什么是 MVP

　在项目中 View 和 Model 并不直接交互，而是使用 Presenter 作为 View 和 Model 之间的桥梁。其中 Presenter 中同时持有 View 层以及 Model 层的 Interface 的引用，而 View 层持有 Presenter 层 Interface 的引用，当 View 层某个页面需要展示某些数据的时候，首先会调用Presenter 层的某个接口，然后 Presenter 层会调用 Model 层请求数据，当 Model 层数据加载成功之后会调用 Presenter 层的回调方法通知 Presenter 层数据加载完毕，最后 Presenter 层再调用 View 层的接口将加载后的数据展示给用户。这就是 MVP 模式的核心过程。

这样分层的好处就是大大减少了Model与View层之间的耦合度。一方面可以使得View层和Model层单独开发与测试，互不依赖。另一方面Model层可以封装复用，可以极大的减少代码量。当然，MVP还有其他的一些优点，这里不再赘述。

这里就给大家随便看看干货板块的功能吧。

布局相当简单。

 1 <?xml version="1.0" encoding="utf-8"?> 2 <android.support.v4.widget.SwipeRefreshLayout 3     xmlns:android="http://schemas.android.com/apk/res/android" 4     xmlns:app="http://schemas.android.com/apk/res-auto" 5     android:id="@+id/swipe_refresh_layout" 6     android:layout_width="match_parent" 7     android:layout_height="match_parent"> 8  9 10     <com.nanchen.aiyagirl.widget.RecyclerViewWithFooter.RecyclerViewWithFooter11         android:id="@+id/recyclerView"12         android:layout_width="match_parent"13         android:layout_height="match_parent"/>14 15 16 </android.support.v4.widget.SwipeRefreshLayout>

　　　干货模块，也就是一个Fragment，里面有一个RecyclerView，支持下拉刷新和上拉加载数据。所以我们的 Presenter 和 View 只需要定义一下简单的方法。

1）加载数据的过程中显示加载的进度条；

2）加载数据成功提醒 Adapter 刷新数据；

3）加载失败谈窗提醒用户相关信息；

4）加载结束隐藏进度条；

 1 package com.nanchen.aiyagirl.module.category; 2  3 import com.nanchen.aiyagirl.base.BasePresenter; 4 import com.nanchen.aiyagirl.base.BaseView; 5 import com.nanchen.aiyagirl.model.CategoryResult; 6  7 /** 8  * Author: nanchen 9  * Email: liushilin520@foxmail.com10  * Date: 2017-04-14  10:1411  */12 13 public interface CategoryContract {14 15     interface ICategoryView extends BaseView{16         17         void getCategoryItemsFail(String failMessage);18 19         void setCategoryItems(CategoryResult categoryResult);20 21         void addCategoryItems(CategoryResult categoryResult);22 23         void showSwipeLoading();24 25         void hideSwipeLoading();26 27         void setLoading();28 29         String getCategoryName();30 31         void noMore();32     }33     34     interface ICategoryPresenter extends BasePresenter{35         36         void getCategoryItems(boolean isRefresh);37     }38 }

编写 Presenter 实现类。

 1 package com.nanchen.aiyagirl.module.category; 2  3 import com.nanchen.aiyagirl.config.GlobalConfig; 4 import com.nanchen.aiyagirl.model.CategoryResult; 5 import com.nanchen.aiyagirl.module.category.CategoryContract.ICategoryView; 6 import com.nanchen.aiyagirl.module.category.CategoryContract.ICategoryPresenter; 7 import com.nanchen.aiyagirl.net.NetWork; 8  9 import rx.Observer;10 import rx.Subscription;11 import rx.android.schedulers.AndroidSchedulers;12 import rx.schedulers.Schedulers;13 14 /**15  * ICategoryPresenter16  * <p>17  * Author: nanchen18  * Email: liushilin520@foxmail.com19  * Date: 2017-04-14  11:1620  */21 22 public class CategoryPresenter implements ICategoryPresenter {23 24     private ICategoryView mCategoryICategoryView;25     private int mPage = 1;26     private Subscription mSubscription;27 28     public CategoryPresenter(ICategoryView androidICategoryView) {29         mCategoryICategoryView = androidICategoryView;30     }31 32     @Override33     public void subscribe() {34         getCategoryItems(true);35     }36 37     @Override38     public void unSubscribe() {39         if (mSubscription != null  && !mSubscription.isUnsubscribed()){40             mSubscription.unsubscribe();41         }42     }43 44     @Override45     public void getCategoryItems(final boolean isRefresh) {46         if (isRefresh) {47             mPage = 1;48             mCategoryICategoryView.showSwipeLoading();49         } else {50             mPage++;51         }52         mSubscription = NetWork.getGankApi()53                 .getCategoryData(mCategoryICategoryView.getCategoryName(), GlobalConfig.CATEGORY_COUNT,mPage)54                 .subscribeOn(Schedulers.io())55                 .observeOn(AndroidSchedulers.mainThread())56                 .subscribe(new Observer<CategoryResult>() {57                     @Override58                     public void onCompleted() {59 60                     }61 62                     @Override63                     public void onError(Throwable e) {64                         mCategoryICategoryView.hideSwipeLoading();65                         mCategoryICategoryView.getCategoryItemsFail(mCategoryICategoryView.getCategoryName()+" 列表数据获取失败！");66                     }67 68                     @Override69                     public void onNext(CategoryResult categoryResult) {70                         if (isRefresh){71                             mCategoryICategoryView.setCategoryItems(categoryResult);72                             mCategoryICategoryView.hideSwipeLoading();73                             mCategoryICategoryView.setLoading();74                         }else {75                             mCategoryICategoryView.addCategoryItems(categoryResult);76                         }77                     }78                 });79 80     }81 }

