main.dart

class PaymentScreen extends StatefulWidget {
  const PaymentScreen({Key? key}) : super(key: key);

  @override
  State<StatefulWidget> createState() {
    return _PaymentScreenState();
  }
}

class _PaymentScreenState extends State<PaymentScreen> {
  var price = "\$0.05";

  List<String> productIds = [Platform.isAndroid ? 'android.test.purchased' : 'weekly'];
  FlutterBillingPlugin? billingHelper;

  @override
  void initState() {
    super.initState();
    initBilling();
    initListeners();
    initPrice();
  }

  Future<void> initBilling() async {
    billingHelper = FlutterBillingPlugin();
    //pass secret key for iOS development auto renewal
    await billingHelper?.init(productIds, "a59d0387edeb46e594fc00be5463ab7f", false);
  }

  Future<void> initPrice() async {
    await billingHelper?.getPrice(Platform.isAndroid ? 'android.test.purchased' : 'weekly');
  }

  void initListeners() {
    billingHelper?.setPurchaseUpdateHandler((status, value) async {
      switch (status) {
        case 'isProductPurchased':
          if (kDebugMode) {
            print('$status : $value');
            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                duration: const Duration(seconds: 1),
                backgroundColor: Utils.getPrimaryColor(),
                content: Text(
                  'isProductPurchased: $value',
                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteColor()),
                )));
          }
          break;
        case 'success':
          if (kDebugMode) {
            print('$status : $value');
            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                duration: const Duration(seconds: 1),
                backgroundColor: Utils.getPrimaryColor(),
                content: Text(
                  'Purchase Sucessfully',
                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteColor()),
                )));
          }
          break;
        case 'cancelled':
          if (kDebugMode) {
            print('$status : $value');
            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                duration: const Duration(seconds: 1),
                backgroundColor: Utils.getPrimaryColor(),
                content: Text(
                  'Purchase cancelled by you',
                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteColor()),
                )));
          }
          break;
        case 'error':
          if (kDebugMode) {
            print('$status : $value');
            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                duration: const Duration(seconds: 1),
                backgroundColor: Utils.getPrimaryColor(),
                content: Text(
                  'Something went wrong, Please try again after sometime',
                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteColor()),
                )));
          }
          break;
        case 'restore':
          if (kDebugMode) {
            print('$status : $value');
            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                duration: const Duration(seconds: 1),
                backgroundColor: Utils.getPrimaryColor(),
                content: Text(
                  value ? 'Restore Successfully' : 'You don\'t have purchase to restore',
                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteColor()),
                )));
          }
          break;
        default:
          if (kDebugMode) {
            print('$status : $value');
          }
      }
    });

