Flutter 如何将应用内购买功能添加到我的Flitter应用程序？

我将向我的Flitter应用程序添加应用程序内购买功能，但找不到任何有关应用程序内购买的相关信息或示例应用程序，是否有人可以共享包含应用程序内购买功能的任何链接或示例应用程序？

---

谢谢

看看这个包裹

示例代码：

import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:in_app_purchase/in_app_purchase.dart';
import 'consumable_store.dart';

void main() {
  // For play billing library 2.0 on Android, it is mandatory to call
  // [enablePendingPurchases](https://developer.android.com/reference/com/android/billingclient/api/BillingClient.Builder.html#enablependingpurchases)
  // as part of initializing the app.
  InAppPurchaseConnection.enablePendingPurchases();
  runApp(MyApp());
}

const bool kAutoConsume = true;

const String _kConsumableId = 'consumable';
const List<String> _kProductIds = <String>[
  _kConsumableId,
  'upgrade',
  'subscription'
];

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final InAppPurchaseConnection _connection = InAppPurchaseConnection.instance;
  StreamSubscription<List<PurchaseDetails>> _subscription;
  List<String> _notFoundIds = [];
  List<ProductDetails> _products = [];
  List<PurchaseDetails> _purchases = [];
  List<String> _consumables = [];
  bool _isAvailable = false;
  bool _purchasePending = false;
  bool _loading = true;
  String _queryProductError;

  @override
  void initState() {
    Stream purchaseUpdated =
        InAppPurchaseConnection.instance.purchaseUpdatedStream;
    _subscription = purchaseUpdated.listen((purchaseDetailsList) {
      _listenToPurchaseUpdated(purchaseDetailsList);
    }, onDone: () {
      _subscription.cancel();
    }, onError: (error) {
      // handle error here.
    });
    initStoreInfo();
    super.initState();
  }

  Future<void> initStoreInfo() async {
    final bool isAvailable = await _connection.isAvailable();
    if (!isAvailable) {
      setState(() {
        _isAvailable = isAvailable;
        _products = [];
        _purchases = [];
        _notFoundIds = [];
        _consumables = [];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    ProductDetailsResponse productDetailResponse =
        await _connection.queryProductDetails(_kProductIds.toSet());
    if (productDetailResponse.error != null) {
      setState(() {
        _queryProductError = productDetailResponse.error.message;
        _isAvailable = isAvailable;
        _products = productDetailResponse.productDetails;
        _purchases = [];
        _notFoundIds = productDetailResponse.notFoundIDs;
        _consumables = [];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    if (productDetailResponse.productDetails.isEmpty) {
      setState(() {
        _queryProductError = null;
        _isAvailable = isAvailable;
        _products = productDetailResponse.productDetails;
        _purchases = [];
        _notFoundIds = productDetailResponse.notFoundIDs;
        _consumables = [];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    final QueryPurchaseDetailsResponse purchaseResponse =
        await _connection.queryPastPurchases();
    if (purchaseResponse.error != null) {
      // handle query past purchase error..
    }
    final List<PurchaseDetails> verifiedPurchases = [];
    for (PurchaseDetails purchase in purchaseResponse.pastPurchases) {
      if (await _verifyPurchase(purchase)) {
        verifiedPurchases.add(purchase);
      }
    }
    List<String> consumables = await ConsumableStore.load();
    setState(() {
      _isAvailable = isAvailable;
      _products = productDetailResponse.productDetails;
      _purchases = verifiedPurchases;
      _notFoundIds = productDetailResponse.notFoundIDs;
      _consumables = consumables;
      _purchasePending = false;
      _loading = false;
    });
  }

  @override
  void dispose() {
    _subscription.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    List<Widget> stack = [];
    if (_queryProductError == null) {
      stack.add(
        ListView(
          children: [
            _buildConnectionCheckTile(),
            _buildProductList(),
            _buildConsumableBox(),
          ],
        ),
      );
    } else {
      stack.add(Center(
        child: Text(_queryProductError),
      ));
    }
    if (_purchasePending) {
      stack.add(
        Stack(
          children: [
            Opacity(
              opacity: 0.3,
              child: const ModalBarrier(dismissible: false, color: Colors.grey),
            ),
            Center(
              child: CircularProgressIndicator(),
            ),
          ],
        ),
      );
    }

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('IAP Example'),
        ),
        body: Stack(
          children: stack,
        ),
      ),
    );
  }

