Android Library - publishing to Maven (THE SILVER BULLET)

[ THE SILVER BULLET ]

This is used for my blog post about publishing Android apps. Start reading here:
https://angrybyte.me/post/174861019530/android-libraries-how-to-1

[master] projectRoot > .travis.yml

# Basic runner configuration
os: linux
language: android
sudo: false # Required for the new container-based infrastructure setup
branches:
  except:
  - release

# Setup environment variables
# ************************************************************** #
#                                                                #
# Don't forget to check versions in 'projectRoot > build.gradle' #
#                                                                #
# ************************************************************** #
env:
  global:
    - PLATFORM_TOOLS=27.0.1
    - BUILD_TOOLS=27.0.3
    - COMPILE_SDK=27

# Enable only JDK 8, source does not build with JDK 7
addons:
  apt:
    packages:
      - oracle-java8-installer
jdk: oraclejdk8

# Pre-configuration step (accept all licenses manually)
install:
  - echo y | android update sdk -u -a -t tools
  - echo y | android update sdk -u -a -t platform-tools
  - echo y | android update sdk -u -a -t build-tools-${BUILD_TOOLS}
  - echo y | android update sdk -u -a -t android-${COMPILE_SDK}
  - echo y | android update sdk -u -a -t extra-google-m2repository
  - echo y | android update sdk -u -a -t extra-android-m2repository
  - echo y | android update sdk -u -a -t extra-google-android-support

# Configure Android
android:
  # Auto-accept these licenses
  licenses:
    - 'android-sdk-preview-license-.+'
    - 'android-sdk-license-.+'
    - 'google-gdk-license-.+'
    - '.+'

  # Build script config
  components:
    - tools # Workaround part 1: Get the new `repository-*.xml`
    - tools # Workaround part 1: Install latest Android SDK tools
    - build-tools-${BUILD_TOOLS}
    - platform-tools

    # Compile SDK
    - android-${COMPILE_SDK}

    # Additional components
    - extra-google-m2repository
    - extra-android-m2repository
    - extra-google-android-support

# Use Gradle's cache (unlock on start)
before_cache:
  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
  - rm -rf $HOME/.gradle/caches/*/plugin-resolution/
cache:
  apt: true
  directories:
    - $HOME/.gradle/caches/
    - $HOME/.gradle/wrapper/
    - $HOME/.android/build-cache

# Execute the script
script:
  - ./gradlew clean
  - ./gradlew build
  - ./gradlew assemble
  # if you want to test: - ./gradlew demo:check
  # if you want a test report: - ./gradlew build jacocoTestReport

# If you're tracking code coverage, then start CodeCov bash script when done with everything
# after_success:
  # - bash <(curl -s https://codecov.io/bash)

[release] projectRoot > .travis.yml

# Basic runner configuration
os: linux
language: android
sudo: false # Required for the new container-based infrastructure setup
branches:
  only:
    - release

# Setup environment variables
# ************************************************************** #
#                                                                #
# Don't forget to check versions in 'projectRoot > build.gradle' #
#                                                                #
# ************************************************************** #
env:
  global:
    - PLATFORM_TOOLS=27.0.1
    - BUILD_TOOLS=27.0.3
    - COMPILE_SDK=27
    - ANDROID_TARGET=android-22 # Enable for connected checks on emulators (Google doesn't support Linux ARMv7 emulation for SDK 23+)
    - ANDROID_ABI=armeabi-v7a # Enable for connected checks on emulators
    - ADB_INSTALL_TIMEOUT=15 # Wait up to 15 minutes for adb to connect to the emulator

# Enable only JDK 8, source does not build with JDK 7
addons:
  apt:
    packages:
      - oracle-java8-installer
jdk: oraclejdk8

# Pre-configuration step (accept all licenses manually)
install:
  - echo y | android update sdk -u -a -t tools
  - echo y | android update sdk -u -a -t platform-tools
  - echo y | android update sdk -u -a -t build-tools-${BUILD_TOOLS}
  - echo y | android update sdk -u -a -t android-${COMPILE_SDK}
  - echo y | android update sdk -u -a -t extra-google-m2repository
  - echo y | android update sdk -u -a -t extra-android-m2repository
  - echo y | android update sdk -u -a -t extra-google-android-support
  - echo y | android update sdk -u -a -t addon-google_apis-google-${COMPILE_SDK}

