When running this example in the emulator the application crashes during startup with the following exception (using a device with API 26):

[...]
Caused by: java.lang.IllegalArgumentException: You need to use a Theme.AppCompat theme (or descendant) with the design library.
                                                     at android.support.design.widget.ThemeUtils.checkAppCompatTheme(ThemeUtils.java:33)
                                                     at android.support.design.widget.TabLayout.<init>(TabLayout.java:298)
[...]

To fix it, I had to change the theme in res/values/base-template-styles.xml from android:Theme.Material.Light to Theme.AppCompat.Light.

My Android Studio's version is 3.0.1 and if I just integrate from Github your project to Android Studio I have following errors that I would not like to see:

in android.support.design.widget.TabLayout attributes app:tabMode and tabGravity were not found. I commented them out and now there is an error package android.support.design.widget does not exist
etc.

and I'm sure if I solve this next problem arises and so on. From this description you see that I'm a newcomer in these technologies but I would like to get a working example first and then deepen my understanding of these technologies.

I just wanted to try how android notifications work on lock screen from implementation point of view but now I'm frustrated. What can I do; is there in Android Studio a magic button resolving all version conflicts etc. to get this work ? I would not like to study this long ...

Or is there some other github project demonstrating these things that works better.

gradle shows

No resource identifier found for attribute tabMode and tabGravity

need to add Design lib manually.