Intro to MVP, RxJava and Dagger

Transcript

1. MVP, Dagger and RxJava By Himanshu Bansal
2. M.V.P is our MVP
3. Problems • Android does not encourage developers to write clean code • Many Android components viz Activity, Fragment, Broadcast Receiver, Service, AsyncTask etc. Writing your own domain components on top of these, code starts to look like a ‘spaghetti’ • It’s extremely difficult to maintain a good software design, even before scale. • Code contains dependencies concealed inside big classes, no way to test and debugging takes more time • Gradually, the code becomes less D.R.Y, more open for modification, gets loaded with generic interfaces which you dare to modify • It’s like playing a game of Go and slowly exhausting all your options
5. Model View Presenter • Derived from the old MVC pattern • Helps reinforce S.O.L.I.D, K.I.S.S and D.R.Y • Writing test cases is a breeze • Handle config changes easily from one place, by caching presenters independently of View classes
6. Science Diagrams
9. Dagger 2
10. Dagger 2 • Better than Dagger 1, does not rely on runtime graph compositions and reflection • Dependency Injection Framework using Annotation Processors • Helps implement ‘D’ part of S.O.L.I.D principle • Separate class system which manages all the dependencies inside code using Modules/Components/SubComponents • Then for unit testing, these modules can be swapped with mock modules • Simplifies access to shared instances • Custom Scoped Instances • Multibinding
11. RxJava
12. RxAndroid • Reactive extensions written in Java, inspired from .NET • Simplifies the ability to chain async operations (using Schedulers) • Eliminates the need for unnecessary state variables, which can add bugs • Android can be more efficiently described as a system which operates on streams of data which are asynchronously emitted from various sources (Observables) • From touch events, broadcasts, service and network callbacks etc. All these events can be easily modeled using reactive extensions which work best with the Observer pattern • Ton of operators • Backpressure
14. Everything adds up +++
15. Further reading Mosby Viper Clean Code MVC vs MVP vs MVVM RxJava Samples Codepath Guides Google Sample - MVP Callback Hell Reactive Programming Reactive Extensions RxJava Official Wiki Activities are not UI elements Why MVP in Android ? Marvel app MVP Dribble Client MVP
16. Medium goodness ! • Yet another MVP article • Understanding Dagger 2 • Dagger 2 • Dagger 2 + Rx + MVP • Android MVP Architecture and Dependency Injection • Dagger Multibinding • Activities SubComponent Multibinding
17. @Ask {Questions}
18. @Inject {Thanks}