  Card _buildConnectionCheckTile() {
    if (_loading) {
      return Card(child: ListTile(title: const Text('Trying to connect...')));
    }
    final Widget storeHeader = ListTile(
      leading: Icon(_isAvailable ? Icons.check : Icons.block,
          color: _isAvailable ? Colors.green : ThemeData.light().errorColor),
      title: Text(
          'The store is ' + (_isAvailable ? 'available' : 'unavailable') + '.'),
    );
    final List<Widget> children = <Widget>[storeHeader];

    if (!_isAvailable) {
      children.addAll([
        Divider(),
        ListTile(
          title: Text('Not connected',
              style: TextStyle(color: ThemeData.light().errorColor)),
          subtitle: const Text(
              'Unable to connect to the payments processor. Has this app been configured correctly? See the example README for instructions.'),
        ),
      ]);
    }
    return Card(child: Column(children: children));
  }

  Card _buildProductList() {
    if (_loading) {
      return Card(
          child: (ListTile(
              leading: CircularProgressIndicator(),
              title: Text('Fetching products...'))));
    }
    if (!_isAvailable) {
      return Card();
    }
    final ListTile productHeader = ListTile(title: Text('Products for Sale'));
    List<ListTile> productList = <ListTile>[];
    if (_notFoundIds.isNotEmpty) {
      productList.add(ListTile(
          title: Text('[${_notFoundIds.join(", ")}] not found',
              style: TextStyle(color: ThemeData.light().errorColor)),
          subtitle: Text(
              'This app needs special configuration to run. Please see example/README.md for instructions.')));
    }

    // This loading previous purchases code is just a demo. Please do not use this as it is.
    // In your app you should always verify the purchase data using the `verificationData` inside the [PurchaseDetails] object before trusting it.
    // We recommend that you use your own server to verity the purchase data.
    Map<String, PurchaseDetails> purchases =
        Map.fromEntries(_purchases.map((PurchaseDetails purchase) {
      if (purchase.pendingCompletePurchase) {
        InAppPurchaseConnection.instance.completePurchase(purchase);
      }
      return MapEntry<String, PurchaseDetails>(purchase.productID, purchase);
    }));
    productList.addAll(_products.map(
      (ProductDetails productDetails) {
        PurchaseDetails previousPurchase = purchases[productDetails.id];
        return ListTile(
            title: Text(
              productDetails.title,
            ),
            subtitle: Text(
              productDetails.description,
            ),
            trailing: previousPurchase != null
                ? Icon(Icons.check)
                : FlatButton(
                    child: Text(productDetails.price),
                    color: Colors.green[800],
                    textColor: Colors.white,
                    onPressed: () {
                      PurchaseParam purchaseParam = PurchaseParam(
                          productDetails: productDetails,
                          applicationUserName: null,
                          sandboxTesting: true);
                      if (productDetails.id == _kConsumableId) {
                        _connection.buyConsumable(
                            purchaseParam: purchaseParam,
                            autoConsume: kAutoConsume || Platform.isIOS);
                      } else {
                        _connection.buyNonConsumable(
                            purchaseParam: purchaseParam);
                      }
                    },
                  ));
      },
    ));

    return Card(
        child:
            Column(children: <Widget>[productHeader, Divider()] + productList));
  }

  Card _buildConsumableBox() {
    if (_loading) {
      return Card(
          child: (ListTile(
              leading: CircularProgressIndicator(),
              title: Text('Fetching consumables...'))));
    }
    if (!_isAvailable || _notFoundIds.contains(_kConsumableId)) {
      return Card();
    }
    final ListTile consumableHeader =
        ListTile(title: Text('Purchased consumables'));
    final List<Widget> tokens = _consumables.map((String id) {
      return GridTile(
        child: IconButton(
          icon: Icon(
            Icons.stars,
            size: 42.0,
            color: Colors.orange,
          ),
          splashColor: Colors.yellowAccent,
          onPressed: () => consume(id),
        ),
      );
    }).toList();
    return Card(
        child: Column(children: <Widget>[
      consumableHeader,
      Divider(),
      GridView.count(
        crossAxisCount: 5,
        children: tokens,
        shrinkWrap: true,
        padding: EdgeInsets.all(16.0),
      )
    ]));
  }

