安卓 MVP : safe use Context in Presenter

Question

在我的应用程序中，我使用 ContentProvider并使用 LoaderManager.LoaderCallbacks<Cursor>.

fragment ( View )

public class ArticleCatalogFragment extends BaseFragment
        implements ArticleCatalogPresenter.View,
        LoaderManager.LoaderCallbacks<Cursor> {

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        return onCreateArticleCatalogLoader(args);
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {        
         data.registerContentObserver(new LoaderContentObserver(new Handler(), loader));
         updateUI(data);        
    }   

    private Loader onCreateArticleCatalogLoader(Bundle args) {
            int categoryId = args.getInt(CATEGORY_ID);
            Loader loader = new ArticleCatalogLoader(this.getActivity(), categoryId);            
            return loader;
    }

}

从MVP的角度我需要:

演示者

public class ArticleCatalogPresenter extends BasePresenter
        implements LoaderManager.LoaderCallbacks<Cursor> {

    View view;

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        return onCreateArticleCatalogLoader(args);
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {        
         data.registerContentObserver(new LoaderContentObserver(new Handler(), loader));
         view.updateUI(data);        
    }               

    private Loader onCreateArticleCatalogLoader(Bundle args) {    
            int categoryId = args.getInt(CATEGORY_ID);
            Loader loader = new ArticleCatalogLoader(context, categoryId); // need Context
            return loader;
    }


    interface View {
        updateUI(Cursor data)
    }

}

因此，我需要 Presenter 中的上下文。

有一些细微差别:

1. Presenter 知道 Context - 这很糟糕，Presenter 不应该知道了解 Android。

2. 在 Presenter 中有上下文会导致内存泄漏。

我现在很苦恼如何避免内存泄露等问题，Presenter中如何传递Context最好，使用Application Context还是Activity/Fragment？

Answer 1

向 Presenter 添加上下文并不好，因为 Presenter 负责业务逻辑。要处理上下文，您需要有 fragment/Activity 在接口(interface)的帮助下使用回调，接口(interface)将说明在处理 View 时 Activity/fragment 需要执行哪些操作。 fragment/Activity 负责提供上下文。

例子:

interface BaseContract {
        interface BaseView {
            //Methods for View
            void onDoSomething();
        }

        interface BasePresenter {
            void doSomething();

        }
    }

    class BaseMainPresenter implements BaseContract.BasePresenter {
        BaseContract.BaseView view;

        BaseMainPresenter(BaseContract.BaseView view) {
            this.view = view;
        }

        @Override
        public void doSomething() {
            if (view != null)
                view.onDoSomething();
        }
    }

    class DemoClass implements BaseContract.BaseView {

        //Create object of Presenter 

        /****
         * Example :
         * BaseMainPresenter baseMainPresenter = new BaseMainPresenter(this);
         */
        @Override
        public void onDoSomething() {
            //Deal with Context here.
        }
    }