step = 0;
+
+  @override
+  Widget build(BuildContext context) {
+    return ExampleScaffold(
+      title: 'Payment Sheet',
+      tags: ['Single Step'],
+      children: [
+        Stepper(
+          controlsBuilder: emptyControlBuilder,
+          currentStep: step,
+          steps: [
+            Step(
+              title: Text('Init payment'),
+              content: LoadingButton(
+                onPressed: initPaymentSheet,
+                text: 'Init payment sheet',
+              ),
+            ),
+            Step(
+              title: Text('Confirm payment'),
+              content: LoadingButton(
+                onPressed: confirmPayment,
+                text: 'Pay now',
+              ),
+            ),
+          ],
+        ),
+      ],
+    );
+  }
+
+  Future<void> _createIntentAndConfirmToUser() async {
+    final url = Uri.parse('$kApiUrl/payment-sheet');
+    final response = await http.post(
+      url,
+      headers: {
+        'Content-Type': 'application/json',
+      },
+      body: json.encode({
+        'a': 'a',
+      }),
+    );
+    final body = json.decode(response.body);
+    if (body['error'] != null) {
+      throw Exception(body['error']);
+    }
+
+    await Stripe.instance.intentCreationCallback(
+        IntentCreationCallbackParams(clientSecret: body['paymentIntent']));
+  }
+
+  Future<void> initPaymentSheet() async {
+    try {
+      // // 1. create payment intent on the server
+      // final data = await _createTestPaymentSheet();
+
+      // create some billingdetails
+      final billingDetails = BillingDetails(
+        name: 'Flutter Stripe',
+        email: '[email protected]',
+        phone: '+48888000888',
+        address: Address(
+          city: 'Houston',
+          country: 'US',
+          line1: '1459  Circle Drive',
+          line2: '',
+          state: 'Texas',
+          postalCode: '77063',
+        ),
+      ); // mocked data for tests
+
+      // 2. initialize the payment sheet
+      await Stripe.instance.initPaymentSheet(
+        paymentSheetParameters: SetupPaymentSheetParameters(
+          // Main params
+          merchantDisplayName: 'Flutter Stripe Store Demo',
+          intentConfiguration: IntentConfiguration(
+              mode: IntentMode(
+                currencyCode: 'EUR',
+                amount: 1500,
+              ),
+              intentCreationCallback: (method, saveFuture) {
+                _createIntentAndConfirmToUser();
+              }),
+
+          // Extra params
+          primaryButtonLabel: 'Pay now',
+          applePay: PaymentSheetApplePay(
+            merchantCountryCode: 'DE',
+          ),
+          googlePay: PaymentSheetGooglePay(
+            merchantCountryCode: 'DE',
+            testEnv: true,
+          ),
+          style: ThemeMode.dark,
+          appearance: PaymentSheetAppearance(
+            colors: PaymentSheetAppearanceColors(
+              background: Colors.lightBlue,
+              primary: Colors.blue,
+              componentBorder: Colors.red,
+            ),
+            shapes: PaymentSheetShape(
+              borderWidth: 4,
+              shadow: PaymentSheetShadowParams(color: Colors.red),
+            ),
+            primaryButton: PaymentSheetPrimaryButtonAppearance(
+              shapes: PaymentSheetPrimaryButtonShape(blurRadius: 8),
+              colors: PaymentSheetPrimaryButtonTheme(
+                light: PaymentSheetPrimaryButtonThemeColors(
+                  background: Color.fromARGB(255, 231, 235, 30),
+                  text: Color.fromARGB(255, 235, 92, 30),
+                  border: Color.fromARGB(255, 235, 92, 30),
+                ),
+              ),
+            ),
+          ),
+          billingDetails: billingDetails,
+        ),
+      );
+      setState(() {
+        step = 1;
+      });
+    } catch (e) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text('Error: $e')),
+      );
+      rethrow;
+    }
+  }
+
+  Future<void> confirmPayment() async {
+    try {
+      // 3. display the payment sheet.
+      await Stripe.instance.presentPaymentSheet();
+
+      setState(() {
+        step = 0;
+      });
+
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text('Payment succesfully completed'),
+        ),
+      );
+    } on Exception catch (e) {
+      if (e is StripeException) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(
+            content: Text('Error from Stripe: ${e.error.localizedMessage}'),
+          ),
+        );
+      } else {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(
+            content: Text('Unforeseen error: ${e}'),
+          ),
+        );
+      }
+    }
+  }
+}

