Small introduction to gradle for android

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