Gradle Tutorial for Android: Getting Began – Half 1

Replace observe: Ricardo Costeira up to date this tutorial for Android Studio 2023.1.1. Irina Galata wrote the unique.

On this tutorial, you’ll study Gradle and how one can set it up in a maintainable and scalable approach. By the tip of this tutorial, you’ll have the ability to:

1. Construct your Android apps from the command line.
2. Learn each Groovy and Kotlin Gradle construct recordsdata.
3. Handle dependencies with Gradle.

What’s Gradle?

Gradle is an open-source build-automation system. It has the comfort of a Groovy- or Kotlin-based DSL and some great benefits of Ant and Maven. With Gradle, you’ll be able to simply manipulate the construct course of and its logic to create a number of variations of your app. It’s a lot simpler to make use of and much more concise and versatile when in comparison with Ant or Maven alone.

Getting Began

Obtain the starter challenge by clicking the Obtain Supplies hyperlink on the prime or backside of the tutorial.

Open the challenge in Android Studio, and check out its construction within the Mission pane in Android Studio:

Take note of the recordsdata with the Gradle elephant icon and .gradle extension. These recordsdata are generated by Android Studio routinely throughout challenge creation. They’re written in Groovy and accountable for processing your challenge’s construct. They comprise the required information about challenge construction, library dependencies, library variations and the app variations you’ll get on account of the construct course of.

Ranging from Android Studio Giraffe, Kotlin would be the default language for construct configuration. Gradle recordsdata written in Kotlin have the .gradle.kts extension. You may see that there are already a couple of within the challenge, however they had been manually added. These are the Kotlin equal to the .gradle ones. Nicely, kind of — they’re pretty totally different in habits at this level, however you’ll perceive why as you progress by the tutorial.

Exploring the Mission-Degree Information

Discover the construct.gradle file within the root listing of the challenge. It’s referred to as a top-level (project-level) construct.gradle file. It accommodates the settings which can be utilized to all modules of the challenge.

Open the file, and also you’ll see the next code:

// 1
buildscript {
    // 2
    repositories {
        google()
        mavenCentral()
    }
    // 3
    dependencies {
        classpath "com.android.instruments.construct:gradle:8.2.2"
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.20"
    }
}
// 4
allprojects {
    repositories {
        google()
        mavenCentral()
    }
}
// 5
duties.register('clear', Delete) {
    delete rootProject.buildDir
}

Right here’s what’s occurring, step-by-step:

1. Within the buildscript block, you outline settings wanted to construct your challenge.
2. Within the repositories block, you add names of the repositories the place Gradle ought to seek for the plugins you utilize.
3. The dependencies block accommodates obligatory plugin dependencies — on this case the Gradle and Kotlin plugins. Don’t put your module dependencies on this block.
4. The construction of the allprojects block is just like the buildscript block, however right here you outline repositories for your entire modules, not for Gradle itself. Normally you don’t outline the dependencies part for allprojects. The dependencies for every module are totally different and may reside within the module-level construct.gradle.
5. A job represents a bit of labor within the construct course of. This straightforward one cleans up the construct recordsdata when executed. You’ll be taught extra about duties later on this tutorial.

Transferring on to Module-level Information

Now, go to the construct.gradle file within the app module listing. It accommodates dependencies — libraries {that a} module depends on — and directions for the construct course of. Every module defines its personal construct.gradle file.

// 1
plugins {
    id "com.android.utility"
    id "kotlin-android"
}
// 2
android {
    // 3
    namespace "com.kodeco.socializify"
    // 4
    compileSdk 34
    // 5
    defaultConfig {
        // 6
        applicationId "com.kodeco.socializify"
        // 7
        minSdkVersion 23
        // 8
        targetSdkVersion 34
        // 9
        versionCode 1
        // 10
        versionName "1.0"
    }
    // 11
    buildFeatures {
        viewBinding true
    }
    // 12
    kotlin {
        jvmToolchain(17)
    }
}
// 13
dependencies {
    implementation fileTree(embody: ["*.jar"], dir: "libs")
    implementation "androidx.appcompat:appcompat:1.6.1"
    implementation "com.google.android.materials:materials:1.9.0"
}

The code above does the next:

1. Specifies a listing of plugins wanted to construct the module. The com.android.utility plugin is important with a purpose to arrange the Android-specific settings of the construct course of. Right here, you can too use com.android.library in case you’re making a library module. The kotlin-android plugin lets you use the Kotlin language in your module.
2. Within the android block, you place all platform-specific choices of the module.
3. Defining a namespace is important for issues like useful resource entry. This was within the AndroidManifest.xml file beneath the bundle property, however has now migrated.
4. The compileSdk possibility signifies the API degree your app will probably be compiled with. In different phrases, you’ll be able to’t use options from an API increased than this worth. Right here, you’ve set the worth to make use of APIs from Android Tiramisu.
5. The defaultConfig block accommodates choices that will probably be utilized to all construct variations (e.g., debug, launch, and so forth) of your app by default.
6. The applicationId is the identifier of your app. It needs to be distinctive in order to efficiently publish or replace your app on the Google Play Retailer. In case you go away it undefined, the construct system will use the namespace as applicationId.
7. With a view to set the bottom API degree supported, use minSdkVersion. Your app is not going to be out there within the Play Retailer for the gadgets operating on decrease API ranges.
Observe: To get extra acquainted with the Android SDK variations, learn our tutorial overlaying that subject.
8. The targetSdkVersion parameter defines the utmost API degree your app has been examined on. That’s to say, you’re positive your app works correctly on the gadgets with this SDK model, and it doesn’t require any backward-compatibility habits. One of the best method is to completely check an app utilizing the most recent API, preserving your targetSdkVersion worth equal to compileSdk.
9. versionCode is a numeric worth for the app model.
10. versionName is a user-friendly string for the app model.
11. The buildFeatures block permits you to allow sure options, like View binding or Compose. On this case, it’s doing the previous.
Observe: If you wish to be taught extra about View binding, try our tutorial on it.
12. Gradle 8.2 helps JVM 17 by default, so that you pressure the challenge to make use of Java 17 by Gradle’s Java toolchain help.
13. The dependencies block accommodates all dependencies wanted for this module. Later on this tutorial, you’ll discover out extra about managing your challenge’s dependencies.