编写Adapter，用于展示数据。

 1 package com.nanchen.aiyagirl.module.category; 2  3 import android.content.Context; 4 import android.content.Intent; 5 import android.view.View; 6 import android.widget.ImageView; 7  8 import com.bumptech.glide.Glide; 9 import com.nanchen.aiyagirl.ConfigManage;10 import com.nanchen.aiyagirl.R;11 import com.nanchen.aiyagirl.base.adapter.CommonRecyclerAdapter;12 import com.nanchen.aiyagirl.base.adapter.CommonRecyclerHolder;13 import com.nanchen.aiyagirl.base.adapter.ListenerWithPosition;14 import com.nanchen.aiyagirl.model.CategoryResult;15 import com.nanchen.aiyagirl.model.CategoryResult.ResultsBean;16 import com.nanchen.aiyagirl.module.web.WebViewActivity;17 import com.nanchen.aiyagirl.utils.TimeUtil;18 19 /**20  * Author: nanchen21  * Email: liushilin520@foxmail.com22  * Date: 2017-04-14  10:2123  */24 25 class CategoryRecyclerAdapter extends CommonRecyclerAdapter<CategoryResult.ResultsBean> implements ListenerWithPosition.OnClickWithPositionListener<CommonRecyclerHolder>{26 27     CategoryRecyclerAdapter(Context context) {28         super(context, null, R.layout.item_category);29     }30 31     @Override32     public void convert(CommonRecyclerHolder holder, ResultsBean resultsBean) {33         if (resultsBean != null) {34             ImageView imageView = holder.getView(R.id.category_item_img);35             if (ConfigManage.INSTANCE.isListShowImg()) { // 列表显示图片36                 imageView.setVisibility(View.VISIBLE);37                 String quality = "";38                 if (resultsBean.images != null && resultsBean.images.size() > 0) {39                     switch (ConfigManage.INSTANCE.getThumbnailQuality()) {40                         case 0: // 原图41                             quality = "";42                             break;43                         case 1: //44                             quality = "?imageView2/0/w/400";45                             break;46                         case 2:47                             quality = "?imageView2/0/w/190";48                             break;49                     }50                     Glide.with(mContext)51                             .load(resultsBean.images.get(0) + quality)52                             .placeholder(R.mipmap.image_default)53                             .error(R.mipmap.image_default)54                             .into(imageView);55                 } else { // 列表不显示图片56                     Glide.with(mContext).load(R.mipmap.image_default).into(imageView);57                 }58             } else {59                 imageView.setVisibility(View.GONE);60             }61 62             holder.setTextViewText(R.id.category_item_desc, resultsBean.desc == null ? "unknown" : resultsBean.desc);63             holder.setTextViewText(R.id.category_item_author, resultsBean.who == null ? "unknown" : resultsBean.who);64             holder.setTextViewText(R.id.category_item_time, TimeUtil.dateFormat(resultsBean.publishedAt));65             holder.setTextViewText(R.id.category_item_src, resultsBean.source == null ? "unknown" : resultsBean.source);66             holder.setOnClickListener(this, R.id.category_item_layout);67         }68     }69 70     @Override71     public void onClick(View v, int position, CommonRecyclerHolder holder) {72 //        Toasty.info(mContext,"跳转到相应网页！", Toast.LENGTH_SHORT,true).show();73         Intent intent = new Intent(mContext, WebViewActivity.class);74         intent.putExtra(WebViewActivity.GANK_TITLE, mData.get(position).desc);75         intent.putExtra(WebViewActivity.GANK_URL, mData.get(position).url);76         mContext.startActivity(intent);77     }78 }

