Question: I use php-sessions to check if users are logged in to my app. Is it significantly better for performance than just keeping the user id in a session and checking against the database if the user is logged in instead?

If the password changes or I want to block/log out a user it is easy to just change the database record, but when it lives in a session, can I do that? How?

Answer: 
Updating to latest Android Studio and re-importing the project fixed my issue.
To fix this issue I had to update all class names on **layout** files.

From:

```
<android.support.design.widget.CoordinatorLayout
<android.support.v7.widget.RecyclerView
...

```

to:

```
<androidx.core.widget.NestedScrollView
<androidx.coordinatorlayout.widget.CoordinatorLayout
...

```

After that, the data binding errors where gone.

I ran the migration tool, but it didn't fixed the class names on layout xmls, sad!