Flutter Interview Questions and Answers

It doesn’t matter if you’re a fresher or an experienced professional; you need the right skills and knowledge to land your dream job. The process begins with an understanding of the interview questions that will be asked. This blog aims to help professionals grow their careers as Flutter developers.

Are you gearing up for a Flutter interview? Exciting times are ahead! To help you shine in your interview, we’ve compiled a collection of meticulously crafted Flutter interview questions and expertly curated answers. From widgets to navigation, state management to Firebase integration, prepare to showcase your Flutter prowess and leave a lasting impression on your potential employers. Let’s embark on this knowledge-packed journey and unlock the doors to your fluttering success!

Table of Content

• Questions for Freshers
• Questions for Experienced

Flutter Interview Questions for Freshers

1. What is Flutter?

Flutter is an open-source UI Software Development Kit (SDK) created by Google. It enables developers to build natively compiled applications for mobile, web, and desktop from a single codebase. Flutter uses the Dart programming language and offers a rich set of pre-designed widgets that help create visually appealing and consistent user interfaces across platforms. Its “hot reload” feature facilitates rapid development and experimentation. By using Flutter, developers can streamline the process of creating high-performance, cross-platform apps with a cohesive look and feel. It makes it a popular choice for building versatile and efficient applications.

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2. Is Flutter an SDK?

Yes, Flutter is an SDK (Software Development Kit). It provides a comprehensive set of tools, libraries, and frameworks that developers use to build applications. The Flutter SDK includes everything needed to create, compile, and run Flutter applications, along with a rich collection of pre-designed widgets, APIs, and development tools. This SDK allows developers to write code once and deploy it on multiple platforms, such as mobile, web, and desktop, making the development process more efficient and streamlined.

3. What are the Reasons for Using Flutter?

Using Flutter to create mobile apps has several benefits: –

Less coding time: Hot Flutter’s Reload feature makes things run faster. For quicker app development, the app is written in C/C++ code to make it as similar to machine code as feasible. Hence, the availability of widgets in Flutter reduces writing time and uses reusable code.

Cross-platform development: Using Flutter code on another platform will save the developers’ time.

Performs like a Native App: Flutter code is as near to machine code as possible and functions like a native program. This lessens errors brought on by incorrect code interpretation.

Minimal Code: The Dart programming language creates the Flutter app. This accelerates development, and the user interface loads quickly. Dart uses highly quick JIT and AOT compilation.

Customized designs: Personalized layers allow for the creation of customized designs, quicker rendering, and creative user interfaces.

Must read- What is Programming?

4. What kinds of applications can I develop with Flutter?

Flutter is made to handle both interactive apps that you wish to operate on your web pages or on the desktop and mobile apps that run on both Android and iOS.

Know more about programming languages for android app development

Flutter is incredibly well suited for apps that must give highly branded designs. However, Flutter allows you to produce pixel-perfect experiences that adhere to the iOS and Android design languages.

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An extensive range of hardware (including camera, GPS, network, and storage) and services are supported via the package ecosystem of Flutter (such as payments, cloud storage, authentication, and ads).

Check out- Android app development Online Courses & Certifications

5. What is Flutter Architecture?

Flutter architecture comprises three layers:

Upper layer- The platform built using Dart that handles app widgets, gestures, animations, drawings, and materials.

Flutter engine- Manages the display and text formatting.

Built-in service: Manages event loops, packages, and plugins.

Check out: Build Native Mobile Apps with Flutter

6. What are the different build modes in Flutter?

Debug mode: Switch to debug mode when using hot reload during development.

Profile mode: Use profile mode when you wish to evaluate performance.

Release mode: Use release mode when your app is ready for distribution.

7. Which technology is used by Flutter?

C, C++ the 2D rendering engine Skia, and the object-oriented language Dart are all used to create Flutter.

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8. Name some popular apps that use Flutter.

It is used in the development of several popular apps. Some of the apps are:-

• Tencent
• Alibaba
• Reflect
• Google Ads
• Birch Finance

9. What is Dart?

An object-oriented programming language similar to the C Language is called Dart. In 2011, Google created this open-source language. The language was designed specifically for front-end coding of mobile applications. You can code the user interface on the front end using the application. Applications created with Flutter use the Dart programming language.

Read out: Top 10 Most-Popular Programming Languages to Learn

10. What do Flutter packages and plugins do?

Packages are groups of related classes, interfaces, and sub-packages, whether Flutter or any other object-oriented language. The usage of plugins and packages helps developers write code more quickly. Additionally, the coder can use packages and plugins to avoid writing the code from scratch for every task.

The differences between plugins and packages are negligible. A package is a new component or code written in Dart. In contrast, plugins use native code to enable extra functionality. Despite their slight differences, the two names are occasionally used interchangeably.

