Fetch.dart

 
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:pokemonApp/pokemon.dart';
import 'package:pokemonApp/pokemondetails.dart';

void main()=>runApp(MaterialApp(
  title:"poke App",
  home: HomePage(),
  debugShowCheckedModeBanner: false,
  ));

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  var url ="https://raw.githubusercontent.com/Biuni/PokemonGO-Pokedex/master/pokedex.json";
  PokeHub pokeHub;
  @override
  void initState(){
    super.initState();

    fetchData();
  }

  fetchData() async{
    var res = await http.get(url);
    print(res.body);
    var emeka = jsonDecode(res.body);

    pokeHub = PokeHub.fromJson(emeka);
    setState(() {
      
    });
  }
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Poke App"),
        backgroundColor: Colors.cyan
      ),

      body: pokeHub == null ? 
        Center(child: CircularProgressIndicator()):
       GridView.count(
        crossAxisCount: 2,
        children: pokeHub.pokemon.map((poke) => Padding(
          padding: const EdgeInsets.all(8.0),
          child: InkWell(
            onTap: (){
              Navigator.push(context, MaterialPageRoute(builder: (context) => PokeDetail(pokemon: poke)));
            },
            child: Hero(
              tag: poke.img,
              child: Card(
                elevation: 3.0,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                  children: [
                    Container(
                      height: 100,
                      width: 100,
                      decoration: BoxDecoration(
                        image: DecorationImage(
                          image: NetworkImage(poke.img)
                        )
                      ),
                    ),
                    Text(poke.name, style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),)
                  ]
                ),
              ),
            ),
          ),
        )).toList(),),


      floatingActionButton: FloatingActionButton(onPressed: null,child: Icon(Icons.refresh),
        backgroundColor: Colors.cyan,
        ),

      drawer: Drawer(),
    );
  }
}