Android "font asset not found" error

I am developing for Android version 22.

I am getting the runtime exception "Font asset not found"

Here is the code:

Typeface customFont =    Typeface.createFromAsset(getAssets(), "fonts/norwester.otf");

And here is my file structure:

I am guessing that my file structure is wrong because the "assets" folder does not show up in "Android" mode and only shows up in "Project Mode".

What is the problem?