whatsupcoders/flutter-interview-questions

This repo contains a list of helpful Flutter related questions you can use to interview potential candidates.

Flutter Interview Questions

This file contains a number of Flutter interview questions.

Note: Keep in mind that many of these questions are open-ended and could lead to interesting discussions.

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Title: Flutter Interview Questions

• What is the difference between a StatelessWidget and a StatefulWidget in Flutter?
• Explain the Stateful Widget Lifecycle?
• When do you use the WidgetsBindingObserver?
• What is Flutter tree shaking?
• What is a Spacer widget?
• What is the difference between hot restart and hot reload?
• What is an InheritedWidget? List some examples.
• Why is the build() method on State and not StatefulWidgets?
• What is a pubspec file in Dart?
• How is Flutter native?
• What is a Navigator and what are Routes in Flutter?
• What is a PageRoute?
• Explain async, await and Futures.
• How can you update a ListView dynamically?
• What is a Stream?
• What are keys in Flutter and when should you use it?
• What are GlobalKeys?
• When should you use mainAxisAlignment and crossAxisAlignment?
• When can you use double.INFINITY?
• What is Ticker, Tween and AnimatedBuilder?
• What is ephemeral state?
• What is an AspectRatio widget used for?
• How would you access StatefulWidget properties from its State?
• Is there a suggested limit to the number of FloatingActionButtons a screen can have? Give a reason(s) for your answer
• Mention two or more operations that would require you to use or return a Future.
• What is the purpose of a SafeArea?
• When to use a mainAxisSize?
• SizedBox VS Container?
• List the Visibility widgets in flutter and the differences?
• Can we use Color and Decoration property simultaneously in the Container? Explain
• Inorder for the CrossAxisAlignment.baseline to work what is another property that we need to set?
• when should we use a resizeToAvoidBottomInset?
• What is the difference between 'as','show' and 'hide' in an import statement?
• What is the importance of a TextEditingController?
• Why do we use a Reverse property in a Listview?
• Difference between a Modal and Persistent BottomSheet with an example?
• How is an Inherited Widget different from a Provider?
• What is an UnmodifiableListView?
• Difference between these operators "?? and ?."
• What is the purpose of ModalRoute.of()?
• Difference between a Navigator.pushNamed and Navigator.pushReplacementNamed?
• Difference between a Single Instance and Scoped Instance ?

Title: Animation Interview Questions

• What is a vsync?
• When does the animation reach completed or dismissed status?
• Difference between `AnimationController and Animation?
• When to use a SingleTickerProviderStateMixin and TickerProviderStateMixin?
• Define a TweenAnimation ?
• State the importance of a Ticker ?
• Why do we need a mixins ?

Title: FireStore Interview Questions

• Difference between getDocuments() vs snapshots()?

Getting Involved

1. How to Contribute
2. License

Contributors:

This project is currently maintained by:

• @whatsupcoders

Feeling inspired? Check our Contributing guide to get started!

flutter-interview-questions's Issues

I am new to flutter and i am developing flutter app I want to call a function inside the column but it said null values.i have tried to show the Title1() function inside the Photo() class but it shows error.

[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)),
      );
    }
    );
  }

Answers?

Maybe someone could answer those questions :)

This could become the best flutter interview preparation source.

Future<HttpClient> is not a subtype of HttpClient

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.

Categorize Questions based on Developer Level

Hey @whatsupcoders

I was wondering if we can categorize the questions based on the developer level. From my experience, not all questions are made for Junior developers. However, this is open to suggestions.

I am looking at the following category:

1. Senior Developer
2. Junior Developer

Thanks.