  Future<void> consume(String id) async {
    await ConsumableStore.consume(id);
    final List<String> consumables = await ConsumableStore.load();
    setState(() {
      _consumables = consumables;
    });
  }

  void showPendingUI() {
    setState(() {
      _purchasePending = true;
    });
  }

  void deliverProduct(PurchaseDetails purchaseDetails) async {
    // IMPORTANT!! Always verify a purchase purchase details before delivering the product.
    if (purchaseDetails.productID == _kConsumableId) {
      await ConsumableStore.save(purchaseDetails.purchaseID);
      List<String> consumables = await ConsumableStore.load();
      setState(() {
        _purchasePending = false;
        _consumables = consumables;
      });
    } else {
      setState(() {
        _purchases.add(purchaseDetails);
        _purchasePending = false;
      });
    }
  }

  void handleError(IAPError error) {
    setState(() {
      _purchasePending = false;
    });
  }

  Future<bool> _verifyPurchase(PurchaseDetails purchaseDetails) {
    // IMPORTANT!! Always verify a purchase before delivering the product.
    // For the purpose of an example, we directly return true.
    return Future<bool>.value(true);
  }

  void _handleInvalidPurchase(PurchaseDetails purchaseDetails) {
    // handle invalid purchase here if  _verifyPurchase` failed.
  }

  void _listenToPurchaseUpdated(List<PurchaseDetails> purchaseDetailsList) {
    purchaseDetailsList.forEach((PurchaseDetails purchaseDetails) async {
      if (purchaseDetails.status == PurchaseStatus.pending) {
        showPendingUI();
      } else {
        if (purchaseDetails.status == PurchaseStatus.error) {
          handleError(purchaseDetails.error);
        } else if (purchaseDetails.status == PurchaseStatus.purchased) {
          bool valid = await _verifyPurchase(purchaseDetails);
          if (valid) {
            deliverProduct(purchaseDetails);
          } else {
            _handleInvalidPurchase(purchaseDetails);
            return;
          }
        }
        if (Platform.isAndroid) {
          if (!kAutoConsume && purchaseDetails.productID == _kConsumableId) {
            await InAppPurchaseConnection.instance
                .consumePurchase(purchaseDetails);
          }
        }
        if (purchaseDetails.pendingCompletePurchase) {
          await InAppPurchaseConnection.instance
              .completePurchase(purchaseDetails);
        }
      }
    });
  }
}