# Configure Android
android:
  # Auto-accept these licenses
  licenses:
    - 'android-sdk-preview-license-.+'
    - 'android-sdk-license-.+'
    - 'google-gdk-license-.+'
    - '.+'

  # Build script config
  components:
    - tools # Workaround part 1: Get the new `repository-*.xml`
    - tools # Workaround part 1: Install latest Android SDK tools
    - build-tools-${BUILD_TOOLS}
    - platform-tools

    # Compile SDK
    - android-${COMPILE_SDK}
    # Emulator SDK
    - ${ANDROID_TARGET}

    # Additional components
    - extra-google-m2repository
    - extra-android-m2repository
    - extra-google-android-support

    # To run emulator(s) during tests, enable some of these: (Linux ARMv7 goes up to 22 only)
    # - sys-img-armeabi-v7a-android-22
    # - sys-img-armeabi-v7a-android-21
    # - sys-img-armeabi-v7a-android-19
    # - sys-img-armeabi-v7a-android-14
    # - sys-img-armeabi-v7a-android-9
    - sys-img-${ANDROID_ABI}-${ANDROID_TARGET} # Configurable system image

# Use Gradle's cache (unlock on start)
before_cache:
  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
  - rm -rf $HOME/.gradle/caches/*/plugin-resolution/
cache:
  apt: true
  directories:
    - $HOME/.gradle/caches/
    - $HOME/.gradle/wrapper/
    - $HOME/.android/build-cache

# Start up the emulator
before_script:
  - echo no | android create avd --force -n test -t $ANDROID_TARGET --abi $ANDROID_ABI
  - emulator -avd test -no-skin -no-audio -no-window &
  - android-wait-for-emulator
  - adb shell setprop dalvik.vm.dexopt-flags v=n,o=v
  - adb shell input keyevent 82 & # Unlock emulator if locked
# Execute the script
script:
  # Build and prepare
  - ./gradlew clean
  - ./gradlew assemble
  - ./gradlew app:check
  - ./gradlew build
  # if you want a test report: - ./gradlew build jacocoTestReport

  # To run device Android (and CodeCov) tests, enable these lines (requires an Android emulator):
  - ./gradlew assembleAndroidTest
  - ./gradlew connectedCheck

# If you're tracking code coverage, then start CodeCov bash script when done with everything
# after_success:
  # - bash <(curl -s https://codecov.io/bash)

# Setup the deployment step (only on release branches) - upload to GitHub Releases and Bintray
before_deploy:
  - ./gradlew clean blinkerview:install blinkerview:bintrayUpload
  - ./gradlew clean assemble
deploy:
  provider: releases
  api_key: ${GITHUB_OAUTH_TOKEN}
  file_glob: true
  file: app/build/outputs/apk/*
  skip_cleanup: true
  overwrite: true
  on:
    tag: true
    branch: release
after_deploy:
  - echo "Deployment finished."

projectRoot > app > build.gradle

apply plugin: 'com.android.application'

android {
    // versions are declared in projectRoot > build.gradle
    compileSdkVersion COMPILE_SDK
    buildToolsVersion BUILD_TOOLS

    defaultConfig {
        // app ID should also be an external variable if you plan to change it
        // in my case, I don't change it ever (since it's a demo app)
        applicationId "me.angrybyte.blinkerdemo"
        // versions are declared in projectRoot > build.gradle
        minSdkVersion MINIMUM_SDK
        targetSdkVersion TARGET_SDK
        versionCode VERSION_CODE
        versionName VERSION_NAME
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    // this is a demo app only, don't worry about signing :)
    signingConfigs {
        release {
            keyAlias SIGNING_NAME
            keyPassword SIGNING_NAME
            storeFile file('../signing/keystore.jks')
            storePassword SIGNING_NAME
        }
    }

    // CI note: specific options for TravisCI emulators (they take a while to start)
    adbOptions {
        timeOutInMs 20 * 60 * 1000 // 20 minutes
        installOptions "-d", "-t"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }

