How to call API (Error)

 main.dart

import 'package:flutter/material.dart';

import 'HomePage.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {

  const MyApp({Key? key}) : super(key: key);

  @override

  Widget build(BuildContext context) {

    return MaterialApp(

      title: 'Github App',

      theme: ThemeData(

        primarySwatch: Colors.deepPurple,

      ),

      home: HomePage(title: 'Parse JSON Data'),

    );

  }

}

HomePage.dart

Error is in getjsondata() in uri 

import 'package:flutter/material.dart';

import 'dart:async';

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

import 'dart:convert';

class HomePage extends StatefulWidget {

  final String title;

  //HomePage({Key? key, @required this.title}) : super(key: key);

  const HomePage({

    Key? key,

    required this.title,

  }) : super(key: key);

  _HomePageState createState() => _HomePageState();

}

class _HomePageState extends State<HomePage> {

  final String url = "https://api.github.com/users";

  List<String> data = [];

  var isLoading = false;

  @override

  void initState() {

    super.initState();

    this.getjsondata();

  }

  Future<String> getjsondata() async {

    var response = await http.get(

      Uri.encodeFull(url),

    );

    //print(response.body);

    setState(() {

      var convertDatatoJson = json.decode(response.body);

      data = convertDatatoJson;

      print(data);

    });

  }

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar: AppBar(

        title: Text(widget.title),

      ),

      body: ListView.builder(

        itemCount: data.length,

        itemBuilder: (BuildContext context, int index) {

          return Card(

            child: Column(

              crossAxisAlignment: CrossAxisAlignment.stretch,

              children: <Widget>[

                ListTile(

                  leading: Icon(Icons.person),

                  title: Text(

                    data[index]['login'],

                    style: TextStyle(fontSize: 20.0),

                  ),

                  subtitle: Text(

                    data[index]['url'],

                    style: TextStyle(fontSize: 10.0),

                  ),

                ),

              ],

            ),

          );

        },

      ),

    );

  }

}