Here we’ve collected some of the important flutter interview questions.

What is Dart?
DART is a versatile OOP-based language with C-style syntax. It is a general-purpose open-source programming language and developed and designed by Google in 2011. The main purpose of DART programming is to create a front-end user interface for web and mobile applications. It is an important language for creating flutter-based mobile applications. The DART language can be compiled in both AOT (Ahead-of-Time) and JIT (Just-in-Time) pattern.

What is Flutter?

Flutter is a UI toolkit for building fast, beautiful, and natively compiled mobile apps with a single programming language and single code base. It is an open-source development framework developed by Google. In general, flutter is not a language but an SDK. It uses the Dart programming language to build applications. The alpha version was released in May 2017.
Since then many updates were pushed in the Flutter SDK and the current version (March 2021) is 1.22.
Flutter is primarily optimized for 2D mobile apps which can run on Android and iOS platforms. We can also use it to create complete applications including cameras, storage, geolocation, networks, third-party SDKs, etc.


What are the advantages of flutter ?

The major advantages of the flutter are,

Cross-Platform Development: Flutter allows us to write, maintain, and run code on different platforms at the same time. This saves developers time, effort, and money.
Rapid development: The performance of the pulsed application is rapid. The flutter compiles the application using the C / C ++ library, which brings it closer to machine code and gives the application performance closer to native one.
Good Community: Flutter has a growing and active community , where developers can post problems and get answers quickly.
Live and Hot Reloading: This makes the app development process very fast. This feature allows us to modify or update changes as soon as a change is made.

Minimal Code: The flutter application was developed using the DART programming language, which uses JIT and AOT compilation to improve overall boot time, thus speeding up performance. JIT improves the development system and refreshes the user interface without additional effort in a new version.

UI Focused: It has great UI because it uses a design-focused widget, high development tools, advanced APIs, and many other features. Also, the UI is consistent across different ecosystems.

Documentation: Flutter has very good documentation. It’s systematic and more informative. We can get anything we want to write in one place.

What are widgets in flutter?

A flutter app is always thought of as a tree of widgets. Anytime you’re going to code to create anything in Flutter, it’ll be inside a widget.
Widgets describe what your app’s view should look like with their current configuration and state. When you made changes to the code, the widget recreated its description by calculating the difference between the previous and current widgets to determine the minimum changes for rendering in the app UI.
Widgets go together to create an application. This means that the root of your app itself is a widget, and at the very bottom, there is also a widget. For example, a widget can display something, define the design, manage conversations, etc.

What are stateful and stateless widgets in flutter?

The stateful widget contains the state information. It is qualified as stateful because it can modify the state of the widget during its life cycle. Stateful widgets are those widgets that allow us to change/update a UI dynamically.

It has the createState method to initialize the state of a widget.It returns a class that extends the Flutter’s state class. Examples of stateful widgets are checkbox, radio, cursor, inkwell, form, and text field.

The stateless widget has no state notification. It remains constant throughout the life cycle. Examples of stateless widgets are text, rows, columns, containers, etc. If the screen need to hold static content, it is better to have a stateless widget, but if you want to update the content dynamically, it must be a stateful widget.

What is the purpose of pubspec.yaml file?

This is the project configuration file that will be of great use when working with the Flutter project. It explains how your application works. It also allows us to define constraints for the application. This file contains:
General project settings such as project name, description and version.
Project dependencies.
Project resources (eg images, audio, etc.).
Most of the modern editor supports updating the dependencies and resources dynamically upon modification of this file.

What is the difference between flutter and react native ?

Both Flutter and React Native are used to developing the original hybrid app from a single codebase. An application written in both of them can run on android and iOS.

React Native is developed by Facebook, while the Flutter Framework was initially developed by Google. Thus, both frameworks have very good functionality and a very good community.

Flutter uses the Dart language to build apps, while React uses JavaScript to build native apps.

From the developer’s point of view, it might be difficult to choose between them. But for performance,stability,documentation,Inbuilt widget support and many more, we recommend you to choose the flutter.

What is tween animation in Flutter?

It is abbreviated from “in-between”. In a tweened animation, it is necessary to define the beginning and end of the animation. This means that the animation starts at the initial value, then passes through a series of intermediate values ​​, and finally reaches the final value.

It also provides timelines and curves, which define transition times and speeds. The widget framework provides the mechanism on how to traverse from the initial point to the endpoint.

To be Continued…