google 官方android mvp demo

# TODO-MVP ### Summary This sample is the base for many of the variants. It showcases a simple implementation of the Model-View-Presenter pattern with no architectural frameworks. It uses manual dependency injection to provide a repository with local and remote data sources. Asynchronous tasks are handled with callbacks. <img src="https://github.com/googlesamples/android-architecture/wiki/images/mvp.png" alt="Diagram"/> Note: in a MVP context, the term "view" is overloaded: * The class android.view.View will be referred to as "Android View" * The view that receives commands from a presenter in MVP, will be simply called "view". ### Fragments It uses fragments for two reasons: * The separation between Activity and Fragment fits nicely with this implementation of MVP: the Activity is the overall controller that creates and connects views and presenters. * Tablet layout or screens with multiple views take advantage of the Fragments framework. ### Key concepts There are four features in the app: * <code>Tasks</code> * <code>TaskDetail</code> * <code>AddEditTask</code> * <code>Statistics</code> Each feature has: * A contract defining the view and the presenter * An Activity which is responsible for the creation of fragments and presenters * A Fragment which implements the view interface. * A presenter which implements the presenter interface In general, the business logic lives in the presenter and relies on the view to do the Android UI work. The view contains almost no logic: it converts the presenter's commands to UI actions and listens to user actions, which are passed to the presenter. Contracts are interfaces used to define the connection between views and presenters. ### Dependencies * Common Android support libraries (<code>com.android.support.\*)</code> * Android Testing Support Library (Espresso, AndroidJUnitRunner…) * Mockito * Guava (null checking) ## Features ### Complexity - understandability #### Use of architectural frameworks/libraries/tools: None #### Conceptual complexity Low, as it's a pure MVP implementation for Android ### Testability #### Unit testing High, presenters are unit tested as well as repositories and data sources. #### UI testing High, injection of fake modules allow for testing with fake data ### Code metrics Compared to a traditional project with no architecture in place, this sample introduces additional classes and interfaces: presenters, a repository, contracts, etc. So lines of code and number of classes are higher in MVP. ``` ------------------------------------------------------------------------------- Language files blank comment code ------------------------------------------------------------------------------- Java 46 1075 1451 3451 XML 34 97 337 601 ------------------------------------------------------------------------------- SUM: 80 1172 1788 4052 ------------------------------------------------------------------------------- ``` ### Maintainability #### Ease of amending or adding a feature High. #### Learning cost Low. Features are easy to find and the responsibilities are clear. Developers don't need to be familiar with any external dependency to work on the project.