Development Environment

The core team uses Debian GNU/Linux + Android Studio, latest version. It is also available for Windows and Mac, but we never used that. You can use any Android device connected to USB to run your code straight from Android Studio on the device. Be aware that you cannot install your own built version and F-Droid’s at the same time. You can export and import your database, though.

Tools

You need to install

• a Java Development Kit (JDK)
• git
• adb (Android Debug Bridge, included in Android Studio)

On Ubuntu, you can use following commands (java 9 seems broken, please use java 8)

sudo apt-get install java-1.8.0-openjdk-amd64 git adb

Getting the code

git clone https://codeberg.org/Freeyourgadget/Gadgetbridge.git

(after you did that once, you can use git pull to get the newest Gadgetbridge code)

Alternatively you can use Android Studio to clone the Gadgetbridge repository.

Building and installing the Gadgetbridge apk

If you only want to compile the code, you can simply execute

./gradlew assembleDebug

or

./gradlew assembleRelease

And install it to your mobile or tablet by executing

adb install app/build/outputs/apk/app-debug.apk

Android Studio does all this automatically when you press the Run or Debug button.

Short Introduction to Gadgetbridge’s Source Code

Important Classes

• PebbleSupport (see class hierarchy)
• PebbleProtocol (pebble communication protocol)
• PebbleIOThread (background thread for pebble communication)
• MiBandSupport (see class hierarchy)
• BtLEQueue (communication queue for Bluetooth LE devices)
• DeviceCommunicationService (Android service channeling the communication with devices)
• DeviceService (“client side API” of DeviceCommunicationService, see GBApplication#deviceService())
• GBDevice (generic, device-unspecific)
• DeviceCoordinator (see class hierarchy)
• ControlCenter (main activity)

Overview

All the details about the communication/protocol with a concrete device (Pebble, Mi Band, ...) is inside the “Concrete Device Impl.” component, that is, the concrete implementations of the DeviceSupport interface. Only the DeviceCommunicationService has access to those -- clients (typically Activities) talk to the DeviceService interface in order to communicate with the devices.

Bluetooth Error Codes

https://android.googlesource.com/platform/external/bluetooth/bluedroid/+/android-5.1.1_r37/stack/include/gatt_api.h

Logging

We use slf4j for logging, so just use LoggerFactory.getLogger(Your.class) and log away. The output will be written to the Android Log (so you can get it with logcat or Android Studio) as well as to the file /sdcard/Android/data/nodomain.freeyourgadget.gadgetbridge/files/gadgetbridge.log. File logging needs to be enabled in Gadgetbridge’s preferences, first.

Information Display

Use one of the nodomain.freeyourgadget.gadgetbridge.util.GB#toast() methods to display information to the user. They

• not only display, but also log warnings and errors
• can safely be called from a background thread

Database

We use greenDAO for database access. See nodomain.freeyourgadget.gadgetbridge.daogen.GBDaoGenerator for entity definition and generation.