Gradle is more than just an ANT replacement for building Android projects. It aims to make code and resource reuse easy through dependencies, create multiple app variants through flavors and build customization, and integrate well with IDEs. Gradle uses Groovy and allows customizing builds through tasks, dependencies, flavors, and build configurations to generate different APKs for debugging, releasing, and distributing through markets.

1. Gradle not just an ANT
replacement

2. Goals of Gradle (from official docs)
● Make it easy reuse code and resources (.aar)
● Make it easy to create several variants of an application
● Make it easy to configure, extend and customize the
build process
● Good IDE integration

3. About Gradle
●
Is based on groovy:
○ binary-compatible with java
○ Most java code is syntactically valid on Groovy
○ The gradle installation comes with groovy
●
You better use a gradle wrapper for your
android projects

4. Android Studio
● If something goes wrong, use gradle on the command
line
● use this button:
● One update can “break” your project
● If something goes wrong, use gradle on the command
line

5. Basic gradle config
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'com.android.tools.build:gradle:0.6.0+'
}
}
apply plugin: 'android'
android {
compileSdkVersion 19
}

6. Adding libs
dependencies {
//
MavenCentral deps
compile 'com.android.support:support-v4:19.0.0'
compile 'com.android.support:appcompat-v7:19.0.0'
compile 'com.squareup.retrofit:retrofit:1.2.2'
compile 'com.squareup.okhttp:okhttp:1.2.1'
//
project dep:
compile project(“:libraries:lib1”)
//
jar dep:
compile files(‘libs/a.jar”, “libs/b.jar”)
compile fileTree(dir: “libs”, include: “*.jar”)
}

7. Basic gradle commands
$ gradle tasks
$ gradle tasks --all
$ gradle assembleDebug
$ gradle assembleRelease
$ gradle clean
$ gradle installDebug
$ gradle uninstallAll

8. Gradle build customization
android {
compileSdkVersion 19
defaultConfig {
versionCode 1
versionName "1.0"
minSdkVersion 16
targetSdkVersion 16
}
}

9. Build Types
buildTypes {
debug {
packageNameSuffix ".debug"
}
release {
runProguard true
proguardFile getDefaultProguardFile('proguard-androidoptimize.txt')
}
}
$ gradle installFreeDebug

10. Build Variants
productFlavors {
free {
packageName "com.bitcoinlab.android.free"
buildConfig “public static final boolean FULL_VERSION =
false;”
}
full {
packageName "com.bitcoinlab.android.full"
versionName "2.0"
versionCode 20
buildConfig “public static final boolean FULL_VERSION =
true;”
signingConfig signingConfigs.myConfig
}
}

11. Build Variants specific files & deps
src/full/java/src/”packagename”/file.java
src/full/res/values/strings.xml
src/full/AndroidManifest.xml
dependencies {
fullCompile ‘com.squareup.okhttp:okhttp:1.2.1'
}
A source file can’t exists on main src folder and at
the same time on a flavour src folder: put a class into
main, or in every buildType but not both.

12. BuildConfig
import java.text.SimpleDateFormat
def buildTime() {
def df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'")
df.setTimeZone(TimeZone.getTimeZone("UTC"))
return df.format(new Date())
}
defaultConfig {
buildConfig """
public static final String GIT_SHA = "${gitSha()}";
public static final String BUILD_TIME = "${buildTime()}";
"""
}

13. Android Studio Integration

14. Some things you can do with gradle
●
free/paid apk
●
debug/release version
●
beta/alpha/”any git branch” apk
●
Use multiple flavors + multiple-apk play store support to distribute
smaller apks (depending on screen size or android version)
●
build your customized integration and test server in minutes

15. Oriol Jiménez
@oriolj
oriolj@gmail.com