main.dart

             import 'package:flutter/material.dart';
import 'package:b/filter_screen.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(

      home: FilterScreen(),
      debugShowCheckedModeBanner: false,
    );
  }
}

services.dart

import 'dart:convert';

import 'package:b/model.dart';
import 'package:http/http.dart' as http;

class ApiServices {
  Future<FilterModel?> myFilterList() async {
    Uri url = Uri.parse("https://dummyjson.com/products");
    var response = await http.get(url);
    try {
      if (response.statusCode == 200) {
        return FilterModel.fromJson(jsonDecode(response.body));
      } else {
        return null;
      }
    } catch (e) {
      print(e);
    }
    return null;
  }
}
// the error message shown due to the rating value,
// in some product  rating value in the form of double in some product it's value is iintn  form.

model.dart

class FilterModel {
  List<Products>? products;
  num? total;
  num? skip;
  num? limit;

  FilterModel({this.products, this.total, this.skip, this.limit});

  FilterModel.fromJson(Map<String, dynamic> json) {
    if (json['products'] != null) {
      products = <Products>[];
      json['products'].forEach((v) {
        products!.add(Products.fromJson(v));
      });
    }
    total = json['total'];
    skip = json['skip'];
    limit = json['limit'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = Map<String, dynamic>();
    if (products != null) {
      data['products'] = products!.map((v) => v.toJson()).toList();
    }
    data['total'] = total;
    data['skip'] = skip;
    data['limit'] = limit;
    return data;
  }
}

class Products {
  num? id;
  String? title;
  String? description;
  num? price;
  num? discountPercentage;
  dynamic rating;
  num? stock;
  String? brand;
  String? category;
  String? thumbnail;
  List<String>? images;

  Products(
      {this.id,
        this.title,
        this.description,
        this.price,
        this.discountPercentage,
        this.rating,
        this.stock,
        this.brand,
        this.category,
        this.thumbnail,
        this.images});

  Products.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    title = json['title'];
    description = json['description'];
    price = json['price'];
    discountPercentage = json['discountPercentage'];
    rating = json['rating'];
    stock = json['stock'];
    brand = json['brand'];
    category = json['category'];
    thumbnail = json['thumbnail'];
    images = json['images'].cast<String>();
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = Map<String, dynamic>();
    data['id'] = id;
    data['title'] = title;
    data['description'] = description;
    data['price'] = price;
    data['discountPercentage'] = discountPercentage;
    data['rating'] = rating;
    data['stock'] = stock;
    data['brand'] = brand;
    data['category'] = category;
    data['thumbnail'] = thumbnail;
    data['images'] = images;
    return data;
  }
}

filter_screen.dart

import 'package:b/model.dart';
import 'package:b/services.dart';
import 'package:flutter/material.dart';

class FilterScreen extends StatefulWidget {
  const FilterScreen({super.key});

  @override
  State<FilterScreen> createState() => _FilterScreenState();
}

class _FilterScreenState extends State<FilterScreen> {
  filterProduct() {
    ApiServices().myFilterList().then((value) {
      myItems(value!.products!);
      setState(() {});
    });
  }

  // for filtering the items
  List<Products> filterLists = [];
  List<Products> myItems(List<Products> list) {
    for (var element in list) {
      if (element.rating > 4.7 && element.rating < 5) {
        // show only the items name whose rating is greate then 4.7 and less then 5
        filterLists.add(element);
      }
    }
    return filterLists;
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Filter The Item's From API"),
      ),
      body: ListView.builder(
          shrinkWrap: true,
          itemCount: filterLists.length,
          itemBuilder: (context, index) {
            return ListTile(
              title: Text(
                filterLists[index].title.toString(),
              ),
              subtitle: Text(
                "Rating : ${filterLists[index].rating.toString()}",
              ),
            );
          }),
    );
  }
}

// in ther it showt he product  title whose brand is apple  lets check it  from postman