How to make runProguard work for the android-library Gradle plugin?

Question

I would like to run ProGuard on release build of my Android library. Below is my build.gradle file that is within my project.

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.5.+'
    }
}

apply plugin: 'android-library'

repositories {
    mavenCentral()
}

android {
    compileSdkVersion 18
    buildToolsVersion "18.0.1"

    defaultConfig {
        minSdkVersion 10
        targetSdkVersion 18
    }

    sourceSets {
        main {
            java {
                srcDir 'src/main/java'
            }
            resources {
                srcDir 'src/../lib'
            }
        }
    }

    buildTypes {
        release {
            runProguard true
            proguardFile getDefaultProguardFile('proguard-android.txt')
        }
    }
}

Running gradlew clean or gradlew build returns the following error:

> Could not find method buildTypes() for arguments [build_25r1m0a3etn5cudtt5odlegprd$_run_closure2_closure10@5f3306ad] on project

It seems that plugin android-library is missing the buildTypes method. If I change apply plugin to android, gradlew runs successfully. However, this is a library project and I would like to keep it so. Other parts my my gradle.build (not mentioned here) rely on the project being a library.

Is there any way to make the android-library plugin run ProGuard on build?

Answer 1

Solved my issue by taking release out of buildTypes like so:

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.5.+'
    }
}

apply plugin: 'android-library'

repositories {
    mavenCentral()
}

android {
    compileSdkVersion 18
    buildToolsVersion "18.0.1"

    defaultConfig {
        minSdkVersion 10
        targetSdkVersion 18
    }

    sourceSets {
        main {
            java {
                srcDir 'src/main/java'
            }
            resources {
                srcDir 'src/../lib'
            }
        }
    }

    release {
        runProguard true
        proguardFile getDefaultProguardFile('proguard-android.txt')
        proguardFile 'proguard-android.txt'
    }
}

Also note that I added another proguardFile under release. This fixed another issue I was having after solving the initial buildTypes problem.