    // if you don't support Java 8 sugar, you can just delete this block 
    // but you really should look into supporting it
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    
    // versions are declared in projectRoot > build.gradle
    implementation "com.android.support:appcompat-v7:$APPCOMPAT"
    // this one should also go outside if you plan on changing it ever (I don't)
    implementation 'com.android.support.constraint:constraint-layout:1.1.0'

    // to use your library as a local dependency (before uploading): 
    implementation project(':blinkerview')

    // to use your library as a remote dependency (after uploading):
    // and also change the package to be external if you plan on using this (I don't)
    // implementation "me.angrybyte.blinkerview:blinkerview:$VERSION_NAME"
}

projectRoot > build.gradle

buildscript {
    // repositories to fetch plugins from
    repositories {
        google()
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.3'
    }
}

// you may need to use the old syntax here for older Gradle versions (see the dependencies block above)
plugins {
    id "com.github.dcendents.android-maven" version "2.1" // used for generating Maven files
    id "com.jfrog.bintray" version "1.8.0" // used for uploading to Bintray/jCenter (sync to MavenCentral is automatic)
}

// repositories to fetch module dependencies from
allprojects {
    repositories {
        google()
        jcenter()
        mavenCentral()
    }
}

// external variables, available outside of this file (i.e. in module config files)
ext {
    // CI note: if changed, cherry-pick to 'release' branch to auto-deploy
    // only *git tagged* commits on release branch will get deployed
    VERSION_CODE = 101
    VERSION_NAME = "1.0.1"
    SIGNING_NAME = "blinkerview"

    // CI note: don't forget to update this config in: '.travis.yml'
    BUILD_TOOLS = "27.0.3"
    MINIMUM_SDK = 15
    COMPILE_SDK = 27
    TARGET_SDK = 27

    // app/library module dependency versions
    APPCOMPAT = "27.1.1"
    // ESPRESSO = "2.2.2"
    // JUNIT = "4.12"
    // ROBOLECTRIC = "3.3.2"
    // anything else you might need
}

projectRoot > gradle > gradle-mvn-push.gradle

// apply the two plugins, one for generating Maven files, one for uploading to Bintray
apply plugin: 'com.jfrog.bintray'
apply plugin: 'com.github.dcendents.android-maven'

// *****************************************************************************************************
// NOTE: Configuration constants come from gradle.properties, local.properties and environment variables
// *****************************************************************************************************

// sets the project version
version = VERSION_NAME
group = GROUP

// Bintray deployment config
def projectName = project.rootProject.name
def localPropertiesName = 'local.properties'
def isLocalBuild = project.rootProject.file(localPropertiesName).exists()
def uploadConfig = [
        user       : '',
        apiKey     : '',
        gpgPassword: '',
        ossUser    : '',
        ossPassword: ''
]
if (!isLocalBuild) {
    // CI build, load from environment variables
    println "# $projectName: '$localPropertiesName' not found, loading deployment config from environment variables"

    uploadConfig.user = System.env.BINTRAY_USER
    uploadConfig.apiKey = System.env.BINTRAY_API_KEY
    uploadConfig.gpgPassword = System.env.BINTRAY_GPG_PASSWORD
    uploadConfig.ossUser = System.env.BINTRAY_OSS_USER
    uploadConfig.ossPassword = System.env.BINTRAY_OSS_PASSWORD
} else {
    // Local build, load from local.properties
    println "# $projectName: '$localPropertiesName' found, loading deployment config from file"
    Properties fileProperties = new Properties()
    fileProperties.load(project.rootProject.file(localPropertiesName).newDataInputStream())

    uploadConfig.user = fileProperties.getProperty('bintray.user')
    uploadConfig.apiKey = fileProperties.getProperty('bintray.apikey')
    uploadConfig.gpgPassword = fileProperties.getProperty('bintray.gpg.password')
    uploadConfig.ossUser = fileProperties.getProperty('bintray.oss.user')
    uploadConfig.ossPassword = fileProperties.getProperty('bintray.oss.password')
}