导入'dart:async'；
导入“dart:io”；
进口“包装：颤振/材料.省道”；
导入“包：应用程序内购买/应用程序内购买.dart”；
进口“消耗品仓库.dart”；
void main（）{
//对于Android上的play billing library 2.0，必须调用
//[支持暂停购买](https://developer.android.com/reference/com/android/billingclient/api/BillingClient.Builder.html#enablependingpurchases)
//作为初始化应用程序的一部分。
InAppPurchaseConnection.enablePendingPurchases（）；
runApp（MyApp（））；
}
const bool kAutoConsume=true；
常量字符串kConsumableId='consumableid'；
常量列表\u kProductId=[
_kConsumableId，
“升级”，
“订阅”
];
类MyApp扩展了StatefulWidget{
@凌驾
_MyAppState createState（）=>\u MyAppState（）；
}
类MyAppState扩展了状态{
final InAppPurchaseConnection _connection=InAppPurchaseConnection.instance；
流动认购(流动认购);；
列表_notFoundIds=[]；
列表_产品=[]；
清单_采购=[]；
清单_消耗品=[]；
bool_isAvailable=false；
bool_purchasePending=false；
bool_加载=真；
字符串_queryProductError；
@凌驾
void initState（）{
流购买更新=
InAppPurchaseConnection.instance.purchaseUpdatedStream；
_订阅=purchaseUpdated.listen（（purchaseDetailsList）{
_ListentPurchaseUpdated（purchaseDetailsList）；
}，onDone:（）{
_订阅。取消（）；
}，onError:（错误）{
//在这里处理错误。
});
initStoreInfo（）；
super.initState（）；
}
Future initStoreInfo（）异步{
final bool isAvailable=wait_connection.isAvailable（）；
如果（！i可用）{
设置状态（）{
_i可用=i可用；
_产品=[]；
_采购=[]；
_notFoundIds=[]；
_消耗品=[]；
_purchasePending=false；
_加载=假；
});
返回；
}
ProductDetails响应productDetailResponse=
wait_connection.queryProductDetails（_kProductId.toSet（））；
if（productDetailResponse.error！=null）{
设置状态（）{
_queryProductError=productDetailResponse.error.message；
_i可用=i可用；
_products=productDetailResponse.productDetails；
_采购=[]；
_NotFoundId=productDetailResponse.NotFoundId；
_消耗品=[]；
_purchasePending=false；
_加载=假；
});
返回；
}
if（productDetailResponse.productDetails.isEmpty）{
设置状态（）{
_queryProductError=null；
_i可用=i可用；
_products=productDetailResponse.productDetails；
_采购=[]；
_NotFoundId=productDetailResponse.NotFoundId；
_消耗品=[]；
_purchasePending=false；
_加载=假；
});
返回；
}
最终查询PurchaseDetails响应purchaseResponse=
wait_connection.queryPastPurchases（）；
if（purchaseResponse.error！=null）{
//处理查询过去的购买错误。。
}
最终清单验证采购=[]；
for（purchaseResponse.pastPurchases中的PurchaseDetails购买）{
如果（等待_验证采购（采购））{
验证采购。添加（采购）；
}
}
列出耗材=等待ConsumableStore.load（）；
设置状态（）{
_i可用=i可用；
_products=productDetailResponse.productDetails；
_采购=验证采购；
_NotFoundId=productDetailResponse.NotFoundId；
_消耗品=消耗品；
_purchasePending=false；
_加载=假；
});
}
@凌驾
无效处置（）{
_订阅。取消（）；
super.dispose（）；
}
@凌驾
小部件构建（构建上下文）{
列表堆栈=[]；
if（_queryProductError==null）{
stack.add(
列表视图(
儿童：[
_buildConnectionCheckFile（），
_buildProductList（），
_buildConsumableBox（），
],
),
);
}否则{
堆栈。添加（中间）(
子项：文本（_queryProductError），
));
}
如果（_purchasePending）{
stack.add(
堆叠(
儿童：[
不透明(
不透明度：0.3，
孩子：const ModalBarrier（可驳回：假，颜色：颜色。灰色），
),
居中(
子对象：CircularProgressIndicator（），
),
],
),
);
}
返回材料PP(
家：脚手架(
appBar:appBar(
标题：常量文本（“IAP示例”），
),
主体：堆栈(
孩子们：斯塔克，
),
),
);
}
卡_buildConnectionCheckFile（）{
如果（_加载）{
返回卡（子项：ListTile（标题：const Text（'尝试连接…'））；
}
最终小部件storeHeader=ListTile(
前导：图标（_isAvailable？Icons.check:Icons.block，
颜色：_isAvailable？Colors.green:ThemeData.light（）.errorColor），
标题：正文(
'存储区为'+（_isAvailable？'available'：'available'）+'，
);
最终列表子项=[storeHeader]；
如果（！\u可用）{
孩子们([
分隔符（），
列表砖(
标题：文本（'未连接'，
样式：TextStyle（颜色：ThemeData.light（）.errorColor）），
字幕：const Text(
“无法连接到支付处理器。此应用是否已正确配置？有关说明，请参阅示例自述。”），
),
]);
}
返回卡（子项：列（子项：子项））；
}
卡片_buildProductList（）{
import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:in_app_purchase/in_app_purchase.dart';
import 'consumable_store.dart';

void main() {
  // For play billing library 2.0 on Android, it is mandatory to call
  // [enablePendingPurchases](https://developer.android.com/reference/com/android/billingclient/api/BillingClient.Builder.html#enablependingpurchases)
  // as part of initializing the app.
  InAppPurchaseConnection.enablePendingPurchases();
  runApp(MyApp());
}

const bool kAutoConsume = true;

const String _kConsumableId = 'consumable';
const List<String> _kProductIds = <String>[
  _kConsumableId,
  'upgrade',
  'subscription'
];

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final InAppPurchaseConnection _connection = InAppPurchaseConnection.instance;
  StreamSubscription<List<PurchaseDetails>> _subscription;
  List<String> _notFoundIds = [];
  List<ProductDetails> _products = [];
  List<PurchaseDetails> _purchases = [];
  List<String> _consumables = [];
  bool _isAvailable = false;
  bool _purchasePending = false;
  bool _loading = true;
  String _queryProductError;

  @override
  void initState() {
    Stream purchaseUpdated =
        InAppPurchaseConnection.instance.purchaseUpdatedStream;
    _subscription = purchaseUpdated.listen((purchaseDetailsList) {
      _listenToPurchaseUpdated(purchaseDetailsList);
    }, onDone: () {
      _subscription.cancel();
    }, onError: (error) {
      // handle error here.
    });
    initStoreInfo();
    super.initState();
  }

