lupsyn / music-mvp-rx

A showcase of RxJava and Model View Presenter, plus a number of other popular libraries for android development, including Dagger2, Retrofit, and ButterKnife.

Music-mvp-rx

A showcase of RxJava and Model View Presenter, plus a number of other popular libraries for android development, including Dagger2, Retrofit, and ButterKnife. Unit tests covering any business logic and Robolectric tests verifying the ui.

The app is a simple master/detail implementation: we retrieve a list of elements from the Shazam api and present them on the MusicFragment in a RecyclerView. When an element is clicked on, we load it in by itself in the MusicDetailFragment.

Benefits

This setup has a number of advantages over a non-MVP app architecture

• it separates our concerns
  • the Presenter is view agnostic and does not care how an action was triggered, making a clear division which is easy to change
  • the view which implements the View interface is very simple - the methods are usually one liners, doing something on the android Activity e.g. just setting a view's state to View.GONE - which also makes them easy to test
• it allows us to place all our business logic within the Presenter object and abstracts the View for easy mocking, so we can unit test all the things, e.g:
  • when we're doing a network request, does the loading indicator show when it starts, and hide when it ends?
  • are we ignoring clicks on the 'refresh' button when a network call doing a refresh is already in progress?
  • what happens when a network call fails?
  • ... etc
• support for orientation changes (e.g. device rotation) with very little effort
• the power of rxjava
  • Observables exposing future actions via the View interface, allowing our Presenters to be entirely stateless
  • easy to do long running operations off the main thread
  • in app code but also in the unit tests, e.g the excellent TestScheduler

Implementation

This project has a separate module called mocks. Our android application module app has a testCompile dependency on the mocks module. (Injected with dagger) We have created a LocalResponseDispatcher which takes care of the local API needs, we use MockWebserver to test the API calls.

Also the testCompile in the core module depends on mocks in which we have stored .json response, in order to correctly test in Junit plain tests.

License

MIT License

Copyright (c) 2017 Enrico Bruno Del Zotto

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.