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 manner. 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 the benefits of Ant and Maven. With Gradle, you may 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 high or backside of the tutorial.

Open the challenge in Android Studio, and try its construction within the Challenge pane in Android Studio:

Take note of the recordsdata with the Gradle elephant icon and .gradle extension. These recordsdata are generated by Android Studio mechanically throughout challenge creation. They’re written in Groovy and liable for processing your challenge’s construct. They include the mandatory data 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’ll be able to see that there are already a number of within the challenge, however they have been manually added. These are the Kotlin equal to the .gradle ones. Properly, kind of — they’re pretty totally different in habits at this level, however you’ll perceive why as you progress via the tutorial.

Exploring the Challenge-Degree 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 comprises the settings which are 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 employ.
3. The dependencies block comprises essential 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 all your modules, not for Gradle itself. Often you don’t outline the dependencies part for allprojects. The dependencies for every module are totally different and will 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 study 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 comprises 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.software"
    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.software plugin is important so as to arrange the Android-specific settings of the construct course of. Right here, you may also use com.android.library if you happen to’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 underneath the package deal property, however has now migrated.
4. The compileSdk choice signifies the API degree your app will probably be compiled with. In different phrases, you may’t use options from an API larger than this worth. Right here, you’ve set the worth to make use of APIs from Android Tiramisu.
5. The defaultConfig block comprises 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. If you happen to depart it undefined, the construct system will use the namespace as applicationId.
7. With the intention to set the bottom API degree supported, use minSdkVersion. Your app is not going to be obtainable within the Play Retailer for the gadgets working on decrease API ranges.
Word: To get extra acquainted with the Android SDK variations, learn our tutorial masking that matter.
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 strategy is to totally take a look at an app utilizing the newest API, retaining 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 helps you to allow sure options, like View binding or Compose. On this case, it’s doing the previous.
Word: If you wish to study extra about View binding, take a look at our tutorial on it.
12. Gradle 8.2 helps JVM 17 by default, so that you power the challenge to make use of Java 17 via Gradle’s Java toolchain help.
13. The dependencies block comprises all dependencies wanted for this module. Later on this tutorial, you’ll discover out extra about managing your challenge’s dependencies.