In the serie “create a real time line graph on Android”, MPAndroidChart seems to be the best solution. Library is designed for Android 5 Lollipop and rendering is great. MPAndroidChart is open source an available here on Github : https://github.com/PhilJay/MPAndroidChart . Developer is very active and answers quickly to issues created by users.
The following video shows how to create a real time line graph on Android with MPAndroidChart steps by steps :
As you can see in the video, result is great and tutorials with graph will continue in following weeks with MPAndroidChart has library used. Stay in touch !