  Future<void> initStoreInfo() async {
    final bool isAvailable = await _connection.isAvailable();
    if (!isAvailable) {
      setState(() {
        _isAvailable = isAvailable;
        _products = [];
        _purchases = [];
        _notFoundIds = [];
        _consumables = [];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    ProductDetailsResponse productDetailResponse =
        await _connection.queryProductDetails(_kProductIds.toSet());
    if (productDetailResponse.error != null) {
      setState(() {
        _queryProductError = productDetailResponse.error.message;
        _isAvailable = isAvailable;
        _products = productDetailResponse.productDetails;
        _purchases = [];
        _notFoundIds = productDetailResponse.notFoundIDs;
        _consumables = [];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    if (productDetailResponse.productDetails.isEmpty) {
      setState(() {
        _queryProductError = null;
        _isAvailable = isAvailable;
        _products = productDetailResponse.productDetails;
        _purchases = [];
        _notFoundIds = productDetailResponse.notFoundIDs;
        _consumables = [];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    final QueryPurchaseDetailsResponse purchaseResponse =
        await _connection.queryPastPurchases();
    if (purchaseResponse.error != null) {
      // handle query past purchase error..
    }
    final List<PurchaseDetails> verifiedPurchases = [];
    for (PurchaseDetails purchase in purchaseResponse.pastPurchases) {
      if (await _verifyPurchase(purchase)) {
        verifiedPurchases.add(purchase);
      }
    }
    List<String> consumables = await ConsumableStore.load();
    setState(() {
      _isAvailable = isAvailable;
      _products = productDetailResponse.productDetails;
      _purchases = verifiedPurchases;
      _notFoundIds = productDetailResponse.notFoundIDs;
      _consumables = consumables;
      _purchasePending = false;
      _loading = false;
    });
  }

  @override
  void dispose() {
    _subscription.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    List<Widget> stack = [];
    if (_queryProductError == null) {
      stack.add(
        ListView(
          children: [
            _buildConnectionCheckTile(),
            _buildProductList(),
            _buildConsumableBox(),
          ],
        ),
      );
    } else {
      stack.add(Center(
        child: Text(_queryProductError),
      ));
    }
    if (_purchasePending) {
      stack.add(
        Stack(
          children: [
            Opacity(
              opacity: 0.3,
              child: const ModalBarrier(dismissible: false, color: Colors.grey),
            ),
            Center(
              child: CircularProgressIndicator(),
            ),
          ],
        ),
      );
    }

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('IAP Example'),
        ),
        body: Stack(
          children: stack,
        ),
      ),
    );
  }

  Card _buildConnectionCheckTile() {
    if (_loading) {
      return Card(child: ListTile(title: const Text('Trying to connect...')));
    }
    final Widget storeHeader = ListTile(
      leading: Icon(_isAvailable ? Icons.check : Icons.block,
          color: _isAvailable ? Colors.green : ThemeData.light().errorColor),
      title: Text(
          'The store is ' + (_isAvailable ? 'available' : 'unavailable') + '.'),
    );
    final List<Widget> children = <Widget>[storeHeader];

    if (!_isAvailable) {
      children.addAll([
        Divider(),
        ListTile(
          title: Text('Not connected',
              style: TextStyle(color: ThemeData.light().errorColor)),
          subtitle: const Text(
              'Unable to connect to the payments processor. Has this app been configured correctly? See the example README for instructions.'),
        ),
      ]);
    }
    return Card(child: Column(children: children));
  }

  Card _buildProductList() {
    if (_loading) {
      return Card(
          child: (ListTile(
              leading: CircularProgressIndicator(),
              title: Text('Fetching products...'))));
    }
    if (!_isAvailable) {
      return Card();
    }
    final ListTile productHeader = ListTile(title: Text('Products for Sale'));
    List<ListTile> productList = <ListTile>[];
    if (_notFoundIds.isNotEmpty) {
      productList.add(ListTile(
          title: Text('[${_notFoundIds.join(", ")}] not found',
              style: TextStyle(color: ThemeData.light().errorColor)),
          subtitle: Text(
              'This app needs special configuration to run. Please see example/README.md for instructions.')));
    }

