CustomBehavior | An example of a custom CoordinatorLayout Behvior

Well, for starters, the first error you are getting is an error on std::array in Derived::SetCustomBehavior():

error: wrong number of template arguments (1, should be 2)

You also have an error on std::ref(std::placeholders::_1), it should be just std::placeholders::_1.

Fixing those two mistakes, the code then compiles and runs (using corrected asserts):

Online Demo

That being said, you don't actually need std::bind() at all in this situation. Your custom_f parameter is the same type as your customCallback member, so simply assign custom_f as-is to customCallback.

And do yourself a favor - create type aliases for your std::function and std::array types to make your code more readable.

Try this:

base.h