Flutter In-App Purchase Helper #

A thin, tested wrapper around in_app_purchase that handles the bookkeeping most integrations get wrong: completing transactions, telling pending and canceled purchases apart from real failures, and surfacing store misconfiguration instead of silently returning an empty product list.

Install #

dependencies:
  flutter_in_app_purchase_helper: ^0.1.0

You still need to configure your products in Play Console and App Store Connect, and follow the platform setup in the in_app_purchase README.

Usage #

Initialize #

Create the helper, then initialize it with your product IDs and the callbacks you care about. Only the first four are required.

import 'package:flutter_in_app_purchase_helper/flutter_in_app_purchase_helper.dart';

final FlutterInAppPurchaseHelper _helper = FlutterInAppPurchaseHelper();

@override
void initState() {
  super.initState();
  _helper.initialize(
    productIds: {'monthly_plan', 'yearly_plan'},
    onProductsFetched: (products) {
      setState(() => _products = products);
    },
    onPurchaseSuccess: (purchase) {
      // Fires for both new purchases and restores.
      _unlockContent(purchase);
    },
    onPurchaseError: (error) {
      _showSnackBar(error);
    },
    // Optional:
    onPurchasePending: (purchase) => _showSpinner(),
    onPurchaseCanceled: (purchase) => _hideSpinner(),
  );
}

Calling initialize more than once is a no-op until you dispose, so a rebuild cannot register duplicate listeners.

Show the products #

onProductsFetched gives you ProductDetails straight from the store, so prices and currencies are already localized. Use product.price rather than formatting rawPrice yourself.

ListView.builder(
  itemCount: _products.length,
  itemBuilder: (context, index) {
    final product = _products[index];
    return ListTile(
      title: Text(product.title),
      subtitle: Text(product.description),
      trailing: Text(product.price),
      onTap: () => setState(() => _selected = product),
    );
  },
)

Buy #

final sent = await _helper.buyProduct(product, (error) => _showSnackBar(error));

if (!sent) {
  // The request never reached the store; stop any spinner you started.
}

buyProduct returns whether the request was sent. The outcome arrives on the callbacks you gave to initialize.

For consumables, pass consumable: true:

await _helper.buyProduct(coinPack, _showSnackBar, consumable: true);

Restore #

The App Store requires a restore entry point for any app selling non-consumables or subscriptions. Restored purchases arrive on onPurchaseSuccess.

TextButton(
  onPressed: () => _helper.restorePurchases(onError: _showSnackBar),
  child: const Text('Restore purchases'),
)

Dispose #

@override
void dispose() {
  _helper.dispose();
  super.dispose();
}

Verifying purchases #

onPurchaseSuccess fires on the client's word alone. For anything revenue-bearing, send purchase.verificationData.serverVerificationData to your backend and validate it with Apple or Google before unlocking content.

What the helper handles for you #

API #

Example #

A complete plan-picker screen lives in example/lib/main.dart.

License #

MIT — see LICENSE.