Android NDK Eclipse Ubuntu 18.04 Installation Guide
Hi! This tutorial will guide you step-by-step on How to Install Android NDK Eclipse Ubuntu 18.04 Bionic LTS GNU/Linux.
First, the Android NDK is a Toolset that allows you to Implement parts of your App using Native-Code Languages such as C and C++.
Moreover, on the Android NDK Eclipse Ubuntu Tutorial Bottom Link to Getting-Started with Hello-World Android NDK Development on Eclipse.
Especially relevant: first you have to Install Android NDK and after Make the NDK Eclipse Integration Set-up.
Finally, the Contents and Details are Expressly Minimal to Give Focus Only to the Essentials Instructions and Commands ;)

How to Install Android NDK on Ubuntu Linux
Then to Set-up Eclipse Android NDK Plugin source
Add the Software Source:
Like:
https://dl-ssl.google.com/android/eclipse/
After to Install the Eclipse Android NDK Plugin
Select the NDK Plugins Checkbox and Follow..Again Select Eclipse > Window > Prefereces.
And finally Set Up Android NDK Path
Set or Browse for the NDK Installation Location:Getting-Started with Android NDK Code Development