The way how I do this is by having written a code-generator that takes a simple YAML like file with a data model description and generates SQL models/NOSQL models for backend storage, POJO access code to that and POJO access for a rest API; then an angular backend that accesses the api and locally stores it and directives to display it; then an android sqlite local database wrapped in a content provider to access it, async task helpers to retrieve the content via sync providers and adapters to display them. I haven't yet started with iOS.

Any wellfunctioning code that I have written I pack into my content generator and give access to via the YAML. The whole thing has gotten really ugly and desperately needs refactoring (it's in Perl and I am rewriting it in Stringtemplate) but it does help me with:

- the changes in the model that cascade down the frontends

- fixing a bug in one application that needs fixing in several others

- the fact that multi-platform model really is stressful since the brain needs to switch rapidly between different languages and platform APIs and this allows me to write code once and perpetuate data model changes on to all platforms.

So I think, take code of yours that works and wrap a codegenerator around it. It's better than using a framework where you don't know what's underneath. All the code is something you know and built.