New Sample: Model View Intent

New sample proposal

I’d like to create a new sample to illustrate the Model View Intent pattern. Full Android examples for MVI are hard to find. It’s a pattern that has seen wide adoption in the Javascript and .NET world. Target audience include, but not limited to:

• Developers making the pivot from an imperative to declarative style of programming.
• Developers looking for best-practices in functional or reactive programming on Android.

Here are some articles/examples explaining the core principles of MVI and unidirectional flow:

• http://hannesdorfmann.com/android/model-view-intent
• https://cycle.js.org/model-view-intent.html
• http://thenewstack.io/developers-need-know-mvi-model-view-intent/

Proposed stack

I’m hoping to use specific libraries to achieve this in the cleanest possible way. A requirement with the android-architecture samples is to use accepted industry standard. A few of these libraries are new as of this year, but I believe they still fulfill that requirement. I’ve taken the time to establish a small ‘pedigree’ for each.

The following are battle-tested libraries. Battle tested here means that they have documented use, in production, at major companies with a large user base. Places such as Square, Groupon, Trello, Shopify, etc. One notable exception is RxJava2. RxJava 2 has major community backing, and will see a production release later this month.

Also, the following all have well-know, senior maintainers with established track records. Below a detailed list with rationale/credentials:

• RxJava 2
  • Great talk by Jake Wharton outlining usage & benefits
  • Observable and Flowable clears up the muddled semantics around Backpressure in RxJava 1.
  • Better type safety.
  • Improved Subscriber model.
  • Currently RC4, General availability planned for 29/10/2016
  • Contributors include Jake Wharton and David Karnok
  • IMO deprecates RxJava 1.
• Retrofit
  • Battle tested, used in other samples.
  • RxJava 2 adapter currently available, built by JakeWharton.
• Toothpick
  • Lightweight DI library.
  • Full-featured, runtime based, but reflection free, implementation of JSR 330.
  • Performant and much less code overhead / complexity than Dagger 2.
  • Great presentation outlining usage & benefits.
  • Audio for the talk
  • Primary maintainer is Stephane Nicolas, senior engineer at Groupon.
• Retrolambda
  • Lambdas are necessary for readable functional / reactive code.
  • Retrolambda routinely used in production for big projects (Square, Trello, etc.)

[kanawish]

To be honest, I’ve only starting working on this last week. Since I wrote this proposal, I spoke at 3 conferences, and spent a week in Mountain View for the GDE summit + Workshops.

I’m hoping to get an initial PR up sometime next week-end. I might appreciate earlier feedback, I’ll reach out on Slack once my base pattern is close to something I feel happy with.

[JoseAlcerreca]

https://github.com/oldergod/android-architecture added to external samples!