The Kivy GUI is used with Electrum on Android devices. To generate an APK file, follow these instructions.
✓ These binaries should be reproducible, meaning you should be able to generate binaries that match the official releases.
This assumes an Ubuntu (x86_64) host, but it should not be too hard to adapt to another similar system.
-
Install Docker
See
contrib/docker_notes.md
. -
Build binaries
The build script takes a few arguments. To see syntax, run it without providing any:
$ ./build.sh
For development, consider e.g.
$ ./build.sh kivy arm64-v8a debug
If you want reproducibility, try instead e.g.:
$ ELECBUILD_COMMIT=HEAD ELECBUILD_NOCACHE=1 ./build.sh kivy all release-unsigned
-
The generated binary is in
./dist
.
Every user can verify that the official binary was created from the source code in this repository.
- Build your own binary as described above.
Make sure you don't build in
debug
mode, instead use either ofrelease
orrelease-unsigned
. If you build inrelease
mode, the apk will be signed, which requires a keystore that you need to create manually (see source ofmake_apk.sh
for an example). - Note that the binaries are not going to be byte-for-byte identical, as the official
release is signed by a keystore that only the project maintainers have.
You can use the
apkdiff.py
python script (written by the Signal developers) to compare the two binaries.This should output$ python3 contrib/android/apkdiff.py Electrum_apk_that_you_built.apk Electrum_apk_official_release.apk
APKs match!
.
You probably need to clear the cache: rm -rf .buildozer/android/platform/build-*/{build,dists}
Assuming adb
is installed:
$ adb -d install -r dist/Electrum-GLC-*-arm64-v8a-debug.apk
$ adb shell monkey -p org.electrum_glc.electrum_glc 1
$ sudo docker run -it --rm \
-v $PWD:/home/user/wspace/electrum \
-v $PWD/.buildozer/.gradle:/home/user/.gradle \
--workdir /home/user/wspace/electrum \
electrum-android-builder-img
See log_level
in buildozer.spec
This should work OK for most scenarios:
adb logcat | grep python
Better grep
but fragile because of cut
:
adb logcat | grep -F "`adb shell ps | grep org.electrum_glc.electrum_glc | cut -c14-19`"
Install Kivy.
Build atlas: (cd contrib/android/; make theming)
Run electrum with the -g
switch: electrum-glc -g kivy
If you just follow the instructions above, you will build the apk
in debug mode. The most notable difference is that the apk will be
signed using a debug keystore. If you are planning to upload
what you build to e.g. the Play Store, you should create your own
keystore, back it up safely, and run ./contrib/make_apk.sh release
.
See e.g. kivy wiki and android dev docs.
Note that this only works for debug builds! Otherwise the security model of Android does not let you access the internal storage of an app without root. (See this)
$ adb shell
$ run-as org.electrum_glc.electrum_glc ls /data/data/org.electrum_glc.electrum_glc/files/data
$ run-as org.electrum_glc.electrum_glc cp /data/data/org.electrum_glc.electrum_glc/files/data/wallets/my_wallet /sdcard/some_path/my_wallet
Or use Android Studio: "Device File Explorer", which can download/upload data directly from device (via adb).
cd dist/
unzip Electrum-*.apk1 -d apk1
mkdir apk1/assets/private_mp3/
tar -xzvf apk1/assets/private.mp3 --directory apk1/assets/private_mp3/
unzip Electrum-*.apk2 -d apk2
mkdir apk2/assets/private_mp3/
tar -xzvf apk2/assets/private.mp3 --directory apk2/assets/private_mp3/
sudo chown --recursive "$(id -u -n)" apk1/ apk2/
chmod -R +Xr apk1/ apk2/
$(cd apk1; find -type f -exec sha256sum '{}' \; > ./../sha256sum1)
$(cd apk2; find -type f -exec sha256sum '{}' \; > ./../sha256sum2)
diff sha256sum1 sha256sum2 > d
cat d
The CI (Cirrus) builds apks on most git commits.
See e.g. here.
The task name should start with "Android build".
Click "View more details on Cirrus CI" to get to cirrus' website, and search for "Artifacts".
The apk is built in debug
mode, and is signed using an ephemeral RSA key.
For tech demo purposes, you can directly install this apk on your phone. However, if you already have electrum installed on your phone, Android's TOFU signing model will not let you upgrade that to the CI apk due to mismatching signing keys. As the CI key is ephemeral, it is not even possible to upgrade from an older CI apk to a newer CI apk.
However, it is possible to resign the apk manually with one's own key, using
e.g. apksigner
,
mutating the apk in place, after which it should be possible to upgrade:
apksigner sign --ks ~/wspace/electrum/contrib/android/android_debug.keystore Electrum-*-arm64-v8a-debug.apk