Decompile an app

Install APK Extractor

Download link : APK Extractor

Run APK Extractor

Use it to extract the .apk of your file
Download the APP_NAME.apk on your computer

Download dex2jar


Download link

Use dex2jar

path/to/dex-tools-2.1/d2j-dex2jar.sh APP_NAME.apk

APP_NAME-dex2jar.jar will be created

Download jd-gui


Download link

Use jd-gui

java -jar jd-gui-1.6.6.jar APP_NAME-dex2jar.jar

Manually install SDK

Choose version

10406996 = 11.0
9862592  = 10.0
9477386  = 9.0
9123335  = 8.0
8512546  = 7.0
export ANDROID_SDK_ROOT=$HOME/.android/sdk
curl https://dl.google.com/android/repository/commandlinetools-linux-9477386_latest.zip -o file.zip
mkdir -p $ANDROID_SDK_ROOT/cmdline-tools/
unzip file.zip -d $ANDROID_SDK_ROOT/
mv $ANDROID_SDK_ROOT/cmdline-tools/ $ANDROID_SDK_ROOT/temp
mkdir -p $ANDROID_SDK_ROOT/cmdline-tools/latest
mv $ANDROID_SDK_ROOT/temp/* $ANDROID_SDK_ROOT/cmdline-tools/latest
touch $ANDROID_SDK_ROOT/repositories.cfg

# accept licenses
yes | $SDKMANAGER --licenses

$SDKMANAGER tools platform-tools
# installe correct version
$SDKMANAGER 'platforms;android-10'
$SDKMANAGER 'build-tools;28.0.3'
$SDKMANAGER "system-images;android-29;default;x86"

$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/avdmanager create avd -n TestAVD -k "system-images;android-29;default;x86" --device "pixel_4"
# $AVD_MANAGER delete avd -n TestAVD

$ANDROID_SDK_ROOT/emulator/emulator -list-avds
# show TestAVD

$ANDROID_SDK_ROOT/emulator/emulator -avd TestAVD