    // This loading previous purchases code is just a demo. Please do not use this as it is.
    // In your app you should always verify the purchase data using the `verificationData` inside the [PurchaseDetails] object before trusting it.
    // We recommend that you use your own server to verity the purchase data.
    Map<String, PurchaseDetails> purchases =
        Map.fromEntries(_purchases.map((PurchaseDetails purchase) {
      if (purchase.pendingCompletePurchase) {
        InAppPurchaseConnection.instance.completePurchase(purchase);
      }
      return MapEntry<String, PurchaseDetails>(purchase.productID, purchase);
    }));
    productList.addAll(_products.map(
      (ProductDetails productDetails) {
        PurchaseDetails previousPurchase = purchases[productDetails.id];
        return ListTile(
            title: Text(
              productDetails.title,
            ),
            subtitle: Text(
              productDetails.description,
            ),
            trailing: previousPurchase != null
                ? Icon(Icons.check)
                : FlatButton(
                    child: Text(productDetails.price),
                    color: Colors.green[800],
                    textColor: Colors.white,
                    onPressed: () {
                      PurchaseParam purchaseParam = PurchaseParam(
                          productDetails: productDetails,
                          applicationUserName: null,
                          sandboxTesting: true);
                      if (productDetails.id == _kConsumableId) {
                        _connection.buyConsumable(
                            purchaseParam: purchaseParam,
                            autoConsume: kAutoConsume || Platform.isIOS);
                      } else {
                        _connection.buyNonConsumable(
                            purchaseParam: purchaseParam);
                      }
                    },
                  ));
      },
    ));

    return Card(
        child:
            Column(children: <Widget>[productHeader, Divider()] + productList));
  }

  Card _buildConsumableBox() {
    if (_loading) {
      return Card(
          child: (ListTile(
              leading: CircularProgressIndicator(),
              title: Text('Fetching consumables...'))));
    }
    if (!_isAvailable || _notFoundIds.contains(_kConsumableId)) {
      return Card();
    }
    final ListTile consumableHeader =
        ListTile(title: Text('Purchased consumables'));
    final List<Widget> tokens = _consumables.map((String id) {
      return GridTile(
        child: IconButton(
          icon: Icon(
            Icons.stars,
            size: 42.0,
            color: Colors.orange,
          ),
          splashColor: Colors.yellowAccent,
          onPressed: () => consume(id),
        ),
      );
    }).toList();
    return Card(
        child: Column(children: <Widget>[
      consumableHeader,
      Divider(),
      GridView.count(
        crossAxisCount: 5,
        children: tokens,
        shrinkWrap: true,
        padding: EdgeInsets.all(16.0),
      )
    ]));
  }

  Future<void> consume(String id) async {
    await ConsumableStore.consume(id);
    final List<String> consumables = await ConsumableStore.load();
    setState(() {
      _consumables = consumables;
    });
  }

  void showPendingUI() {
    setState(() {
      _purchasePending = true;
    });
  }

  void deliverProduct(PurchaseDetails purchaseDetails) async {
    // IMPORTANT!! Always verify a purchase purchase details before delivering the product.
    if (purchaseDetails.productID == _kConsumableId) {
      await ConsumableStore.save(purchaseDetails.purchaseID);
      List<String> consumables = await ConsumableStore.load();
      setState(() {
        _purchasePending = false;
        _consumables = consumables;
      });
    } else {
      setState(() {
        _purchases.add(purchaseDetails);
        _purchasePending = false;
      });
    }
  }

  void handleError(IAPError error) {
    setState(() {
      _purchasePending = false;
    });
  }

  Future<bool> _verifyPurchase(PurchaseDetails purchaseDetails) {
    // IMPORTANT!! Always verify a purchase before delivering the product.
    // For the purpose of an example, we directly return true.
    return Future<bool>.value(true);
  }

  void _handleInvalidPurchase(PurchaseDetails purchaseDetails) {
    // handle invalid purchase here if  _verifyPurchase` failed.
  }

  void _listenToPurchaseUpdated(List<PurchaseDetails> purchaseDetailsList) {
    purchaseDetailsList.forEach((PurchaseDetails purchaseDetails) async {
      if (purchaseDetails.status == PurchaseStatus.pending) {
        showPendingUI();
      } else {
        if (purchaseDetails.status == PurchaseStatus.error) {
          handleError(purchaseDetails.error);
        } else if (purchaseDetails.status == PurchaseStatus.purchased) {
          bool valid = await _verifyPurchase(purchaseDetails);
          if (valid) {
            deliverProduct(purchaseDetails);
          } else {
            _handleInvalidPurchase(purchaseDetails);
            return;
          }
        }
        if (Platform.isAndroid) {
          if (!kAutoConsume && purchaseDetails.productID == _kConsumableId) {
            await InAppPurchaseConnection.instance
                .consumePurchase(purchaseDetails);
          }
        }
        if (purchaseDetails.pendingCompletePurchase) {
          await InAppPurchaseConnection.instance
              .completePurchase(purchaseDetails);
        }
      }
    });
  }
}