A Complete Tutorial On Flutter Freezed With Example

One can generate data classes in Dart with the code-generation module Freezed. It prevents users from writing numerous lines full of mistakes. Perhaps all you need is a class with a function Object() { [native code] }, a function toString() { [native code] } function, and perhaps a value property to hold its contents.

Imagine that one wants the pieces to stay in place and offer an additional copyWith function for it. If you are a Flutter coder then, you know how to accomplish all of this in Dart, you are aware that several code lines are required.

A reliable and expandable code writer for data classes is called Freeze. It is dependable but has one drawback: it’s difficult for newbies to locate the ideal combination and essential elements to employ in the application concept. 

Consider it posted as a handful of bulleted lists to reference sometimes because it has excellent information and an in-depth description. The article further outlines several main characteristics that freezed provides and discusses why one requires it.

Freeze: An Overview

The freezed module is a reliable and scalable code generator for data types and union structures. Additionally, it permits serializing and deserializing Metadata. Rémi Rousselet developed freeze as a code editor for invariant systems. One may recognize his name from the package’s names supplier, riverpod, and hooking.

Data modelling is leveraging frozen scripting language codes to create a graphical visualization of the data that characterizes a corporate entity. It is a method which is frequently applied in the majority of situations. A data structure can depict the connections among different business entities. Alternatively, if one is familiar with database systems, one can quickly compare a database schema to a SQL table that defines it and employs fixed coding lines.

Also Read:

How to Freeze Elements to Percentage of Screen Width/Height in Flutter?

Process To Use Freezed: 

Program Setup: First, one must establish a project to use freezed. Please start a new Flutter application in Android Studio by opening it and entering the program’s name, URL, descriptions, and domains. The project includes us selecting the architecture on which it will be executed. After that, we must add a few variables required for the use.

Install: For using Freezed simply, we should first add a few requirements to the task: 

• Build Runner
• Freezed, and 
• Freezed Annotation

Here are the codes:

dev_dependencies:
 flutter_test:
 SDK: Flutter
 build_runner: ^2.1.7
 freezed: ^1.1.1
 freezed_annotation: ^1.1.0

Another command to add up these dependencies:

flutter pub add freezed_annotation
 flutter pub add --dev build_runner
 flutter pub add --dev freezed

Freeze: Model creation uses a freezed bundle. With information, combinations, template matching, and replication, it has a single codebase.

build_runner: Beyond the utilities like the pubs, this build runner module offers a practical method for creating documents utilizing Dart script. In contrast to public build/serve, upgrades are gradual, and documents are often created immediately on disc. This approach was motivated by technologies such as Bazel.

freezed_annotation: For freezed, consider Freezed annotations. With freezed, none of it is done by such a program. The module is required if we wish to utilize Freezed; else, Freezed would not work.

Run the generator:- Run the script to launch a single code. Here is the code: 

flutter pub run build_runner build

Whenever the modules that provide Builder are set up with such a build. yaml file, these are intended to be used with a building code generated automatically. Most developers will require minimal to no configuration; to determine if this is the case, consult the Builder’s manual. 

One can include a build. yaml with the layouts if you wish.

Furthermore, integrate the modules into the dart package with the below-mentioned code. 

import 'package:freezed/builder.dart';

Creating a Model using Freezed:- The first step in utilizing the @freezed annotations when constructing a model is to build a module. 

Flutter App Development designate TestModel{} as the identifier of a module.

import 'package:freezed_annotation/freezed_annotation.dart';
part 'response.freezed.dart';
part 'response.g.dart';
@freezed
 class TestModel{}

Then create the classes with mixins when it is created. The category that multiple categories can utilize without sub-classing is known as a mixin.

import 'package:freezed_annotation/freezed_annotation.dart';
part 'response.freezed.dart';
part 'response.g.dart';@freezed
class TestModel with _$TestModel{}

Next, the business function with the listing of each of the parameters and attributes is added as a function Object() { [native code] }. Within this factory function, derived from “freezed annotation,” it declares @Default. For variables that are not necessary, a default value can be specified using the @Default annotations. Below is the code:

import 'package:freezed_annotation/freezed_annotation.dart';part 'response.freezed.dart';
 part 'response.g.dart';
@freezed
 class TestModel with _$TestModel {
   @JsonSerializable(fieldRename: FieldRename.snake, explicitToJson: true)
   const factory TestModel({
     @JsonKey(name: 'id') int? id,
     @JsonKey(name: 'label') String? label,
     @JsonKey(name: 'image') String? image,
     @JsonKey(name: 'status') int? status,
 
   }) = _TestModel;

Finally, We have developed the function Object() { [native code] }, where one must execute the fromJson and toJson functions. Although fromJson and toJson aren’t developed within the freezed module, it is aware of what JSON serializable represents. Here is the code:

import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'response.freezed.dart';
 part 'response.g.dart';
@freezed
 class TestModel with _$TestModel {
   @JsonSerializable(fieldRename: FieldRename.snake, explicitToJson: true)
   const factory TestModel({
     @JsonKey(name: 'id') int? id,
     @JsonKey(name: 'label') String? label,
     @JsonKey(name: 'image') String? image,
     @JsonKey(name: 'status') int? status,
 
   }) = _TestModel;
 
   factory TestModel.fromJson(Map<String, dynamic> json) =>
       _$TestModelFromJson(json);
 }

One must execute the command to create the response.g.dart and response.freezed.dart files; otherwise, the code would display issues. The next phase is to browse the file containing the application within the console and run the following code. Below is the code mentioned:

flutter pub run build_runner build --delete-conflicting-outputs

Conclusion: 

In this article, we went over how to utilize the Freezed package in Flutter. It demonstrates how and where to utilize it, how much coding will be saved, and how much time can be secured while using freezed. Users can develop a Flutter app and accomplish various tasks by utilizing it. 

There is a documented issue with the combination of JSON serializable and freezed where its dart analysis issues errors over an incorrect annotations source. Everyone who views cautions as flaws must have the freezed packages. The project deployment and coding become quite easy with the Flutter package. 

Frequently Asked Questions (FAQs)

1. What is the use of freezed in Flutter applications?

A Freeze package is utilized to develop the model. It is the code generator for the data classes, unions, and cloning. The build_runner package gives the correct way to generate files using Dart code outside tools such as a pub.

2. What is the freezed annotation in Flutter development?

It is the code generator for the data and union classes which is robust and scalable. It allows serialization and deserialization of the JSON data.

3. Is Flutter enough for front-end development?

Flutter has a cross-platform SDK. It has a strong widgets, tools and libraries that will easily create high-quality mobile apps for any purpose.

Written by Dhara Acharya

Dhara Acharya, with over 5 years of experience, has established herself as a proficient SEO Specialist. Her expertise in enhancing online visibility and driving organic traffic has significantly benefited numerous projects. Dhara's strategic approach and keen insight into search algorithms make her a valuable asset in the digital marketing realm.