IAP

  Future<void> initPlatformState() async {
    var result = await FlutterInappPurchase.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;

    // refresh items for android
    String msg = await FlutterInappPurchase.consumeAllItems;
    print('consumeAllItems: $msg');
    await _getProduct();
  }

  Future<Null> _getProduct() async {
    List<IAPItem> items = await FlutterInappPurchase.getProducts([Constants.removeAdsProductId]);
    for (var item in items) {
      print('${item.toString()}');
      this._items.add(item);
    }

    setState(() {
      this._items = items;
    });
  }

  List<Widget> _renderButton() {
    List<Widget> widgets = this._items.map((item) =>
      Column(
        children: <Widget>[
          Container(
            height: 250.0,
            width: double.infinity,
            child: Card(
              child: Column(
                children: <Widget>[
                  SizedBox(height: 28.0),
                  Align(
                    alignment: Alignment.center,
                    child: Text(language.removeAdTitle, style: Theme
                      .of(context)
                      .textTheme
                      .display1,),
                  ),
                  SizedBox(height: 24.0),
                  Align(
                    alignment: Alignment.center,
                    child: Text(language.removeAdFirstText, style: TextStyle(fontSize: 16.0, color: Colors.grey[700]),),
                  ),
                  Align(
                    alignment: Alignment.center,
                    child: Text(language.removeAdSecondText, style: TextStyle(fontSize: 16.0, color: Colors.grey[700])),
                  ),
                  SizedBox(height: 24.0),
                  SizedBox(
                    width: 340.0,
                    height: 50.0,
                    child: RaisedButton(
                      onPressed: () => _buyProduct(item),
                      shape: new RoundedRectangleBorder(
                        borderRadius: new BorderRadius.circular(30.0)),
                      child: Text('${language.buy} ${item.price} ${item.currency}', style: Theme.of(context).primaryTextTheme.button,),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      )
    ).toList();
    return widgets;
  }

  @override
  Widget build(BuildContext context) {
    language = AppLocalizations.of(context);

    return Column(
      children: this._renderButton(),
    );
  }