example/lib/screens/screens.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:stripe_example/screens/checkout/checkout_screen.dart';
 import 'package:stripe_example/screens/payment_sheet/payment_element/payment_element.dart';
+import 'package:stripe_example/screens/payment_sheet/payment_sheet_deffered_screen.dart';
 import 'package:stripe_example/screens/payment_sheet/payment_sheet_screen.dart';
 import 'package:stripe_example/screens/payment_sheet/payment_sheet_screen_custom_flow.dart';
 import 'package:stripe_example/screens/regional_payment_methods/ali_pay_screen.dart';
@@ -101,6 +102,11 @@ class Example extends StatelessWidget {
           builder: (context) => PaymentSheetScreen(),
           platformsSupported: [DevicePlatform.android, DevicePlatform.ios],
         ),
+        Example(
+          title: 'Single Step (deffered payment)',
+          builder: (context) => PaymentSheetDefferedScreen(),
+          platformsSupported: [DevicePlatform.android, DevicePlatform.ios],
+        ),
         Example(
           title: 'Custom Flow',
           builder: (context) => PaymentSheetScreenWithCustomFlow(),

packages/stripe/lib/src/stripe.dart

@@ -444,6 +444,13 @@ class Stripe {
     return await _platform.presentPaymentSheet(options: options);
   }
 
+  /// Method used to confirm to the user that the intent is created successfull
+  /// or not successfull when using a defferred payment method.
+  Future<void> intentCreationCallback(IntentCreationCallbackParams params) async {
+    await _awaitForSettings();
+    return await _platform.intentCreationCallback(params);
+  }
+
   /// Call this method when the user logs out from your app.
   ///
   /// This will ensure that any persisted authentication state in the

packages/stripe_platform_interface/lib/src/method_channel_stripe.dart

@@ -5,6 +5,7 @@ import 'package:stripe_platform_interface/src/models/ach_params.dart';
 import 'package:stripe_platform_interface/src/models/create_token_data.dart';
 import 'package:stripe_platform_interface/src/models/financial_connections.dart';
 import 'package:stripe_platform_interface/src/models/google_pay.dart';
+import 'package:stripe_platform_interface/src/models/intent_creation_callback_params.dart';
 import 'package:stripe_platform_interface/src/models/platform_pay.dart';
 import 'package:stripe_platform_interface/src/models/wallet.dart';
 import 'package:stripe_platform_interface/src/result_parser.dart';
@@ -32,9 +33,7 @@ class MethodChannelStripe extends StripePlatform {
     required bool platformIsAndroid,
   })  : _methodChannel = methodChannel,
         _platformIsAndroid = platformIsAndroid,
-        _platformIsIos = platformIsIos {
-    _init();
-  }
+        _platformIsIos = platformIsIos;
 
   final MethodChannel _methodChannel;
   final bool _platformIsIos;
@@ -58,9 +57,11 @@ class MethodChannelStripe extends StripePlatform {
       'urlScheme': urlScheme,
       'setReturnUrlSchemeOnAndroid': setReturnUrlSchemeOnAndroid,
     });
-  }
 
-  void _init() {}
+    _methodChannel.setMethodCallHandler((call) async {
+      print('foo ${call.method}');
+    });
+  }
 
   @override
   Future<PaymentMethod> createPaymentMethod(
@@ -509,6 +510,15 @@ class MethodChannelStripe extends StripePlatform {
       orderDetails.toJson(),
     );
   }
+
+  @override
+  Future<void> intentCreationCallback(
+      IntentCreationCallbackParams params) async {
+    await _methodChannel.invokeMethod(
+      'intentCreationCallback',
+      {'params': params.toJson()},
+    );
+  }
 }
 
 class MethodChannelStripeFactory {

packages/stripe_platform_interface/lib/src/models/capture_method.dart

@@ -0,0 +1,13 @@
+/// Defines how the money will be captured from the customer's account.
+// ignore_for_file: constant_identifier_names
+
+enum CaptureMethod {
+  /// Reserve the funds but the customer has to authorize the payment.
+  Manual,
+
+  /// Funds are automatically captured by stripe
+  Automatic,
+
+  /// The payment was collected outside of Stripe.
+  AutomaticAsync,
+}

packages/stripe_platform_interface/lib/src/models/intent_creation_callback_params.dart

@@ -0,0 +1,20 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:stripe_platform_interface/src/models/errors.dart';
+
+part 'intent_creation_callback_params.freezed.dart';
+part 'intent_creation_callback_params.g.dart';
+
+@freezed
+class IntentCreationCallbackParams with _$IntentCreationCallbackParams {
+  @JsonSerializable(explicitToJson: true)
+  const factory IntentCreationCallbackParams({
+    /// Client secret of the payment intent or setup intent.
+    String? clientSecret,
+
+    /// Error that occurred during the creation of the payment intent or setup intent.
+    StripeException? error,
+  }) = _IntentCreationCallbackParams;
+
+  factory IntentCreationCallbackParams.fromJson(Map<String, dynamic> json) =>
+      _$IntentCreationCallbackParamsFromJson(json);
+}