Anatomy of a Gradle file

Motivation

Understanding Gradle is mandatory if you want to build good Android apps

Bare Minimum

This is the bare minimum you need to be able to compile and run an Android application:

plugins {
    id 'com.android.application'
    id 'kotlin-android'
}

android {
    compileSdk 30

    defaultConfig {
        applicationId "de.creatronix.myapplication"
        minSdk 21
    }
    
}

dependencies {
    implementation 'androidx.core:core-ktx:1.6.0'
}

Let’s dissect the parts

Plugins

Plugins are programs which extend the gradle build process

When you need special feature like annotation processing the Plugin goes here

What is kapt?

Android

In this section you define for which specific android version you are developing:

minSdk means that your app isn’t supported on devices with an API level below.

targetSdk is the preferred Android version you like to run on

You can add buildTypes section to distinguish between release and debug builds.

In the release build you can e.g. enable the minification

How to enable R8 in your build process

What is ProGuard?

How to fix android.view.InflateException: Error inflating class fragment

Depencencies

Dependencies come in many flavors:

implementation

These are dependencies which are needed to run the application

Until gradle 7.0 these dependencies were called “compile”. Now they are deprecated, so use implementation

testImplementation

The dependency is only available in the test source set.

androidTestImplementation

The dependency is only available in the androidTest source set.