Flutter Top interview questions

Last Updated on 21 Jan 2022 by Satya Prakash Singh Rathour
10 mins read

1. What is Flutter?

 Answer  👉  Flutter is a UI toolkit for creating fast, beautiful, natively compiled mobile applications with one programming language and a single codebase. It is an open-source development framework developed by Google. Generally, Flutter is not a language; it is an SDK. Flutter apps use Dart programming language for creating an app. The first alpha version of Flutter was released in May 2017.

Flutter is mainly optimized for 2D mobile apps that can run on both Android and iOS platforms. We can also use it to build full-featured apps, including camera, storage, geolocation, network, third-party SDKs, and more.


02. What is the Flutter widget?

Answer 👉 In Flutter every component is considered a widget like text, container, row, column, style and so on. A flutter app builds with a widget tree. There are two types of widgets in Flutter, Stateless widgets, and Stateful Widgets.

03. What are the advantages of Flutter?

Answer 👉 Advantages of Flutter are _

  • It's cross-platform so that we can make an app for android, ios, web or even desktop application with a single codebase.
  • Rapid performant application development.
  • Hot and live reloading make app changes easier during development without compromising the application state.
  • Good official documentation.
  • Growing flutter community.
  • It is open-sources and maintained by Google.


04. What is Dart?

Answer 👉  Dart is an open-source object-oriented programming language developed by Google in 2011. Flutter uses Dart language for application development.


05. What is a stateful and stateless widget?

Answer 👉  Stateless Widgets: Stateless widget which does not hold the state information of application and will not rebuild widgets when application state change happened.

Stateful Widgets: Stateful Widgets has the state information of an application and the widgets are rebuilt when a certain application state change occurred.



06. What is the BuildContext in Flutter?

Answer 👉 It's a part of widgets in the element tree. In flutter, every widget has its own build context.


07. What is null safety in Flutter?

Answer 👉  It helps to disappear the null related errors at runtime. From Flutter 2 and dart 2.12, the null safety was introduced. Learn more about Null safety.


08. What is the main difference between Hot restart and Hot reload?

Answer:  👉

Hot reload: It compiles the newly added code and reflect it instantly into UI without changing the application state. Hot reload perform by pressing r in the command prompt.

Hot restart: It completely rebuilds the entire application code by resetting the application state. It takes a longer time than the hot reload. It performed by pressing Ctrl+R.


9) What is pubspec.yaml file?

Answer  👉  It is the project's configuration file that will use a lot during working with the Flutter project. It allows you how your application works. It also allows us to set the constraints for the app. This file contains:

  • Project general settings such as name, description, and version of the project.
  • Project dependencies.
  • Project assets (e.g., images, audio, etc.).


10) Name some popular apps that use Flutter?

Answer  👉 Today, many organizations use Flutter for building the app. Some of the most popular app built on Flutter are as follows:

  • Google Ads
  • Reflectly
  • Alibaba
  • Birch Finance
  • Coach Yourself
  • Tencent
  • Watermaniac


Category: Flutter | App Development

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