Flutter Interview Questions

A list of regularly inquired Flutter Interview Questions and Answers are given below. These questions are of a basic level.



Let's get started.

Q.1) What is Flutter?

Flutter is Google's mobile UI framework that provides a fast and expressive way for developers to build native apps on both iOS and Android. This is because apps and interfaces made with Flutter are built from a single codebase, compiled directly to native arm code, use the GPU, and can access platform APIs and services. The first alpha version of Flutter was released in May 2017. It is additionally widely used for building full-featured apps that include, storage, camera, network, geolocation, third party SDKs, and apart more.

Q.2) Is Flutter an Open Source?

Yes, Flutter is open source framework and free.

Q.3) What are widgets in Flutter?

In Flutter, everything is a widget. Widget is immutable. A Flutter app is continuously considered as a tree of widgets. At whatever point you're planning to code for building anything in Flutter, it'll be inside a widget. Widgets describe how your app view should see with their current setup and state. After you made any modification within the code, the widget modified its description by calculating the contrast of past and calculating the contrast of past and current widget to decide the minimal changes for rendering within the app's UI.

Q.4) What is the difference between Stateful and Stateless Widget?

A Stateful widget contains the state information. It is treated as a dynamic one because it changes the internal data during the lifetime of a widget. The basic identification of a Stateful widget is that it permits refreshing the screen. This widget doesn’t have a build() method but it includes a createState() strategy. The createState() method makes a difference in extending the Flutters State Class. Illustrations of Stateful widgets are Slider, Checkbox, Frame, Radio, InkWell, and textFilled.

A Stateless widget does not contain any state information. It'll countinously be static all through its life.  In case a widget or screen contains a substance that's static, it is considered a Stateless widget. You'll be to only modifications to the content within the Stateful mode as it were.  Examples of Stateless widgets are Row, Text, Container, Columns, etc.

Q.5) Name the best editors for Flutter development?

The famous and most using IDE for Flutter development which allow to make development faster and easier are as follows:

  • Android Studio
  • Visual Studio
  • IntelliJ IDEA
  • XCode

Q.6) What is the use of pubspec.ymal file?

It is a configuration file of all flutter projects that helps a lot whenever working with Flutter. This file is sensitive so we have to arrange all the things in proper manner and this file allows you to define constraints for the app. This file contains certain things as follows:

  • Dependencies of project.
  • Assets in the project like audio, images, fonts, etc.
  • There is general settings of a project like description, name, and version of the project.

Q.7) Flutter takes so long time when it is built for the first time. Explain why?

The reason why flutter app take a longer time when building for the first time is that the Flutter built the device specific APK and IPA file. Gradle for android and XCode for iOS are used to build the file, that takes a long time.

Q.8) Flutter and React Native - Which one is best?

The common thing between Flutter and React Native is that are both used to develop the native hybrid app from a single codebase. Apps can run on both the platform, i.e., android and iOS.

Flutter is developed by Google and uses dart language and React Native is developed by Facebook and uses JavaScript. So, both the frameworks has good feature and community.

So, it is difficult for any developers to choose winner among these as they both are on it's high peak.

Q.9) What is Hot Reload in Flutter?

This hot reload feature allows you to quickly and easily perform an experiment in the project as it helps to build the UI faster, fix bugs and make development fast.

Q.10) What are some popular apps made in flutter? Name them.

Many applications have already build in flutter which are so popular and they are:

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

Q.11) What are the advantages of Flutter?

The list given below are the advantages of Flutter.

  • Faster code writing
  • Less Testing
  • One code for two platforms
  • Designs which user will adore
  • Hot Reloading and Hot Restart

Q.12) What is the use of BuildContext in Flutter?

In Flutter, BuildContext is the part of widget used to get the reference to another widget or theme.  For example, if we want to use a material design element, it is required to reference it to the scaffold. We can get it using the Scaffold.of(context) method.

Q.13) What are the different modes you use to build your app?

Basically, there are three modes as follows:

  • Debug Mode - used to debugging code and find out errors.
  • Profile Mode - used to measure the performance of the applications.
  • Release Mode - used when we are ready to release the app.

Q.14) What are the famous database used in Flutter?

  • Firebase database: allows users to access and make changes to the cloud database.
  • sqflite database: allows users to access and make changes to the SQLite database.

Q.15) How many types of List Views in Flutter?

  • ListView
  • seperated
  • builder
  • custom
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