Flutter 内购初始化问题

Question

你好，我在官方 flutter 插件 in_app_purchase: ^3.0.7 的帮助下，在我的应用程序中使用 in purchase 购买非消耗品。但问题是，当我第一次在用户购买时启动我的应用内购买屏幕。它不会第一次初始化 google play 对话以进行付款，但如果用户返回 sacreen 然后来到这个 sacreen 它会正常工作。谁能告诉我为什么它不能在第一次初始化时工作。下面是我的代码。

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:in_app_purchase/in_app_purchase.dart';
import 'package:shared_preferences/shared_preferences.dart';


class Purchasenow extends StatefulWidget {


  @override
  State<Purchasenow> createState() => _PurchasenowState();
}

class _PurchasenowState extends State<Purchasenow> {
  final Set<String> _productIds = {'urdubible'};
  late List<ProductDetails> _products;



  @override
  void initState() {
    super.initState();
    _loadProducts();
    _checkPurchaseStatus();
    // initialize the in-app purchase plugin
    InAppPurchase .instance.purchaseStream
        .listen((List<PurchaseDetails> purchases) {
      // handle any purchase updates
      _handlePurchaseUpdates(purchases);
    });

    // load the available products

  }

  Future<void> _loadProducts() async {
    // get the product details from the store
    ProductDetailsResponse response =
    await InAppPurchase.instance.queryProductDetails(_productIds);
    // save the product details to state
    setState(() {
      _products = response.productDetails;
    });
  }

  void _handlePurchaseUpdates(List<PurchaseDetails> purchases) {
    for (PurchaseDetails purchase in purchases) {
      switch (purchase.status) {
        case PurchaseStatus.purchased:
          _savePurchaseStatus(true);

          // handle the purchase, e.g. update UI, save the purchase to database, etc.
          setState(() {


          });
          break;
        case PurchaseStatus.error:
        // handle any purchase errors
          break;
        case PurchaseStatus.canceled:
        // handle cancelled purchases
          break;
      }
    }
  }


  Future<void> _purchaseProduct() async {
    if (_products.isNotEmpty) {
      // initiate the purchase flow
      final PurchaseParam purchaseParam = PurchaseParam(productDetails: _products.first);
      InAppPurchase.instance.buyNonConsumable(purchaseParam: purchaseParam);
    }
  }


  Future<void> _savePurchaseStatus(bool isPurchased) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    prefs.setBool('isPurchased', isPurchased);
  }

  Future<void> _checkPurchaseStatus() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    bool? isPurchased = prefs.getBool('isPurchased');

    if (isPurchased != null && isPurchased) {
      setState(() {

      });
    }
  }



  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        elevation: 0.0,
        title: Text('ADS FREE'),
      ),
      body: Padding(
        padding: EdgeInsets.all(10),
        child: Column(

          children: [
            Text(

              "بٹن پر کلک کریں اور اس ایپ کے تاحیات استعمال کے لیے ادائیگی کریں.۔",style: GoogleFonts.notoNastaliqUrdu(
                fontSize: 18
            ),
              textDirection: TextDirection.rtl,


            ),
            SizedBox(height: 10,),
            Text(

              "Click on button and make the payment for  life time usage of this app.",style: TextStyle(
                fontSize: 22
            ),




            ),
            SizedBox(height: 45,),
            Center(
              child: Center(child: SizedBox(
                width: 200.0,
                height: 40,
                child:ElevatedButton(
                    style: ElevatedButton.styleFrom(),
                    onPressed: _purchaseProduct,
                    child: const Text('Purchase Now!')
                ),
              )),
            ),
          ],

        ),
      ),
    );
  }
}