Building the APK

Please note when building AndroidAPS 2.0 apk: Configuration on demand is not supported by the current version of the Android Gradle plugin! If your build fails with an error regarding “on demand configuration” you can do the following:

  • Open the Preferences window by clicking File > Settings (on Mac, Android Studio > Preferences).
  • In the left pane, click Build, Execution, Deployment > Compiler.
  • Uncheck the Configure on demand checkbox.
  • Click Apply or OK.

This article is divided into two parts.

  • In the overview part there is an explanation on what steps are necessary to build the APK file.
  • In the step by step walkthrough part you will find the screenshots of a concrete installation. Because the versions of Android Studio - the software development environment which we will use to build the APK - will change very quickly this will be not identical to your installation but it should give you a good starting point. Android Studio also runs on Windows, Mac OS X and Linux and there might be small differences in some aspects between each platform. If you find that something important is wrong or missing, please inform the facebook group “AndroidAPS users” or in the Gitter chats Android APS or AndroidAPSwiki so that we can have a look at this.


In general, the steps necessary to build the APK file:

  • Install git
  • Install and setup Android Studio.
  • Use git to clone the source code from the central Github repository where the developers have put the actual code for the app.
  • Open the cloned project in Android Studio as active project.
  • Build the signed APK.
  • Transfer the signed APK to your smartphone.

Step by step walkthrough

Detailed description of the steps necessary to build the APK file.

Install Android Studio

  • Install git
    • Windows
    • Mac OS X
    • Linux - just install a package git via package manager of your distribution
  • Install Android Studio.
  • Setup Android Studio during first start

Select “Do not import settings” as you have not used it before.

Screenshot 1

Click “Next”.

Screenshot 2

Select “Standard” installation and click “Next”.

Screenshot 3

Select “Intellij” as UI (user interface) theme and click “Next”.

Screenshot 4

Click “Next” on the “Verify Settings” dialog.

Screenshot 5

The Android emulator (to emulate the smartphone on your PC or Mac) is not used to build the APK. You can click “Finish” to finish the installation and read the documentation later on demand.

Screenshot 6

Android Studio is downloading a lot of software components it uses. You can click on the “Show Details” button to the what happens but that’s not important at all.

Screenshot 7

Screenshot 8

After the downloads are completed click the “Finish” button.

Screenshot 9

  • Applause, applause you have now finished the Android Studio installation and can start cloning the source code. Maybe it’s time for a short break?

Generate signed APK

  • Use git clone in Android Studio as shown in screenshots below. Select “Check out project from Version Control” with “Git” as concrete version control system.

Screenshot 10 Version_Control_Git

Fill in the URL to the main AndroidAPS repository (“”) and click “clone”.

Screenshot 13

Android Studio will start cloning. Don’t click “Background” as it goes fast and makes things more complicated at the moment.

Screenshot 14

Finish the checkout from version control with opening the project by clicking “Yes”.

Screenshot 15

Use the standard “default gradle wrapper” and click “OK”.

Screenshot 16

Read and close the “Tip of Day” screen of Android Studio by pressing “Close”.

Screenshot 17

  • Excellent, you have your own copy of the source code and are ready to start the build.
  • Now we are approaching our first error message. Fortunately, Android Studio will directly give us the solution for this.

Click “Install missing platform(s) and sync project” as Android Studio needs to install a missing platform.

Screenshot 18

Accept the license agreement by selecting “Accept” and clicking “Next”.

Screenshot 19

As it is said in the dialog please wait until the download is finished.

Screenshot 20

Now it’s finished. Please click “Finish”.

Screenshot 21

Aaaahhh, next error. But Android Studio suggests a similar solution. Click “Install Build Tools and sync project” as Android Studio needs to download missing Tools.

Screenshot 22

As it is said in the dialog please wait until the download is finished.

Screenshot 23

Now it’s finished. Please click “Finish”.

Screenshot 24

And another error to handle as Android Studio needs to download again a missing platform. Click “Install missing platform(s) and sync project”.

Screenshot 25

As it is said in the dialog please wait until the download is finished.

Screenshot 26

Now it’s finished. Please click “Finish”.

