Gradle build for set of Android projects (including libraries)

Question

I have 2 Android apps with 5 Android modules (Android library project). Total 7 Eclipse projects. I want to enable Gradle build for them. I added build.gradle in the root folder and listed all project in settings.gradle

include ':app1'
include ':app2'
...

However I discovered that I need to copy-paste section below in every one of 7 project

android {
    compileSdkVersion 19
    buildToolsVersion "19.0.3"

    defaultConfig {
        minSdkVersion 1
        targetSdkVersion 19
        versionCode 1
        versionName "1.0"
    }
        ... // and so on like source folders configuration
}

Reason: when I add apply plugin: 'android' inside root build.gradle (see Could not find method android() in root of multimodule project),
then I can't apply plugin: 'android-library' for libraries projects (see https://stackoverflow.com/questions/23864292/minimal-gradle-configuration-for-android-library-in-multimodule-project)

But it is what I want to avoid, having different version of Android and Android tools specified in different places.

How can I minify this configuration to have as many things as possible in one build.gradle config file.

Answer 1

You can use your build.gradle in root, or you can define some values in gradle.properties in root folder to achieve your scope.

For example:

root/build.gradle:

ext {
    compileSdkVersion = 19
    buildToolsVersion = "19.0.3"
}

module/build.gradle:

android {
    compileSdkVersion rootProject.ext.compileSdkVersion
    buildToolsVersion rootProject.ext.buildToolsVersion
}

OR using properties

root/gradle.properties:

VERSION_NAME=1.0.1
VERSION_CODE=11

module/build.gradle:

android {

    defaultConfig {
        versionName project.VERSION_NAME
        versionCode Integer.parseInt(project.VERSION_CODE)

    }

Answer 2

Other option would be as Peter Niederwieser suggested

either add some logic to the root script to apply the right plugin to each subproject (there are different ways to do this), or move the common parts into a script named android.gradle and apply that script to each subproject after applying the correct plugin for that project (all in the subproject's build script).

Related docs is Chapter 56. Multi-project Builds