Using Gradle | Build Tools | Kotlin Tutorial

Introduction to Gradle

Gradle is an open-source build automation tool that is designed for multi-project builds. It uses a Groovy-based domain-specific language (DSL) to define the build logic, allowing developers to manage dependencies, compile source code, package binaries, and deploy applications. Gradle is particularly popular in the Kotlin and Android development communities.

Installing Gradle

Before you can use Gradle, you need to install it on your system. You can install Gradle manually or use a package manager.

To install Gradle manually, follow these steps:

Download the latest Gradle distribution from the Gradle Releases page.
Unzip the downloaded file to a location on your machine.
Add the Gradle bin directory to your system's PATH environment variable.

To verify the installation, run the following command:

gradle -v

Output:

------------------------------------------------------------

Gradle 7.5.1

------------------------------------------------------------

Creating a New Gradle Project

To create a new Gradle project, you can use the Gradle Wrapper or initialize it manually. The Gradle Wrapper is a script that allows you to run Gradle tasks without requiring the user to install Gradle themselves.

To initialize a new project using the Wrapper, navigate to your desired project directory and run:

gradle init

Follow the prompts to set up your project. This will create the necessary directory structure and files.

Understanding the Build File

Gradle uses a file named build.gradle to define the build logic. This file is written in Groovy or Kotlin DSL. Here is a basic example of a build.gradle file for a Kotlin project:


                plugins {

                    id 'org.jetbrains.kotlin.jvm' version '1.5.30'

                }

                repositories {

                    mavenCentral()

                }

                dependencies {

                    implementation 'org.jetbrains.kotlin:kotlin-stdlib:1.5.30'

                }

This example specifies the Kotlin plugin, declares a repository for dependencies, and adds the Kotlin standard library as a dependency.

Building the Project

Once your build.gradle file is set up, you can build your project using the following command:

gradle build

This command compiles the source code, runs tests, and packages the application.

Running the Project

To run your Kotlin application, you can use the run task defined in the application plugin. First, add the following to your build.gradle:


                plugins {

                    id 'application'

                }

                mainClassName = 'com.example.MainKt'

Now you can run your application with:

gradle run

Managing Dependencies

Gradle makes it easy to manage dependencies. You can specify libraries your project needs in the dependencies block of your build.gradle. For example:


                dependencies {

                    implementation 'com.squareup.okhttp3:okhttp:4.9.1'

                    testImplementation 'junit:junit:4.13.2'

                }

In this example, we added OkHttp as an implementation dependency and JUnit as a test dependency.

Conclusion

Gradle is a powerful and flexible build tool that helps manage the build lifecycle of your projects, especially in Kotlin development. By following the steps outlined in this tutorial, you can set up a Gradle project, manage dependencies, and build your application efficiently.