You mean creating a framework or using the framework ? Creating a project you like is always a good way to learn a programming language. However, using a framework before knowing a programming language is not a good way imo, because you will actually learn the framework, and not the language really. You need at least to know the basic notions and concepts of c++ before using the framework. I hope this answers your question :)

Using the framework... I find the only way to learn a language is to build something with it .

Unity does a lot of hand holding in this regard