Android MVP:Presenter中的安全使用上下文 [英] Android MVP: safe use Context in Presenter

问题描述

在我的应用中，我使用ContentProvider并使用LoaderManager.LoaderCallbacks<Cursor>.

In my app I work with ContentProvider and use LoaderManager.LoaderCallbacks<Cursor>.

片段(查看)

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的角度来看，我需要:

From point of view MVP I need:

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，我需要在Presenter中使用上下文.

So, I need a context in Presenter.

有一些细微差别:

1. 演示者了解上下文-这很糟糕，演示者不应该 了解Android.

1. Presenter know about the Context - it is bad, Presenter should not know about the Android.

在Presenter中具有上下文会导致内存泄漏.

Having a Context in Presenter can lead to memory leak.

我现在担心如何避免出现诸如内存泄漏之类的问题，以及如何最好地在Presenter中传递Context，使用Application Context或Activity/Fragment?

I am now worried about how to avoid problems such as memory leaks, and how best pass Context in Presenter, use Application Context or Activity/Fragment?

推荐答案

向Presenter添加上下文不是很好，因为Presenter负责业务逻辑.要处理上下文，您需要具有片段/活动" 在接口的帮助下利用回调，该接口将说明在处理视图时活动/片段需要执行哪些操作. 片段/活动负责提供上下文.

Adding context to Presenter is not good since, the presenter is responsible for business logic. To deal with context, you need to have the Fragment/Activities make use of Callbacks with the help of interfaces which will state what actions need to be perform by the activity/fragment when dealing with views. Fragment / Activities are responsible to provide Context.

示例:

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.
        }
    }

这篇关于Android MVP:Presenter中的安全使用上下文的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！