Uri Concatenate and Future

Question

import 'package:http/http.dart' as http;
import 'package:teste3/Post.dart';
import 'dart:convert';
import 'dart:async';
 
class Consumo extends StatefulWidget {
  const Consumo({Key? key}) : super(key: key);
 
  @override
  State<Consumo> createState() => _ConsumoState();
}
 
class _ConsumoState extends State<Consumo> {
 
 
  var _urlBase = Uri.parse("https://jsonplaceholder.typicode.com");
 
  Future<List<Post>> _recuperarPostagens() async {
 
    http.Response response = await http.get( _urlBase + "/posts" );
    var dadosJson = json.decode( response.body );
 
    List<Post> postagens = [];
    for( var post in dadosJson ){
 
      print("post: " + post["title"] );
      Post p = Post(post["userId"], post["id"], post["title"], post["body"]);
      postagens.add( p );
 
    }
    return postagens;
    //print( postagens.toString() );
 
  }
 
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
  appBar: AppBar(
    title: Text("Teste"),
  ),
      body: FutureBuilder<Map>(
        future: _recuperarPostagens(),
        builder: (context, snapshot){
          switch(snapshot.connectionState){
            case ConnectionState.none:
            case ConnectionState.waiting:
              print("conexao waiting");
              break;
            case ConnectionState.active:
            case ConnectionState.done:
              print("conexao done");
              if(snapshot.hasError){
              }else {
 
 
 
              }
          }
          return Center(
            child: Text("teste"),
          );
        },
      )
    );
  }
}

Console Error:

Error: The operator '+' isn't defined for the class 'Uri'.

• 'Uri' is from 'dart:core'.

Try correcting the operator to an existing operator, or defining a '+' operator.

http.Response response = await http.get( _urlBase + "/posts" );

and:

Error: The argument type 'Future<List>' can't be assigned to the parameter type 'Future<Map<dynamic, dynamic>>?'.

• 'Future' is from 'dart:async'.

• 'List' is from 'dart:core'.

• 'Post' is from 'package:mood3/Post.dart' ('lib/Post.dart').

• 'Map' is from 'dart:core'.

    future: _recuperarPostagens(),
  
            ^
  

Can somebody help me?

Answer 1

Try this:

const String _baseUrl = 'jsonplaceholder.typicode.com';
Uri uri = Uri.https(_baseUrl, '/posts');
final response = await http.get(uri);

Answer 2

You cannot concatenate Uris with the '+' operator.

Change

var _urlBase = Uri.parse("https://jsonplaceholder.typicode.com");

to

String _urlBase = "https://jsonplaceholder.typicode.com";

and change

http.Response response = await http.get( _urlBase + "/posts" );

to

http.Response response = await http.get( Uri.parse('$_urlBase/posts') );

Or as Richard suggested refactor your code to use the https named constructor api.dart.dev/stable/2.16.2/dart-core/Uri/Uri.https.html