// configure the Bintray upload plugin
bintray {
    user = uploadConfig.user
    key = uploadConfig.apiKey

    configurations = ['archives']
    pkg {
        repo = 'maven'
        name = POM_ARTIFACT_ID
        desc = POM_DESCRIPTION
        websiteUrl = POM_URL
        issueTrackerUrl = POM_ISSUE_URL
        vcsUrl = POM_SCM_URL
        licenses = ["Apache-2.0"]
        publish = true
        publicDownloadNumbers = true
        
        // noinspection GroovyAssignabilityCheck
        version {
            desc = POM_DESCRIPTION
            gpg {
                sign = true // Determines whether to GPG sign the files. The default is false
                passphrase = uploadConfig.gpgPassword // Optional. The passphrase for GPG signing
            }
            // Auto-sync to MavenCentral when uploaded to jCenter successfully
            mavenCentralSync {
                sync = true
                user = uploadConfig.ossUser
                password = uploadConfig.ossPassword
                close = '1'
            }
        }
    }
}

// configure the Maven plugin for Android and non-Android modules
if (project.getPlugins().hasPlugin('com.android.application') || project.getPlugins().hasPlugin('com.android.library')) {
    install {
        repositories.mavenInstaller {
            configuration = configurations.archives

            pom.groupId = GROUP
            pom.artifactId = POM_ARTIFACT_ID
            pom.version = VERSION_NAME

            pom.project {
                name POM_NAME
                packaging POM_PACKAGING
                description POM_DESCRIPTION
                url POM_URL

                scm {
                    url POM_SCM_URL
                    connection POM_SCM_CONNECTION
                    developerConnection POM_SCM_DEV_CONNECTION
                }

                licenses {
                    license {
                        name POM_LICENCE_NAME
                        url POM_LICENCE_URL
                        distribution POM_LICENCE_DIST
                    }
                }

                developers {
                    developer {
                        id POM_DEVELOPER_ID
                        name POM_DEVELOPER_NAME
                    }
                }
            }
        }
    }

    // Re-configure androidJavadocs as it may fail on some builds due to missing Gradle task (older versions)
    task androidJavadocs(type: Javadoc) {
        source = android.sourceSets.main.java.source
        classpath += project.files(android.getBootClasspath().join(File.pathSeparator))
        failOnError true // you can also disable this if you think docs ARE not IMPORTANT!!!!!!11one
        println "# $projectName: Configured Android javadocs"
    }
    task androidJavadocsJar(type: Jar, dependsOn: androidJavadocs) {
        classifier = 'javadoc'
        from androidJavadocs.destinationDir
    }
    task androidSourcesJar(type: Jar) {
        classifier = 'sources'
        from android.sourceSets.main.java.source
    }
} else {
    // this is config for a non-Android module
    install {
        repositories.mavenInstaller {
            pom.groupId = GROUP
            pom.artifactId = POM_ARTIFACT_ID
            pom.version = VERSION_NAME

            pom.project {
                name POM_NAME
                packaging POM_PACKAGING
                description POM_DESCRIPTION
                url POM_URL

                scm {
                    url POM_SCM_URL
                    connection POM_SCM_CONNECTION
                    developerConnection POM_SCM_DEV_CONNECTION
                }

                licenses {
                    license {
                        name POM_LICENCE_NAME
                        url POM_LICENCE_URL
                        distribution POM_LICENCE_DIST
                    }
                }

                developers {
                    developer {
                        id POM_DEVELOPER_ID
                        name POM_DEVELOPER_NAME
                        email POM_DEVELOPER_EMAIL
                    }
                }
            }
        }
    }

    // configure sources and documentation tasks (needed as default config fails on some newer Gradle versions)
    task sourcesJar(type: Jar, dependsOn: classes) {
        classifier = 'sources'
        from sourceSets.main.allSource
    }
    task javadocJar(type: Jar, dependsOn: javadoc) {
        classifier = 'javadoc'
        from javadoc.getDestinationDir()
        failOnError false
        println "# $projectName: Configured JAR javadocs"
    }
}

// another workaround...
if (JavaVersion.current().isJava8Compatible()) {
    allprojects {
        tasks.withType(Javadoc) {
            options.addStringOption('Xdoclint:none', '-quiet')
        }
    }
}

