Install Android SDK on Ubuntu

sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386 lib32z1 libbz2-1.0:i386
sudo gedit /etc/profile

add :

#AndroidDev PATH
export PATH=${PATH}:/opt/android-sdk-linux/tools
export PATH=${PATH}:/opt/android-sdk-linux/platform-tools

at the end run the following command to refresh profile or restart your system

. /etc/profile

Or
add this to ~/.bashrc :

export ANDROID_HOME=/<installation location>/android-sdk-linux
export PATH=${PATH}:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

References
https://help.ubuntu.com/community/AndroidSDK
https://developer.android.com/studio/install.html