Use of MVP in Android

What exactly is the MVP?

The MVP is that pattern that permits isolate introduction layer from the logic, with the goal that how to interface functions get isolated from the how we exhibit it on the screen. At first, MVP example can accomplish a similar logic that may be totally unique and exchangeable perspectives. Like most of the architectural patterns, MVP is open for a lot of various experiments. 

1.It separates the code for views, which is used for showing for the user like list, buttons, labels etc. from the business logic that is triggered on user interaction with a view which we call a presenter. Data that is shown in the view is provided by another separate module which is called as a model. 

2. Communication between the view and modal takes place through presenter i.e. view and modal can't have each other's reference.

3. By using this design we can make changes in a component without changing the code of other components.

4. The code is maximized that can be tested with automation. 

Andriod activity and MVP

Andriod activity gives the functionality of view like we do things setContentView() in OnCreate(). Activities maintain andriod life cycle events such as onCreate() onResume() etc which will be business logic i.e presenter.

Another way of showing how they are entangled is:-

1. registers the listeners for the user interaction with the view.

2. Perform the required actions on user interactions with business logic.

Implementation of MVP

The presenter's interaction with model gets handled by separate manager class. It follows the contract of VideoListManager

android {
  public interface VideoListManager {

    interface VideoListManagerListener {
        void onVideoListUpdate(VideoListInfo videoListInfo);
    }

    void getVideosWithNewSorting(int sortType);
    void registerListener(VideoListManagerListener videoListManagerListener);

    void unRegisterListener();

}
 

View 

Videos are displayed by use of ListView or ExpandableListView. The use of ViewMvp interface returns root view to the presenter that is further used for communications among presenter and view for user interactions.

We use ListView so we need to implement by using adapters.

android {
  @Override
    public void bindVideoList(VideoListInfo videoListInfo)
    {
        mVideoListAdapter.bindVideoList(videoListInfo);
        mVideoListAdapter.notifyDataSetChanged();
    }

    @Override
    public View getRootView() {
        return mFragemntVideoListView;
    }
 

Presenter 

It is the important part of the application, that initializes view and model and it also set up the communication framework for handling users interactions and model data changes

android {
 VideoListingViewImpl mVideoListingViewImpl;
VideoListManagerImpl mVideoListManagerImpl;


protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mVideoListingViewImpl = new VideoListingViewImpl(this, null); //initializing the view

        setContentView(mVideoListingViewImpl.getRootView()); //setting the setContentView from the rootView returned

        mViewPager = mVideoListingViewImpl.getViewPager();

        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this);
        mSortingType = settings.getInt(SORT_TYPE_PREFERENCE_KEY, 3);
        mVideoListManagerImpl = new VideoListManagerImpl(this, mSortingType);// initialising the model
        mVideoListManagerImpl.registerListener(this); // registering the listerner to get video list update events
    }