Interfacing with Websockets and Streams in Dart's Flutter Framework

What Will I Learn?

Write here briefly the details of what the user is going to learn in a bullet list.

• You will learn about asynchronous snapshots
• You will learn how to use the streambuilder widget
• You will learn how to use the websocket channel library from the flutter sdk

Requirements

• IDEA intellij or Visual Studio Code with the Dart/Flutter Plugins
• The Dart SDK and the Flutter SDK
• A fair understanding of Mobile development and Imperative or Object Oriented Programming

Difficulty

• Intermediate

Description

In this Flutter Video Tutorial, we take a look at the Websocket Channel Library and how we can interface with websockets using the Flutter SDK. We also look at the concept of the asynchronous snapshot and the basic idea behind the StreamBuilder widget. We take these concepts and build out a simple echo chat application which fires off a message to a websocket and then receives the message back as an echo.

The Websocket Channel Library gives us an abstraction that is above streams; a StreamChannel. This StreamChannel wraps the websocket connections in a Sink and a Stream. The Sink handles sending messages and the stream handles receiving messages. We can use the Stream in our Stream Builder Widget by accepting the data in Asynchronous Snapshots. These Snapshots are a central concept in Dart; the idea that we can save state and data as a pool of bytes. This idea originally came from one of Dart's predecessor languages, Smalltalk. Dart uses Snapshots in its virtual machine and in different parts of the language for many different reasons. In this case we are using them to gain access to incremental data cross-sections from our stream.

The source code for this project can be found here

The echo websocket server we used in this tutorial can be found here

Video Tutorial

Projects and Series

Stand Alone Projects:

• Dart Flutter Cross Platform Chat Application Tutorial
• Building a Temperature Conversion Application using Dart's Flutter Framework
• Managing State with Flutter Flux and Building a Crypto Tracker Application with Dart's Flutter Framework

Building a Calculator

• Building a Calculator Layout using Dart's Flutter Framework
• Finishing our Calculator Application with Dart's Flutter Framework

Movie Searcher Application

• Building a Movie Searcher with RxDart and SQLite in Dart's Flutter Framework (Part 1)
• Building a Movie Searcher with RxDart and SQLite in Dart's Flutter Framework (Part 2)
• Building a Movie Searcher with RxDart and SQLite in Dart's Flutter Framework (Part 3, Final)

Minesweeper Game

• Building a Mine Sweeper Game using Dart's Flutter Framework (Part 1)
• Building a Mine Sweeper Game using Dart's Flutter Framework (Part 2)
• Building a Mine Sweeper Game using Dart's Flutter Framework (Part 3)
• Building a Mine Sweeper Game using Dart's Flutter Framework (Part 4, Final)

Curriculum

• Building a Multi-Page Application with Dart's Flutter Mobile Framework
• Making Http requests and Using Json in Dart's Flutter Framework
• Building Dynamic Lists with Streams in Dart's Flutter Framework
• Using GridView, Tabs, and Steppers in Dart's Flutter Framework
• Using Global Keys to get State and Validate Input in Dart's Flutter Framework
• The Basics of Animation with Dart's Flutter Framework
• Advanced Physics Based Animations in Dart's Flutter Framework
• Building a Drag and Drop Application with Dart's Flutter Framework
• Building a Hero Animation and an Application Drawer in Dart's Flutter Framework
• Using Inherited Widgets and Gesture Detectors in Dart's Flutter Framework
• Using Gradients, Fractional Offsets, Page Views and Other Widgets in Dart's Flutter Framework
• Making use of Shared Preferences, Flex Widgets and Dismissibles with Dart's Flutter framework
• Using the Different Style Widgets and Properties in Dart's Flutter Framework
• Composing Animations and Chaining Animations in Dart's Flutter Framework
• Building a Countdown Timer with a Custom Painter and Animations in Dart's Flutter Framework
• Reading and Writing Data and Files with Path Provider using Dart's Flutter Framework
• Exploring Webviews and the Url Launcher Plugin in Dart's Flutter Framework
• Adding a Real-time Database to a Flutter application with Firebase
• Building a List in Redux with Dart's Flutter Framework
• Managing State with the Scoped Model Pattern in Dart's Flutter Framework
• Authenticating Guest Users for Firebase using Dart's Flutter Framework
• How to Monetize Your Flutter Applications Using Admob
• Using Geolocator to Communicate with the GPS and Build a Map in Dart's Flutter Framework
• Managing the App Life Cycle and the Screen Orientation in Dart's Flutter Framework
• Making use of General Utility Libraries for Dart's Flutter Framework

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