Flutter Interview Questions & Answers

Flutter Interview Questions

Outline

This is a comprehensive guide on Flutter interview questions. It has three sets of important Flutter interview questions and answers: Beginners, Intermediate and Advanced.

With the help of our sure-fire Flutter interview preparation guide, you can ace your upcoming interview and land your dream position as a Flutter developer.

Introduction - Flutter Interview Questions and Answers

The next revolution in the mobile space is flutter, which is exploding. It has demonstrated the ability to surpass all current mobile technologies and take the lead as the sole option for cross-platform app development in the future.

Flutter provides free and open-source UI development help and was first created by Google before being handled by ECMA. With the help of this UI toolkit, users can build stunning, natively generated mobile applications using only one programming language and one codebase.

You may create mobile applications for iOS and Android using a framework like Flutter that is entirely platform-independent. It is regarded by developers as the quickest and most expressive approach to create native apps. Flutter will soon have a big influence on the creation of top-notch, feature-rich mobile applications because to its simplicity, excellent performance as a result of its development, and rich user interface.

Optymize is a US-based company with global clients. We offer 100% remote opportunities as well as competitive payments. Sign up with us, crack the interview and work with Fortune 500 Companies.

Flutter Interview Questions for Beginners

1. How many types of widgets are there in Flutter?

There are two kinds of widgets:
-StatelessWidget : This widget does not require mutable state.
-StatefulWidget: This widget that has a mutable state.

2. What are the different build modes in Flutter?

Debug Mode This mode makes it possible to debug programmes on a real device, an emulator, or a simulator. Here, both service extensions and assertions are permitted. Compilation is then optimised to enable rapid deployment.

Profile Mode While testing the programme, some debugging capabilities are still available, allowing for performance analysis. In this situation, tracing and certain extensions are enabled. Profile mode is not enabled on emulators and simulators because of how inaccurately they mimic real-world performance. The profile mode may be built with the following command: run flutter–profile

Release Mode This mode is utilised while delivering the software to reduce footprint size and increase optimization. Here, assertions, debugging, and service extensions are all deactivated. Its primary benefits are quicker startup, quicker execution, and smaller size. The release mode may be built with the following command: run flutter–release

3. Explain the flutter widget and write its importance.

A Flutter app typically consists of a variety of widgets. User interfaces may be declared and built using widgets. To develop anything with Flutter, you must write code inside a widget. You may use the widget to check how your app would look in its present setup. The modifications will sync with the UI of the app as soon as you make a change to the code since the widget will immediately construct its description based on the differences between the old and new widget. This is how the Flutter widget may be made:

Class ImageWidget extends StatelessWidget { // Class Stuff }

The widgets used to build the app are nested one inside the other. As a result, your app’s root and all child widgets are also widgets.

4. Explain App state.

A shared state or application state are other names for app state. Sharing app states across different parts of your app while preserving user sessions is feasible. Here are a few App State instances:

-Login info
-User preferences
-E-commerce shopping cart
-Social networking notifications, etc

5. Write the difference between runApp() and main() in flutter.

main(): This procedure launches the application. Without the main() method, Flutter does not allow us to build any programmes.

runApp(): The widgets that are linked to the screen may be returned using runApp() and used as the root of the widget tree that will be shown on the screen. The main function, which serves as the app’s driver, calls this function.

6. Define Dart?

Dart is an object-oriented, general-purpose programming language with C-like syntax. It was created by Google in 2011 and is freeware. The frontend user experience for mobile and online apps will be created using the Dart programming language.

7. Explain Flutter Inspector.

React determines if a real DOM update is required when a component’s props or state change by comparing the newly returned element with the previously displayed one. React updates the DOM if they are not equal. Reconciliation is the name given to this procedure.

Intermediate Flutter Interview Questions

With practice, you will be able to respond to basic Flutter interview questions with ease as a developer.

We have gathered some challenging Flutter interview questions for you in this part. You can get assistance from this section with these precise types of intermediate Flutter interview questions you might face while looking for work.

1. What function does Ticker provide in Flutter?

In Flutter, we track how frequently our animation is updated using a ticker. This kind of signal-sending class sends signals at a fixed frequency, such as 60 times per second. With the help of our perpetually ticking watch, we can better comprehend it. A callback method is offered for each tick and contains the time since the first tick at the second it was initiated. Even if the tickers start at separate times, they instantly synchronise.

2. What use do Mixins serve?

The Dart language does not enable multiple inheritances. In order to implement multiple inheritances in Flutter/Dart, mixins are required. Writing reusable class code at different levels of the class hierarchy is simple when mixins are used. Additionally, several utility functions can be provided using mixins (such as RenderSliverHelpers in Flutter).

3. Why do you use the term "streams" in Flutter?

Streams are used in asynchronous programming to deliver a succession of data in an asynchronous way. We set a value on one end and a listener gets it on the other, much like a pipe. When inserted in the pipeline, several listeners can be combined into one stream and receive the same data. Through the SteamController, streams may be created and managed.

The await for and listen() methods are available in the Stream API for processing streams. There are several methods to build streams, but only one way to use them.

