how to get all product from a list of different categories in flutter

i think i understand your problem and i have your problem solution may be this gonna workout in your scenario try to follow these steps:

1. Create a new list to store all products.
2. Iterate through each category and add its products to the new list.
3. Display the merged list of products.

here i am adding my code snippet which may help you out in your query

import 'package:flutter/material.dart';

class Product {
  final String id;
  final String name;
  final double price;

  Product({required this.id, required this.name, required this.price});
}

class CategoryModel {
  final String id;
  final String title;
  final List<Product> products;

  CategoryModel({required this.id, required this.title, required this.products});
}

void main() {
  runApp(MyApp());
}

class Groccerapp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    List<CategoryModel> categories = [
      CategoryModel(id: '1', title: 'Shoes', products: [
        Product(id: '1', name: 'Puma', price: 2304.0),
      ]),
      CategoryModel(id: '2', title: 'Shirts', products: [
        Product(id: '1', name: 'Spykar', price: 2344.0),
      ]),
      CategoryModel(id: '3', title: 'Jeans', products: [
        Product(id: '1', name: 'Killer', price: 7838.0),
        Product(id: '2', name: 'Wrangler', price: 12000.0),
      ]),
    ];

    List<Product> allProducts = [];

    // Merge products from all categories into a single list
    for (var category in categories) {
      allProducts.addAll(category.products);
    }

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Merged Products'),
        ),
        body: ListView.builder(
          itemCount: allProducts.length,
          itemBuilder: (context, index) {
            final product = allProducts[index];
            return ListTile(
              title: Text(product.name),
              subtitle: Text('Price: ${product.price.toStringAsFixed(2)}'),
            );
          },
        ),
      ),
    );
  }
}

i modified it according to your list