    billingHelper!.setPriceUpdateHandler((price) {
      if (kDebugMode) {
        print("Price: $price");
        setState(() {
          this.price = price;
        });
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return AnnotatedRegion<SystemUiOverlayStyle>(
      value: const SystemUiOverlayStyle(
        statusBarColor: Colors.transparent,
        statusBarIconBrightness: Brightness.light,
        systemNavigationBarIconBrightness: Brightness.light,
      ),
      child: Scaffold(
        backgroundColor: Utils.getAccentColor(),
        body: Container(
          decoration: const BoxDecoration(
            image: DecorationImage(image: AssetImage('assets/ic_subscription_screen_bg.png'), fit: BoxFit.fill),
          ),
          child: SafeArea(
            child: Stack(children: [
              Align(
                alignment: Alignment.topCenter,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.start,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 12.0),
                      child: Row(
                        mainAxisSize: MainAxisSize.max,
                        children: [
                          IconButton(
                            icon: Image.asset(
                              'assets/ic_subscription_screen_close.png',
                              height: 22.0,
                              width: 22.0,
                              color: Utils.getWhiteTextColor().withOpacity(0.8),
                            ),
                            onPressed: () {},
                          ),
                          const Spacer(),
                          InkWell(
                            borderRadius: const BorderRadius.all(Radius.circular(2.0)),
                            onTap: () {
                              billingHelper!.checkRestore();
                            },
                            child: Row(
                              mainAxisSize: MainAxisSize.min,
                              crossAxisAlignment: CrossAxisAlignment.center,
                              mainAxisAlignment: MainAxisAlignment.center,
                              children: [
                                Text(
                                  "RESTORE",
                                  style: TextStyle(fontSize: 16.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteTextColor().withOpacity(0.9)),
                                ),
                                const SizedBox(
                                  width: 4.0,
                                ),
                                Image.asset(
                                  'assets/ic_subscription_screen_restore.png',
                                  height: 16.0,
                                  width: 16.0,
                                  color: Utils.getWhiteTextColor().withOpacity(0.9),
                                ),
                              ],
                            ),
                          )
                        ],
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 36.0),
                      child: Text(
                        "Become\nPro User",
                        style: TextStyle(fontSize: 43.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, color: Utils.getWhiteTextColor()),
                      ),
                    ),
                    const SizedBox(
                      height: 12.0,
                    ),
                    Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 36.0),
                      child: Text(
                        "Unlock all functions".toUpperCase(),
                        style: TextStyle(fontSize: 16.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, letterSpacing: 4, color: Utils.getWhiteTextColor()),
                      ),
                    ),
                  ],
                ),
              ),
              Align(
                alignment: Alignment.bottomCenter,
                child: Wrap(
                  children: [
                    Column(children: [
                      Center(
                        child: Column(
                          mainAxisSize: MainAxisSize.min,
                          mainAxisAlignment: MainAxisAlignment.start,
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: <Widget>[
                            Row(
                              mainAxisSize: MainAxisSize.min,
                              mainAxisAlignment: MainAxisAlignment.center,
                              children: [
                                Text(
                                  '\u2022',
                                  style: TextStyle(fontSize: 36, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, color: Utils.getYellowColor()),
                                ),
                                const SizedBox(width: 12),
                                Text(
                                  "+200 Questions",
                                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteTextColor()),
                                ),
                              ],
                            ),
                            Row(
                              mainAxisSize: MainAxisSize.min,
                              mainAxisAlignment: MainAxisAlignment.start,
                              children: [
                                Text(
                                  '\u2022',
                                  style: TextStyle(fontSize: 36, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, color: Utils.getYellowColor()),
                                ),
                                const SizedBox(width: 12),
                                Text(
                                  "All Mock Tests",
                                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteTextColor()),
                                ),
                              ],
                            ),
                            Row(
                              mainAxisSize: MainAxisSize.min,
                              mainAxisAlignment: MainAxisAlignment.start,
                              children: [
                                Text(
                                  '\u2022',
                                  style: TextStyle(fontSize: 36, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, color: Utils.getYellowColor()),
                                ),
                                const SizedBox(width: 12),
                                Text(
                                  "All Statistics",
                                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteTextColor()),
                                ),
                              ],
                            ),
                            Row(
                              mainAxisSize: MainAxisSize.min,
                              mainAxisAlignment: MainAxisAlignment.start,
                              children: [
                                Text(
                                  '\u2022',
                                  style: TextStyle(fontSize: 36, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, color: Utils.getYellowColor()),
                                ),
                                const SizedBox(width: 12),
                                Text(
                                  "Check progress",
                                  style: TextStyle(fontSize: 18.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w500, color: Utils.getWhiteTextColor()),
                                ),
                              ],
                            ),
                          ],
                        ),
                      ),
                      const SizedBox(
                        height: 12.0,
                      ),
                      Text(
                        "3 days free trial, then $price/week.\ncancel at any time",
                        textAlign: TextAlign.center,
                        style: TextStyle(fontSize: 14.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w300, color: Utils.getWhiteTextColor().withOpacity(.5)),
                      ),
                      const SizedBox(
                        height: 12.0,
                      ),
                      Padding(
                        padding: const EdgeInsets.symmetric(horizontal: 36.0),
                        child: MaterialButton(
                          elevation: 0.0,
                          minWidth: double.infinity,
                          color: Utils.getYellowColor(),
                          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12.0)),
                          padding: const EdgeInsets.symmetric(horizontal: 12.0, vertical: 16.0),
                          onPressed: () {
                            billingHelper!.buyProduct(Platform.isAndroid ? 'android.test.purchased' : 'weekly');
                          },
                          child: Text(
                            "Unlock now".toUpperCase(),
                            style: TextStyle(fontSize: 16.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w700, color: Utils.getButtonTextColor()),
                          ),
                        ),
                      ),
                      const SizedBox(
                        height: 8.0,
                      ),
                      SizedBox(
                        height: 44.0,
                        child: Padding(
                          padding: const EdgeInsets.symmetric(horizontal: 36.0),
                          child: SingleChildScrollView(
                            physics: const AlwaysScrollableScrollPhysics(),
                            scrollDirection: Axis.vertical,
                            child: Text(
                              "After you start the subscription, you will be able to use all the advanced features. Premium subscriptions are charged weekly/monthly/yearly at the rate corresponding to the selected plan. When confirming the purchase, the fee will be charged through the payment method you selected. The account will be charged for renewal within 24 hours before the end of the current period. You can cancel your subscription within 24 hours before the end of the current period, otherwise the subscription will automatically renew.",
                              textAlign: TextAlign.center,
                              // maxLines: 3,
                              style: TextStyle(fontSize: 12.0, fontFamily: 'Sans', fontStyle: FontStyle.normal, fontWeight: FontWeight.w300, color: Utils.getWhiteTextColor().withOpacity(.5)),
                            ),
                          ),
                        ),
                      ),
                      const SizedBox(height: 12.0),
                    ])
                  ],
                ),
              )
            ]),
          ),
        ),
      ),
    );
  }
}