1. Why is Flutter for mobile app developing tools?

Flutter is a free and open-source mobile UI framework, introduced by Google in May 2017. Flutter enables you to develop a native mobile app using only one codebase. This implies you may design two separate apps using the same programming language and codebase (for iOS and Android).

Flutter is preferred over other mobile app development tools like Java and React Native due to a myriad of reasons. A few of them are:

• Flutter supports cross-platform development
• Programming in Flutter is extremely easy and flexible
• The building process in Flutter is much faster than that in all its competitors

2. What are packages and plugins in Flutter?

A package is a set of classes, interfaces, and sub-packages that allow users to create modular code that can be shared easily. Instead of starting from scratch, using packages can help construct applications fast. In Flutter, you may use a package to add new widgets or functionality to an app.

On the other hand, a plugin is a piece of software that enhances your app’s functionality. Plugins play a crucial role in the Flutter ecosystem.

3.What are the limitations of Flutter?

Since Flutter is still a relatively new tool, it has some limitations. They are as follows:

• The number of third-party libraries is very small
• The release size of Flutter is larger than expected
• Flutter requires to be used along with another OOP language, Dart which cannot compete with other OOP languages such as Java, C#
• Due to Flutter’s limited complexity, mobile ad platforms do not support it
• Flutter is still not used by a wide audience

4. Why does it generally take a long time to develop a Flutter app?

Because Flutter generates a device-specific IPA or APK file, building a Flutter application takes substantially longer the first time. This method, which normally takes a long time, uses Xcode and Gradle to build a file.

5. What are keys and how do you use them?

A set of IDs for Widgets, Elements and SemanticsNodes make up the key class. Keys are responsible for preserving the state of widgets when they are updated inside the widget tree. Keys may also be used to modify and rearrange collections of widgets of the same type and defined states.

Otherwise, keys may be superfluous to the code, even if they aren’t harmful in any manner. Keys are useful when you need to edit a widget tree with stateful widgets, but not when the tree is entirely made up of stateless widgets.

6. What are the different types of streams in Dart?

Streams provide an asynchronous sequence of data. Asynchronous programming uses the idea of streams. They refer to a program’s asynchronous succession of data occurrences. We put a value on one end and a listener on the other, similar to a pipe. Several listeners can be combined into a single stream, and when they are placed in the pipeline, they will all get the same data. It is possible to utilize the SteamController to establish new streams or manage existing ones. There are two types of streams:

• Single Subscription Streams These streams convey events in chronological order. They’re thought of as individual sequences inside a greater totality. When the sequence in which events are received matters, such as when reading a file, these streams are employed. Throughout the sequence, there can only be one listener, and the event will not be triggered if there isn’t one.
• Broadcast Streams These broadcasts provide subscribers with information about upcoming events. Subscribers can instantly begin listening to events after subscribing to them. These are flexible streams that allow several listeners to listen at the same time. Furthermore, even after canceling a previous membership, one may listen again.

7. What is pubspec.yaml file?

While creating a Flutter project, a particular type of file is always included at the top of the project. This file is known as the pubspec.yaml file, also called ‘pubspec’. This file contains information about a project’s dependencies, such as packages and their versions, typefaces, and so on. It ensures that the package version is the same the next time you create the project. You can also place restrictions on the app. This project’s configuration file will be used a lot while working with the Flutter project. This specification is written in YAML, a human-readable markup language.

8. What is Flutter?

Flutter is an open source software development kit (SDK) UI used for cross-platform applications from a single codebase. Flutter is primarily used for creating natively compiled, multi-platform applications across iOS and Android seamlessly.

9. Flutter is developed by which company?

Google

10. What was the first version of Flutter which ran on an Android operating system?

Sky is the first version of Flutter which ran on Android OS. It was announced at the 2015 Dart developer summit with the stated goal of being able to render consistently at 120 frames per second.

11. Can you tell us the four main elements of Flutter?

The four main elements of Flutter are:

• Flutter engine
• Widgets
• Design-specific widgets
• Foundation Library

12. When was the first version of Flutter released?

The first version of Flutter was released in May 2017, but it was first announced in 2015. In December 2018, Google released Flutter 1.0. In December 2019, Flutter 1.12 was released.

13. Flutter is written in which language?

Flutter was written in the Dart language. While writing and debugging an application, Flutter runs in the Dart virtual machine, which features a just-in-time execution engine.

14. What does the acronym SDK stand for?

Software Development Kit is a set of software tools and programs provided by software and hardware vendors that developers can use to develop applications for specific platforms. An SDK helps developers easily integrate their apps with a vendor’s services. SDKs can include APIs(Application Programming Interfaces), sample code, documentation, and other resources that help developers create software applications.

15. Can you name some best editors for Flutter development?

Some popular IDEs (Integrated Development Environment) for Flutter include the following:

• Android Studio
• IntelliJ Idea
• Emac
• Visual Studio
• Codemagic

16. Which operator is used to evaluate and return values between two expressions?

This “??” operator is used to evaluate and return values between two expressions. This operator first checks the expression 1 and, if it is non-null, returns its value; otherwise, it will evaluate and return the value of expression 2.

17. Can you tell us how many kinds of widgets there are in Flutter?

There are two main types of widgets in Flutter. These include:

StatelessWidget– It does not have any state information. It is static throughout its lifecycle. Examples are Row, Text, Column, and Container.

StatefulWidget– It has state information. It contains two classes: the state object and the Widget. It is dynamic because it can change the inner data during the Widget’s lifetime. Examples are Radio, Form, Checkbox, and TextField.

18. Can you name the command used to compile the release mode?

This command “Flutter run — release” is used to compile the release mode. Release mode for a web app means that the app is compiled with the dart2js compiler for best performance.

19. Name the different types of build modes in Flutter.

There are three types of build modes in Flutter. These include:

Debug– It is used to test the apps. On Android Studio, you can find a green play button on the top panel. “Flutter run”

Profile– In this mode, some debugging ability is maintained – enough to profile your app’s performance, and also, it has the performance as the release mode. “Flutter run — profile”

Release– It is used for deploying the app on marketplaces. “Flutter run – – release”

20. Which widget in Flutter is a box that comes with a different size?

SizedBox is a widget in Flutter that allows us to specify an arbitrary size for a widget. It is basically used to add empty space between widgets. SizedBox also supports specifying a specific aspect ratio for its child.