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 means. By the top 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 possibly can 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 try 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 chargeable for processing your challenge’s construct. They comprise the mandatory data about challenge construction, library dependencies, library variations and the app variations you’ll get because 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 just a few within the challenge, however they had been manually added. These are the Kotlin equal to the .gradle ones. Effectively, roughly — they’re pretty totally different in conduct at this level, however you’ll perceive why as you progress by way of the tutorial.

Exploring the Mission-Stage Information

Discover the construct.gradle file within the root listing of the challenge. It’s known as a top-level (project-level) construct.gradle file. It accommodates the settings which might 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 happening, 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 needed 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 whole 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 process 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.

Shifting 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(embrace: ["*.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 an inventory of plugins wanted to construct the module. The com.android.utility plugin is important in an effort to arrange the Android-specific settings of the construct course of. Right here, it’s also possible to use com.android.library when you’re making a library module. The kotlin-android plugin permits you to 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 once within the AndroidManifest.xml file below the bundle property, however has now migrated.
4. The compileSdk choice signifies the API stage your app might be compiled with. In different phrases, you possibly can’t use options from an API greater 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 might 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 must be distinctive in order to efficiently publish or replace your app on the Google Play Retailer. In case you depart it undefined, the construct system will use the namespace as applicationId.
7. In an effort to set the bottom API stage supported, use minSdkVersion. Your app won’t be accessible within the Play Retailer for the units working on decrease API ranges.
Be aware: To get extra acquainted with the Android SDK variations, learn our tutorial masking that matter.
8. The targetSdkVersion parameter defines the utmost API stage your app has been examined on. That’s to say, you’re positive your app works correctly on the units with this SDK model, and it doesn’t require any backward-compatibility conduct. The very best strategy is to totally take a look at an app utilizing the newest API, maintaining 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.
Be aware: If you wish to be taught extra about View binding, take a look at our tutorial on it.
12. Gradle 8.2 helps JVM 17 by default, so that you drive the challenge to make use of Java 17 by way of Gradle’s Java toolchain assist.
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.