4. Write the distinction between Hot restart and Hot reload.

The first execution of any dart programme takes a substantial amount of time. Flutter offers two capabilities called Hot Reload and Hot Restart that help fix this issue by shortening the time our app takes to execute after being launched.

Hot Reload It is regarded as a good attribute of flutter that it does its duty in around one second. You may quickly and simply add functionality, develop UIs, resolve errors, and make modifications with this method. We may rapidly build the new code in a file and transmit it to the Dart Virtual Machine by exploiting the hot reload functionality (DVM). DVM changes the app’s UI as soon as the update is finished. In a hot reload, the saved state is not lost.

Hot Restart Compared to a hot reload, its functionality is a little bit different. The saved states of our software are lost in this process, and the code is rebuilt from scratch. It takes longer than a hot reload, but it completes more quickly than a full restart function.

5. Explain BuildContext.

Widgets in widget trees can be recognised or located using build contexts. There is one BuildContext for each widget, or one BuildContext overall. In essence, we use it to look for references to other widgets and themes. You may use it to communicate with widget parents and have access to widget data.

6 . How does state management work?

State Management is essential whether you are creating a web application or a mobile application. It handles data flow throughout an application by centralising the states of numerous UI components. It can take the shape of a text field, radio button, checkbox, dropdown menu, toggle, or other object. State management in Flutter may be divided into two categories as follows:

Ephemeral State Ephemeral state, which is related to a specific widget, is also known as UI state or local state. In other words, it is a state that the particular widget itself contains. StatefulWidget, a component of Flutter, supports this state.

App State This is distinct from the ephemeral state since it is a state that we wish to share across various app components and keep throughout sessions. Thus, these kinds of states are applicable everywhere. Flutter offers support for this state via scoped model.

5. Explain pubspec.yaml file.

The file that is included when you create a Flutter project that is found at the top of the project tree is called pubspec.yaml, sometimes known as “pubspec.” This file includes details on the dependencies that a project needs, such as packages and their versions, typefaces, etc. It ensures that you will have the same package version the following time you create the project. You can also impose restrictions on the app. This project’s configuration file will be essential while dealing with the Flutter project.

Advanced Flutter Interview Questions

This section contains some advanced interview questions for Flutter jobs. Read and Understand how these complex technologies work and how they help businesses.

1. What would happen if you just ran code in debug mode?

To execute the code just in debug mode, we first need to import the Dart Foundation: import ‘package:flutter/foundation.dart’ as Foundation; The next step is to use kReleaseMode as follows:
if (Foundation.kReleaseMode){ // is Release Mode??
print(‘release mode’); }
else {
print(‘debug mode’); }

2. What is await in Flutter? Write it's usage.

The process flow is halted by await until the async procedure completes. Generally speaking, await implies to wait until this function completes so that you may retrieve its return value. Only async may be used with await. By doing this, all active processes are suspended till the PF nature is finished.

3. Compare SizedBox with Container.

Container: Multiple child widgets in this parent widget may be simply managed and controlled by effectively modifying their size, padding, and colour. If a widget requires style, such as a certain colour, shape, or size, we can wrap it in a container widget.

SizedBox: This box has a particular size. In contrast to Container, it does not let us customise the widget’s colour or decorations. In this instance, all that is necessary is to resize the widget that was sent as a child. In other words, it imposes a certain size requirement on its child widget.

4. How can we create HTTP requests in Flutter?

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

Use the HTTP package to generate HTTP requests by using (import ‘package:http/http.dart’ as https;). We can submit the requests in the way described below:

http.get(‘https://jsonplaceholder.typicode.com/albums/1‘); The response will be a Future .

5. What does a flutter's container class represent?

A widget that can hold several child widgets and manage them effectively using dimensions, padding, and background colour is known as a container class in the flutter framework.

6. What is an AspectRatio widget used for?

The AspectRatio Widget searches for the ideal size to preserve aspect ratio while adhering to its layout restrictions. You may change the aspect ratio of widgets in your app with the AspectRatio Widget.

6. What is a Spacer widget?

Spacer uses a flex container to control the white space between widgets. We may manage the space equally with the Row and Column MainAxis alignment.

6. What are GlobalKeys?

GlobalKeys may be used to obtain data about another widget on a completely other branch of the widget tree or to allow widgets to swap parents anywhere in your app without losing state. If you wanted to display the same widget on two distinct screens while maintaining the same state, for instance, you would want to use a GlobalKey.

6. What is a Flutter inspector?

The Flutter Inspector is a tool for examining and visualising widget trees. It aids in comprehending the current layout and detects numerous layout problems.

Conclusion

Whether you’re a developer getting ready for an interview or a hiring manager trying to find the ideal candidate, we believe these Flutter interview questions and answers will be a tremendous help to you during the process .

Keep in mind that technical proficiency is only one aspect of the hiring process. Both prior experience and soft skills are essential if you want to be hired for a high-paid web development position.

Keep in mind that many of the Flutter interview questions are open-ended. Not just the answer you memorised, but also your reasoning will be of interest to the interviewer. Always be prepared to address any follow-up inquiries about how you came to your conclusion. Describe the way you think.

Good Luck! Regarding your future Flutter interview. You can browse through our listings for Flutter developer jobs here.