What this PR does?

• Add question on data-flow in stateful widgets
• Add question on InheritedWidgets
• Add question on FAB usage
• Add question on Dart Future

Note

The aim is to help learner prepare for questions around data-flow in stateful widgets, InheritedWidgets and Futures

Cleaned up grammar. Removed:

• What is the role of a ChangeNotifierProvider?
• What is a ValueListenableBuilder? Because these are questions about the provider library and not about Flutter.

Deleted duplicate questions

Effective Dart: Style Linter rule

In new code, use lowerCamelCase for constant variables, including enum values.

In existing code that uses ALL_CAPS_WITH_UNDERSCORES for constants, you may continue to use all caps to stay consistent.

[class Internal extends StatefulWidget{

      @override
      _InternalState createState()=>_InternalState();
    
    }
    class _InternalState extends State<Internal> {
    
      bool isSearching=false;
      Photo(int number,){
        return Scaffold(
          backgroundColor: Color(0XFFfffafa),
          body: SafeArea(
          child: SingleChildScrollView(
            child: Container(
              child: Stack(
                children: <Widget>[
                  Container(
                    height: 19,
                    child: Padding(
                      padding: const EdgeInsets.only(right:360.0),
                      child: IconButton(icon: Icon(Icons.arrow_back,color: Colors.black,size: 30,), onPressed: (){
                        Navigator.push(
                          context,
                          MaterialPageRoute(builder: (context) => Internal()),
                        );
    
                      }),
                    ),
                  ),
                Title1(number),
                ClipRRect(
                  borderRadius: BorderRadius.only(topRight: Radius.circular(40.0),topLeft: Radius.circular(40.0)),
                  child: Image(image:  AssetImage('images/song$number.jpg'),),
                ),
                ],
              ),
            ),
          ),
        ),
    Title1(int number){
      number=1;
      Container(
        margin: EdgeInsets.only(left:37.0,right: 37,bottom: 10),
        child: Center(child: Text('Tempo : 102\nStyle : Waltz\nChord : C\nTranspose : 4',
          style: TextStyle(color: Colors.white,fontFamily: 'SourceSansPro',fontWeight: FontWeight.w600,fontSize: 20),)),
        height: 120.0,
        width: 380,
        decoration: BoxDecoration(shape: BoxShape.rectangle,color: Color(0XFF40404F),borderRadius: BorderRadius.circular(20.0)),
      );
      number=2;
      Container(
        margin: EdgeInsets.only(left:37.0,right: 37,bottom: 10),
        child: Center(child: Text('Tempo : 102\nStyle : Waltz\nChord : C\nTranspose : 2',
          style: TextStyle(color: Colors.white,fontFamily: 'SourceSansPro',fontWeight: FontWeight.w600,fontSize: 20),)),
        height: 120.0,
        width: 380,
        decoration: BoxDecoration(shape: BoxShape.rectangle,color: Color(0XFF40404F),borderRadius: BorderRadius.circular(20.0)),
      );
    }
    );
  }

import 'dart:io';    
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_app_retrofit/example.dart';

class Homepage extends StatefulWidget {
@override
HomepageState createState() => HomepageState();
}

class _HomepageState extends State<Homepage> {
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: Center(
child: FutureBuilder(
future: this._getPosts(),
builder: (context, snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
return CircularProgressIndicator();
break;
case ConnectionState.waiting:
return CircularProgressIndicator();
break;
case ConnectionState.active:
return CircularProgressIndicator();
break;
case ConnectionState.done:
return CircularProgressIndicator();
break;

default:
return CircularProgressIndicator();
     }
   },),
 ),
);
}

Future _getPosts() async {
final dio= Dio();
(dio.httpClientAdapter as DefaultHttpClientAdapter).onHttpClientCreate = await (client) async {
SecurityContext securityContext=new SecurityContext();
final ByteData crtData = await rootBundle.load('assets/server.crt');
securityContext.setTrustedCertificatesBytes(crtData.buffer.asUint8List());
final ByteData keyBytes = await rootBundle.load('assets/server.key');
securityContext.usePrivateKeyBytes(keyBytes.buffer.asUint8List());
return HttpClient(context: securityContext);
};
final client = RestClient(dio);
client.login('madhusudhan@****.in', '88888');

}}

In flutter we are getting using Dio. I am getting a error using Dio The problem is here that i need to use SSl certificate So i used Dio But now i am getting the below error. Unhandled exception Future is not a subtype of HttpClient.