Category: Flutter Interview Question

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

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.

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.

The four main elements of Flutter are:

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

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.

Google

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.

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.

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.

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.