Flutter flutter_in_app_purchases subscription FlutterInAppPurchses.instance.getSubscriptions() is not retrieving any items for IAPItem

Question

I'm trying to implement a renewable subscription in flutter using the flutter_in_app_purchases plugin. When I click on the screen that this is declared in, it goes through the initState() function and then gets to the initPlatformState() and goes through that successfully, but when it gets to the getProducts() function, it's returning an empty item list for the List items = FlutterInappPurchase.instance.getSubscriptions([productID]); call. I've added the monthly subscription in both the App Store Connect and Google Play Store and completed the tax forms. Any help would be appreciated.

List<IAPItem> _items = [];
  static const String productID = 'monthly_subscription';

  @override
  void initState() {
    super.initState();
    print("IN INIT STATE");
    initPlatformState();
  }

  Future<void> initPlatformState() async {
    print("In init platform state");
    // prepare
    final bool available = await InAppPurchaseConnection.instance.isAvailable();
    print(available);
    var close = await FlutterInappPurchase.instance.endConnection;
    var result = await FlutterInappPurchase.instance.initConnection;
    print('result: $result');

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) {
      print('In not mounded');
      return;
    }

    // refresh items for android
    /*try {
      String msg = await FlutterInappPurchase.instance.consumeAllItems;
      print('consumeAllItems: $msg');
    } catch(e){
      print(e.toString());
    }*/

    await _getProduct();
  }

  Future<Null> _getProduct() async {
    print("In get products");
    try {
      List<IAPItem> items = await FlutterInappPurchase.instance.getSubscriptions([productID]);
      print("Items is: $items");
      for (var item in items) {
        print('${item.toString()}');
        this._items.add(item);
      }

      setState(() {
        this._items = items;
      });
    } catch(e) {
      print(e.toString());
    }
  }

Answer 1

Here you have a working example from app in production. Disclaimer: I'm not using it anymore but the last time I did it worked fine:

class _InAppState extends State<InApp> {
  StreamSubscription _purchaseUpdatedSubscription;
  StreamSubscription _purchaseErrorSubscription;
  StreamSubscription _conectionSubscription;
  final List<String> _productLists = Platform.isAndroid
      ? [
    'subs_premium', 'subs_user'
  ]
      : ['subs_premium', 'subs_boss', 'subscripcion_user'];


  String _platformVersion = 'Unknown';
  List<IAPItem> _items = [];
  List<IAPItem> _subscripions = [];
  List<PurchasedItem> _purchases = [];

  @override
  void initState() {
    super.initState();
    initPlatformState();
  }

  @override
  void dispose() {
    super.dispose();
    if (_conectionSubscription != null) {
      _conectionSubscription.cancel();
      _conectionSubscription = null;
    }
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> initPlatformState() async {
    String platformVersion;
    // Platform messages may fail, so we use a try/catch PlatformException.
    try {
      platformVersion = await FlutterInappPurchase.instance.platformVersion;
    } on PlatformException {
      platformVersion = 'Failed to get platform version.';
    }

    // prepare
    var result = await FlutterInappPurchase.instance.initConnection;
    print('result: $result');

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      _platformVersion = platformVersion;
    });

    // refresh items for android
    try {
      String msg = await FlutterInappPurchase.instance.consumeAllItems;
      print('consumeAllItems: $msg');
    } catch (err) {
      print('consumeAllItems error: $err');
    }

    _conectionSubscription = FlutterInappPurchase.connectionUpdated.listen((connected) {
      print('connected: $connected');
    });

    _purchaseUpdatedSubscription = FlutterInappPurchase.purchaseUpdated.listen((productItem) {
      print('purchase-updated: $productItem');
    });

    _purchaseErrorSubscription = FlutterInappPurchase.purchaseError.listen((purchaseError) {
      print('purchase-error: $purchaseError');
    });
    final List<String> _SKUS = widget.premium ? ['subs_boss']
        : ['subs_user'] ;
    _getSubscriptions(_SKUS);
  }

  void _requestPurchase(IAPItem item) {
    FlutterInappPurchase.instance.requestPurchase(item.productId);
  }

  Future _getProduct() async {
    print('TEST 1 HERE ${_productLists.length}, ${_productLists.first.toString()}');
    List<IAPItem> items = await FlutterInappPurchase.instance.getProducts(_productLists);
    print('TEST 2 HERE ${items.length}');
    for (var item in items) {
      print('${item.toString()}');
      this._items.add(item);
    }

    setState(() {
      this._items = items;
      this._purchases = [];
    });
  }

  Future _getPurchases() async {
    List<PurchasedItem> items =
    await FlutterInappPurchase.instance.getAvailablePurchases();
    for (var item in items) {
      print('${item.toString()}');
      this._purchases.add(item);
    }

    setState(() {
      this._items = [];
      this._purchases = items;
    });
  }

  Future _getSubscriptions(_SKUS) async {
    List<IAPItem> items =
    await FlutterInappPurchase.instance.getSubscriptions(_SKUS);
    for (var item in items) {
      print('${item.toString()}');
      this._subscripions.add(item);
    }

    setState(() {
      this._items = [];
      this._subscripions = items;
    });
  }

  Future _getPurchaseHistory() async {
    List<PurchasedItem> items = await FlutterInappPurchase.instance.getPurchaseHistory();
    for (var item in items) {
      print('${item.toString()}');
      this._purchases.add(item);
    }

    setState(() {
      this._items = [];
      this._purchases = items;
    });
  }