Screenshot 27

Click “Install Build Tools and sync project” as Android Studio needs to download missing Tools.

Screenshot 28

As it is said in the dialog please wait until the download is finished.

Screenshot 29

Now it’s finished. Please click “Finish”.

Screenshot 30

Yeah, the error messages are gone and the first gradle build is runing. Maybe it’s time to drink some water?

Screenshot 31

Android Studio recommends we now update the gradle system to version 4.4. If you made this build for an AndroidAPS version before the release of at least a release candidate(RC) of version 2.0 do not follow this recommendation. Otherwise, the build will fail. The gradle system is a tool which Android Studio uses to control the build process. For AndroidAPS there is no disadvantage to using the old gradle version. The APK file in the end is not different. If you build a APK for version 2 of AndroidAPS feel free to upgrade the gradle system to version 4.4. Please click “Remind me tomorrow”.

Screenshot 32

The build is running again.

Screenshot 33

Yeah, the first build is successful but we are not finished.

Screenshot 34

Select in the menu “Build” and then “Generate Signed APK...”. Signing means that you sign your generated app but in a digital way as a kind of digital fingerprint in the app itself. That is necessary because Android has a rule that it only accepts signed code to run for security reasons. For more information on this topic, follow the link here Security is a deep and complex topic and you don’t need this now.

Screenshot 39

Select “app” and click “Next”.

Screenshot 40

Click “Create new...” to start creating your keystore. A keystore in this case is nothing more than a file in which the information for signing is stored. It is encrypted and the information is secured with passwords. We suggest storing it in your home folder and remember the passwords but if you lose this information it’s not a big issue because then you just have to create a new one. Best practice is to store this information carefully.

Screenshot 41

  • Fill in the information for the next dialog.
    • Key store path: is the path to the keystore file
    • The password fields below are for the keystore to double check for typing errors.
    • Alias is a name for the key you need. You can leave the default or give it a fancy name you want.
    • The password fields below the key are for the key itself. As always to double check for typing errors.
    • You can let the validity at the default of 25 years.
    • You only have to fill out firstname and lastname but feel free to complete the rest of information. Then click “OK”.

Screenshot 42

Fill in the information of the last dialog in this dialog and click “Next”.

Screenshot 43

Select “full” as flavour for the generated app. Select V1 “Jar Signature” (V2 is optional) and click “Finish”. The following information might be important for later use.

  • ‘Release’ should be your default choice for “Build Type”, ‘Debug’ is just for people coding.
  • Select the build type you want to build.
    • full (i.e. recommendations automatically enacted in closed looping)
    • openloop (i.e. recommendations given to user to manually enact)
    • pumpcontrol (i.e. remote control for pump, no looping)
    • nsclient (i.e. looping data of another user is displayed and careportal entries can be added)

Screenshot 44

In the event log you see that the Signed APK was generated successfully.

Screenshot 45

Click the “locate” link in the event log.

Screenshot 46

Transfer APK to smartphone

A file manager window opens. It might look a bit different on your system as I am using Linux. On Windows there will be the File Explorer and on Mac OS X the Finder. There you should see the directory with the generated APK file. Unfortunately this is the wrong place as “wear-release.apk” is not the signed “app” APK we are searching for.

Screenshot 47

Please change to the directory AndroidAPS/app/full/release to find the “app-full-release.apk” file. Transfer this file to your Android smartphone. You can do it on your preferred way, i.e. Bluetooth, cloud upload or email. I use Gmail here in this example as it is fairly simple for me. I mention this because to install the self-signed app we need to allow Android on our smartphone to do this installation even if this file is received via Gmail which is normally forbidden. If you use something other please proceed accordingly.

Screenshot 48

In the settings of your smartphone there is an area “unknown apps install” where I have to give Gmail the right to install APK files which I get via Gmail.

Screenshot 49

Select “Allow from this source”. After the installation, you can disable it again.

Screenshot 50

The last step is to press on the APK file I got via Gmail and install the app. If the APK does not install and you have an older version of AndroidAPS on your phone that was signed with a different key then you will need to uninstall this first, remember to export your settings if so!

Yeah, you got it and can now start with configuring AndroidAPS for your use (CGMS, insulin pump) etc.