This is a step by step guide to set up the automated build process using Jenkins CI for your Android projects. The following steps assume that you have new hardware with just any flavor of Linux installed. It is also taken into account that you might have a remote machine.

PART I: Initial setup on your machine

1. Log in via ssh to your Ubuntu machine:

   ssh [email protected]

2. Download a version of the Android SDK on your machine:

   wget https://dl.google.com/android/android-sdk_r24.4.1-linux.tgz

3. Unzip the downloaded tar file:

   sudo apt-get install tar
   tar -xvf android-sdk_r24.4.1-linux.tgz

4. Now you need to install Java 8 on your Ubuntu machine, which is a requirement for Android builds on Nougat. Jenkins would require you to install JDK and JRE 7 using the steps below:

   sudo apt-get install python-software-properties
   sudo add-apt-repository ppa:webupd8team/java
   sudo apt-get update
   apt-get install openjdk-8-jdk

5. Now install Jenkins on your Ubuntu machine:

   wget -q -O - https://pkg.jenkins.io/debian/jenkins-ci.org.key | sudo apt-key add -
   sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'
   sudo apt-get update
   sudo apt-get install jenkins

6. Download the latest supported Gradle version for your Android setup:

   wget https://services.gradle.org/distributions/gradle-2.14.1-all.zip
   unzip gradle-2.14.1-all.zip

7. Set up Android on your Ubuntu machine. First move to the tools folder in the Android SDK folder downloaded in step 2:

   cd android-sdk-linux/tools // lists available SDK
   android update sdk --no-ui // Updates SDK version
   android list sdk -a | grep "SDK Build-tools" // lists available build tools
   android update sdk -a -u -t 4 // updates build tools version to one listed as 4 by prev. cmd.
   update java

8. Install Git or any other VCS on your machine:

   sudo apt-get install git

9. Now log in to Jenkins using your internet browser. Type ipAddress:8080 into the address bar.

10. In order to receive the password for the first-time login, please check the corresponding file as follows (you will need su permissions to access this file):

    cat /var/lib/jenkins/secrets/initialAdminPassword

PART II: Set up Jenkins to build Android Jobs

1. Once logged in, go to the following path:

   Jenkins > Manage Jenkins > Global Tool Configuration

2. At this location, add JAVA_HOME with the following entries:

   Name = JAVA_HOME
   JAVA_HOME = /usr/lib/jvm/java-8-openjdk-amd64

3. Also add the following values to Git and save the environment variables:

   Name = Default
   /usr/bin/git

4. Now go to the following path:

   Jenkins > Manage Jenkins > Configuration

5. At this location, add ANDROID_HOME to the "global properties":

   Name = ANDROID_HOME
   Value = /home/username/android-sdk-linux

Part III: Create a Jenkins Job for your Android project

1. Click on New Item in the Jenkins home screen.

2. Add a Project Name and Description.

3. In the General tab, select Advanced. Then select Use custom workspace:

   Directory /home/user/Code/ProjectFolder

4. In the source code management select Git. I am using Bitbucket for the purpose of this example:

   Repository URL = https://username:[email protected]/project/projectname.git

5. Select additional behaviors for your repository:

   Clean Before Checkout
   Checkout to a sub-directory. Local subdirectory for repo /home/user/Code/ProjectFolder

6. Select a branch you want to build:

   */master

7. In the Build tab, select Execute Shell in Add build step.

8. In the Execute shell, add the following command:

   cd /home/user/Code/ProjectFolder && gradle clean assemble --no-daemon

9. If you want to run Lint on the project, then add another build step into the Execute shell:

   /home/user/gradle/gradle-2.14.1/bin/gradle lint

Now your system is finally set up to build Android projects using Jenkins. This setup makes your life so much easier for releasing builds to QA and UAT teams.

PS: Since Jenkins is a different user on your Ubuntu machine, you should give it rights to create folders in your workspace by executing the following command:

chown -R jenkins .git