This document discusses building Android apps with Gradle. It introduces the motivation for moving to Gradle from Ant and the Eclipse ADT plugin by describing requirements for customization and support across IDEs and CI servers. Key aspects of Gradle covered include the Android plugin, build variants, product flavors, and customizing the build configuration. Demos show how to manipulate tasks and work with variants. The document also briefly outlines testing, dependencies, and ongoing work.

2. BUILDING ANDROID APPSBUILDING ANDROID APPS
WITH GRADLEWITH GRADLE
GREACH 2015, Madrid
René Gröschke
Principal Engineer Gradleware

3. INTRO, DEMO & FORECASTINTRO, DEMO & FORECAST

4. WHY A NEW BUILDWHY A NEW BUILD
SYSTEM?SYSTEM?

5. GRADLE 2.3GRADLE 2.3
RELEASED 16TH FEBRUARY 2015RELEASED 16TH FEBRUARY 2015

6. OLD ANDROID BUILDSOLD ANDROID BUILDS
Two (official) build mechanism
ADT (Eclipse based)
Ant
Maven
Customization?
Nothing in ADT
Manually hacking xml in ant scripts

7. REQUIREMENTS OF THEREQUIREMENTS OF THE
NEW BUILD SYSTEMNEW BUILD SYSTEM
Use same system for
CommandLine
CI Server
IDE
Support for application/library variants
Dependency Management
Provide a plugin ecosystem

8. WHY GRADLEWHY GRADLE
Allows custom DSL to express build logic
Very flexible for customization
Well integrated with CI ecosystem (Ant, Maven, Ivy, CI
server)
Allow User / 3Party tools to configure, extend and
customize the build process
Tooling API for IDE integration
...

9. GRADLE IN A NUTSHELLGRADLE IN A NUTSHELL
apply plugin:'java'
version = file("version.txt").text
task helloWorld << {
println "Hello World - version '$version'!"
}

10. THE ANDROID GRADLE PLUGINTHE ANDROID GRADLE PLUGIN
MINIMAL ANDROID BUILDMINIMAL ANDROID BUILD
plugins {
id 'com.android.application' version '1.1.+'
}
android {
compileSdkVersion 22
buildToolsVersion '22.0.1'
}
>gradle check assemble
>gradle build

11. THE ANDROID GRADLE PLUGINTHE ANDROID GRADLE PLUGIN
BASIC BUILD CUSTOMIZATIONBASIC BUILD CUSTOMIZATION
android {
compileSdkVersion 22
buildToolsVersion '22.0.1'
defaultConfig {
versionCode 12
versionName "2.0"
minSdkVersion 19
targetSdkVersion 22
multiDexEnabled = true
}
}

12. THE ANDROID GRADLE PLUGINTHE ANDROID GRADLE PLUGIN
REMEMBER, IT'S GROOVY!REMEMBER, IT'S GROOVY!
def calculateVersionName() {
...
}
android {
compileSdkVersion 22
buildToolsVersion '22.0.1'
defaultConfig {
versionName calculateVersionName()
}
}

13. BUILD TYPESBUILD TYPES
"controls how an app is built"
Customize app parameters
debuggable flag
native debug compilation flag
package suffix
debug signing
proguard options
2 default types (debug + release)
Source code + resources overlay
Custom dependencies

14. PRODUCT FLAVORSPRODUCT FLAVORS
"a way to generate several versions of the same app"
Customize app parameters
package name
min/targetSdkVersion
versionCodeName
signing info
Source code + resources overlay
Custom dependencies

15. BUILD VARIANTSBUILD VARIANTS
"a variant is always a flavor + a type"
debug release
free free-debug free-release
payed payed-debug payed-release

16. BUILD VARIANTS IIBUILD VARIANTS II
PRODUCT FLAVOR GROUPSPRODUCT FLAVOR GROUPS
debug release
free x86 free-x86-debug free-x86-release
ARM free-ARM-debug free-ARM-release
payed x86 payed-x86-debug payed-x86-release
ARM payed-ARM-debug payed-ARM-release

17. FLAVOR GROUPSFLAVOR GROUPS
flavorDimensions "group1", "group2"
productFlavors {
arm {
flavorDimension "group1"
}
x86 {
flavorDimension "group1"
}
free {
flavorDimension "group2"
}
pro {
flavorDimension "group2"
}
}

18. SOURCE CODE + RESOURCES OVERLAYSOURCE CODE + RESOURCES OVERLAY
~/dev/androidApp/src>tree
|____main
| |____java
| |____res
|____androidTest
| |____java
| |____res
|____free
| |____java
| |____res
|____debug
| |____java
~/dev/androidApp/src>
Build Type > Product Flavor > main

19. DEMO IDEMO I
VARIANTS IN ACTIONVARIANTS IN ACTION

20. BUILD CUSTOMIZATION IBUILD CUSTOMIZATION I
DEX CONFIGURATIONDEX CONFIGURATION
android {
dexOptions {
incremental true
preDexLibraries = false
jumboMode = false
}
}

21. BUILD CUSTOMIZATION IIBUILD CUSTOMIZATION II
AAPT CONFIGURATIONAAPT CONFIGURATION
android {
aaptOptions {
noCompress 'foo', 'bar'
ignoreAssetsPattern "!.svn:!.git:!.ds_store:!*.scc"
}
}

22. BUILD CUSTOMIZATION IIIBUILD CUSTOMIZATION III
AND MOREAND MORE
lint
java compile options
proguard

23. DEMO IIDEMO II
MANIPULATING TASKSMANIPULATING TASKS

24. TESTINGTESTING
no separate test project needed
variant aware tests
run against (all) connected devices
experimental unit test support (android build tools 1.1)
android {
// ...
testOptions {
unitTests.returnDefaultValues = true
}
}

25. PLENTY OF MORE THINGSPLENTY OF MORE THINGS
android libraries (aar)
vivid plugin ecosystem
crashlytics
roboelectrics
testfairy
instabug
...

26. UNDER CONSTRUCTIONUNDER CONSTRUCTION
NDK support
variant aware dependency management
significant performance improvements

27. LINKS AND POINTERSLINKS AND POINTERS
http://tools.android.com/tech-docs/new-build-
system/user-guide
https://groups.google.com/forum/#!forum/adt-dev
gradle.org
gradleware.com
https://github.com/breskeby/android-demo-app

28. Q&AQ&A

30. ¡MUCHAS¡MUCHAS
GRACIAS!GRACIAS!
! @breskeby
" github.com/breskeby
# rene.groeschke@gradleware.com