1. Unmask and install the Android SDK update manager:

emerge dev-util/android-sdk-update-manager

In case you run into issues during compilation of any java ebuilds, try using the oracle-jdk-bin (1.7) !
For some reason on my machine some ebuilds failed using the icedtea-bin.

2. Add all users who should be allowed using it to the 'android' group:

gpasswd -a <user> android

3. In case you added yourself relog now, then run:

export ANDROID_SWT=/usr/share/swt-3.7/lib

and install at least the platform-tools package.

ADB will be at /opt/android-sdk-update-manager/platform-tools/adb

5. Finally edit your .bashrc file to add adb to your PATH:

 export PATH="/opt/android-sdk-update-manager/platform-tools/:${PATH}" 


Add the following udev rules to e.g. /etc/udev/rules.d/80-android.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="22b8", MODE="0666", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0bb4", MODE="0666", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="04e8", MODE="0666", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="18d1", MODE="0666", GROUP="plugdev"
Restart udevd and make sure you are member of the plugdev group.

Plugin your Android device via usb

Test the connection

adb devices

That should give you a list of connected Android devices

Now what ?