// one more output config specific for Android modules (but keeping the behavior for non-Android modules)
artifacts {
    if (project.getPlugins().hasPlugin('com.android.application') || project.getPlugins().hasPlugin('com.android.library')) {
        archives androidSourcesJar
        archives androidJavadocsJar
    } else {
        archives sourcesJar
        archives javadocJar
    }
}

projectRoot > gradle.properties

# Project-wide Gradle settings
# IDE (e.g. Android Studio) users:
# Gradle settings configured through the IDE *will override*
# any settings specified in this file.
# For more details on how to configure your build environment visit
# http://www.gradle.org/docs/current/userguide/build_environment.html
# Specifies the JVM arguments used for the daemon process.
# The setting is particularly useful for tweaking memory settings.
org.gradle.jvmargs=-Xmx1536m

# When configured, Gradle will run in incubating parallel mode.
# This option should only be used with decoupled projects. More details, visit
# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
# org.gradle.parallel=true                                        << best if left disabled for CI builds

# POM project location config
POM_URL=https://github.com/milosmns/blinking-image-view
POM_SCM_URL=https://github.com/milosmns/blinking-image-view
POM_SCM_CONNECTION=scm:git:git://github.com/milosmns/blinking-image-view.git
POM_SCM_DEV_CONNECTION=scm:git:ssh://git@github.com:milosmns/blinking-image-view.git
POM_ISSUE_URL=https://github.com/milosmns/blinking-image-view/issues

# POM licensing config
POM_LICENCE_NAME=GNU GENERAL PUBLIC LICENSE
POM_LICENCE_URL=https://www.gnu.org/licenses/gpl-3.0.en.html
POM_ALL_LICENCES=['GPL-3.0']
POM_LICENCE_DIST=repo

# POM project labeling
POM_NAME=Blinker View
POM_DESCRIPTION=A simple Android View that blinks the source image
POM_ARTIFACT_ID=blinkerview
POM_PACKAGING=aar
GROUP=me.angrybyte.blinkerview

# POM developer config
POM_DEVELOPER_ID=milosmns
POM_DEVELOPER_NAME=Milos Marinkovic
POM_DEVELOPER_EMAIL=milosmns@gmail.com

projectRoot > library > build.gradle

apply plugin: 'com.android.library'

android {
    // versions are declared in projectRoot > build.gradle
    compileSdkVersion COMPILE_SDK
    buildToolsVersion BUILD_TOOLS

    defaultConfig {
        // versions are declared in projectRoot > build.gradle
        minSdkVersion MINIMUM_SDK
        targetSdkVersion TARGET_SDK
        versionCode VERSION_CODE
        versionName VERSION_NAME
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    // this is used in the demo app only, don't worry about signing :)
    signingConfigs {
        release {
            keyAlias SIGNING_NAME
            keyPassword SIGNING_NAME
            storeFile file('../signing/keystore.jks')
            storePassword SIGNING_NAME
        }
    }
    
    // CI note: specific options for TravisCI emulators (they take a while to start)
    adbOptions {
        timeOutInMs 20 * 60 * 1000 // 20 minutes
        installOptions "-d", "-t"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }

    // if you don't support Java 8 sugar, you can just delete this block 
    // but you really should look into supporting it
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {
    // versions are declared in projectRoot > build.gradle
    implementation "com.android.support:appcompat-v7:$APPCOMPAT"
}

// a customized script that combines configuration for both Maven plugin and Bintray plugin
// it's located in `projectRoot/gradle`
apply from: '../gradle/gradle-mvn-push.gradle'

projectRoot > local.properties

# This file is automatically generated by Android Studio.
# Do not modify this file -- YOUR CHANGES WILL BE ERASED!     << not really, this config was kept for years in my case
#
# This file must *NOT* be checked into Version Control Systems,
# as it contains information specific to your local configuration.
#
# Location of the SDK. This is only used by Gradle.
# For customization when using a Version Control System, please read the
# header note.
# Sun Apr 09 16:34:43 CEST 2016
sdk.dir=/wherever/your/sdk/is/located/

# jCenter config
bintray.user=username_placeholder
bintray.apikey=apikey_placeholder
bintray.gpg.password=password_placeholder
# MavenCentral config
bintray.oss.user=username_placeholder
bintray.oss.password=password_placeholder