Questions for Experienced

1. Which is better, Flutter or React?

• While Google first introduced the Flutter framework, Facebook developed React Native. Therefore, both frameworks have excellent features and communities.
• While React Native builds its apps using JavaScript, Flutter employs the Dart programming language.
• The native hybrid app is created using Flutter and React Native from a single codebase. Both the iOS and Android platforms support these apps.

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It is challenging for the developer to select one of them. So picking a winner between Flutter vs Native is quite difficult.

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2. Why BuildContext?

Widgets in widget trees can be recognized or located using build contexts. There is one BuildContext for each widget or one BuildContext overall. We use it to look up references to other widgets and themes. Additionally, you can use it to communicate with widget parents and have access to widget data.

3. What are the points of difference between runApp() and main() in Flutter?

Main()

When rendering the widget tree on the screen, it returns the widgets connected to the screen as the widget tree’s root.

Primary function refers to the function that drives the app

RunApp()

It is a feature that is used to launch the software. You cannot create any program in Flutter without the main() function.

4. Explain the Primary Axis and Cross Axis Alignment

Our preferences determine how a row and column widget aligns with its children using the CrossAxisAlignment and PrimaryAxisAlignment.

PrimaryAxisAlignment

In PrimaryAxisAlignment, the columns run vertically while the rows run horizontally.

CrossAxisAlignment

In CrossAxisAlignment, the columns run horizontally while the rows run vertically.

5. What are the keys fluttering, and where should developers apply them?

In Flutter, widgets, elements, and semantic nodes are identified by keys. The subclasses of Key are GlobalKeys and LocalKeys. Keys in the widget tree are in charge of keeping modified widgets in their original state. You can also rearrange and change collections of widgets having the same type and state using keys. Flutter developers can use keys to alter a widget tree that includes stateful widgets rather than a tree entirely made up of stateless widgets.

6. What is the purpose of using Mixins?

The Dart language does not enable multiple inheritances. You require mixins to implement multiple inheritances in Flutter/Dart. When you use mixins, it becomes accessible to write reusable class code at different levels of the class hierarchy. Mixins (such as RenderSliverHelpers in Flutter) can also provide several utility functions.

7. Describe the Flutter Provider.

Widgets are used to construct the provider. With the new widget subclasses it generates, you may utilize every object in the provider as if they were only a component of Flutter. Additionally, this indicates that the service could be more cross-platform. The most straightforward approach to state management is through the provider. It operates via the PUB-SUB principle. Therefore, in other words, there is only one provider and many subscribers.

8. How are Containers and SizedBoxes different?

Container: By effectively modifying their size, padding, and color, several child widgets in this parent widget can be readily controlled and handled. If a widget requires styling, such as a specific color, shape, or size, we can wrap it in a container widget.

SizedBox: This is a box of a particular size. All that is necessary in this situation is scaling the widget supplied as a child. In other words, it strictly limits the size of its child widget.

9. How can you create an HTTP request in Flutter?

Use the HTTP package (import ‘package: HTTP/HTTP.dart’ as HTTP;) To create HTTP requests. In the following manner, we can make the Requests:

HTTP.get(‘https://jsonplaceholder.typicode.com/albums/1‘);  

It will return a Future <http.Response>.

10. Different types of streams in Dart

Single-Subscription Streams: Single-subscription streams allow only one listener at a time. They emit asynchronous events over time.
Broadcast Streams: Broadcast streams allow multiple listeners to subscribe simultaneously. They broadcast events to all active listeners.
StreamController: StreamController is used to create and control streams. It allows adding events to the stream and closing the stream.
Future-based Streams: Dart can convert a Future into a stream using the asStream method. It allows working with asynchronous operations that return a single value as a stream.
StreamTransformers: StreamTransformers are used to transform and manipulate streams. Built-in transformers like map, where, expand, etc., modify the emitted events of a stream.
StreamSubscription: When you listen to a stream, you receive a StreamSubscription object. It represents an active subscription to a stream and provides methods to handle events, cancel the subscription, or pause/resume listening.

11. When do you utilize profile mode, and what does it do?

We employ profile mode to gauge how well our programs are working. In this mode, you can profile your app’s performance while debugging. The emulator and simulator have this setting disabled since they don’t accurately reflect real-world performance.

Use the command below to compile the profile mode:

flutter run --profile   

12. When do you utilize release mode, and what does it do?

Release mode enables us to thoroughly optimize the codes and produce them without any debug data. There will be many rewrites or eliminations in the code of the application. When the app is ready for release, we operate in this mode. Additionally, it allows for maximum optimization and a small application footprint.

Run the command below to compile the release mode,

flutter run --release

12. 

Wrapping It Up!!

You can ace the interview and land your desired job using these Flutter interview questions and answers. You should also increase your understanding of the field to comprehend shifting trends and obtain new data. Also, ensure you concentrate on something other than the Flutter interview questions. Moreover, you can check various Flutter-related certifications and courses to brush up on your concepts in a better way.