最后当然是 Fragment。

package com.nanchen.aiyagirl.module.category;import android.os.Bundle;import android.support.v4.widget.SwipeRefreshLayout;import android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener;import android.support.v7.widget.LinearLayoutManager;import com.nanchen.aiyagirl.R;import com.nanchen.aiyagirl.base.BaseFragment;import com.nanchen.aiyagirl.model.CategoryResult;import com.nanchen.aiyagirl.module.category.CategoryContract.ICategoryPresenter;import com.nanchen.aiyagirl.module.category.CategoryContract.ICategoryView;import com.nanchen.aiyagirl.widget.RecyclerViewDivider;import com.nanchen.aiyagirl.widget.RecyclerViewWithFooter.OnLoadMoreListener;import com.nanchen.aiyagirl.widget.RecyclerViewWithFooter.RecyclerViewWithFooter;import butterknife.BindView;import es.dmoral.toasty.Toasty;/**
 * 主页轮播下面的Fragment
 * <p>
 * Author: nanchen
 * Email: liushilin520@foxmail.com
 * Date: 2017-04-14  9:46 */public class CategoryFragment extends BaseFragment implements ICategoryView, OnRefreshListener, OnLoadMoreListener {    public static final String CATEGORY_NAME = "com.nanchen.aiyagirl.module.category.CategoryFragment.CATEGORY_NAME";
    @BindView(R.id.recyclerView)
    RecyclerViewWithFooter mRecyclerView;
    @BindView(R.id.swipe_refresh_layout)
    SwipeRefreshLayout mSwipeRefreshLayout;    private String categoryName;    private CategoryRecyclerAdapter mAdapter;    private ICategoryPresenter mICategoryPresenter;    public static CategoryFragment newInstance(String mCategoryName) {
        CategoryFragment categoryFragment = new CategoryFragment();
        Bundle bundle = new Bundle();
        bundle.putString(CATEGORY_NAME, mCategoryName);
        categoryFragment.setArguments(bundle);        return categoryFragment;
    }


    @Override    protected int getContentViewLayoutID() {        return R.layout.fragment_category;
    }

    @Override    protected void init() {
        mICategoryPresenter = new CategoryPresenter(this);

        categoryName = getArguments().getString(CATEGORY_NAME);

        mSwipeRefreshLayout.setOnRefreshListener(this);

        mAdapter = new CategoryRecyclerAdapter(getActivity());

        mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        mRecyclerView.addItemDecoration(new RecyclerViewDivider(getActivity(), LinearLayoutManager.HORIZONTAL));
        mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.setOnLoadMoreListener(this);
        mRecyclerView.setEmpty();

        mICategoryPresenter.subscribe();

    }

    @Override    public void onDestroy() {        super.onDestroy();        if (mICategoryPresenter != null) {
            mICategoryPresenter.unSubscribe();
        }
    }

    @Override    public void onRefresh() {
        mICategoryPresenter.getCategoryItems(true);
    }

    @Override    public void onLoadMore() {
        mICategoryPresenter.getCategoryItems(false);
    }

    @Override    public void getCategoryItemsFail(String failMessage) {        if (getUserVisibleHint()) {
            Toasty.error(this.getContext(), failMessage).show();
        }
    }

    @Override    public void setCategoryItems(CategoryResult categoryResult) {
        mAdapter.setData(categoryResult.results);
    }

    @Override    public void addCategoryItems(CategoryResult categoryResult) {
        mAdapter.addData(categoryResult.results);

    }

    @Override    public void showSwipeLoading() {
        mSwipeRefreshLayout.setRefreshing(true);
    }

    @Override    public void hideSwipeLoading() {
        mSwipeRefreshLayout.setRefreshing(false);
    }

    @Override    public void setLoading() {
        mRecyclerView.setLoading();
    }

    @Override    public String getCategoryName() {        return this.categoryName;
    }

    @Override    public void noMore() {
        mRecyclerView.setEnd("没有更多数据");
    }

}

原文链接：http://www.apkbus.com/blog-708270-63577.html

MVP运用

什么是 MVP