本blog介绍mvp模式的特点与优点，为了方便理解 举了用mvp模式实现的两个例子，例一偏向简单用于原理说明，例二应用现在比较火的Retrofit和RXJava进行网络数据请求的mvp模式实例。

1、MVP模式：

 

2、MVP模式  VS  MVC模式

（1）各个层之间通过接口协议进行沟通。

（2）View和Model不再进行直接交互

 

3、MVP优势：

       （1）View和Model之间的耦合度降低，使各自更关注自身业务。

       （2）便于单元测试。

       （3）代码复用率提高。

       （4）代码框架更适用于快速迭代开发。

4、－－－－－－－－－－－－－－－－－－－－－－－－－－－－－实例1

     

     项目结构：

View层：

public class BaseViewActivity extends AppCompatActivity implements BaseView{
    private BasePresenterImpl mPresenter;
    boolean flag;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mPresenter = new BasePresenterImpl(this);

        Log.e("JS","进入 view 层  1");
        //开始请求服务
        mPresenter.loadData();
        Log.e("JS","进入 view 层  2");
        //加载完成
        mPresenter.loadResult();
    }

    @Override
    public void loading() {
        Log.e("JS","开启  进入view层 iterface 事件");
    }

    @Override
    public void cancelLoading() {
        Log.e("JS","结束  进入view层 iterface 事件");
    }
}

//UI逻辑接口，一般由activity、fragment实现
public interface BaseView {
    //显示加载进度
    void loading();

    //隐藏加载进度
    void cancelLoading();
}

presenter层：

public class BasePresenterImpl implements BasePresenter{
    private BaseView mView;
    private BaseModel mModel;

    public BasePresenterImpl(BaseView view){
        mModel = new BaseModelimpl();
        this.mView = view;
    }

    // 调用view层和model层来 加载数据
    public void loadData(){
        Log.e("JS","model/view------->presenter ");
        mView.loading();//访问view层
        mModel.RequestService();//访问model层

        Log.e("JS","-----可得到 view和model return 的数据－－－－－－－");
    }




    @Override
    public void loadResult() {
        Log.e("JS","presenter --------->  view ");
        mView.cancelLoading();
    }
}

/**处理业务逻辑
 * Created by apple on 17/4/27.
 */

public interface BasePresenter {
    //加载数据结果
    void loadResult();
}

Model层：

public class BaseModelimpl implements BaseModel {
    @Override
    public void RequestService() {
        Log.e("JS","开启  进入model层     interface");
    }
}

public interface BaseModel {
    //请求服务器
    void RequestService();

}

打印信息：

实例2－－－－－－－－－－－－－－－－－

retrofit和rxJava结合的mvp实例

1、view层接口

import com.example.apple.retrofit.MVP.bean.IpBean;

/**
 * Created by apple on 17/5/4.
 */

public interface interView {
    public void showInfo(IpBean ipBean);
    public void showError(Throwable e);
}

view层activity

import com.example.apple.retrofit.MVP.bean.IpBean;
import com.example.apple.retrofit.MVP.presenter.Presenter;
import com.example.apple.retrofit.MVP.presenter.interPresenter;
import com.example.apple.retrofit.R;

/**
 * Created by apple on 17/5/4.
 */

public class MainActivity extends Activity implements interView{
    private TextView ipInfo;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ipInfo = (TextView) findViewById(R.id.ipInfo);
        interPresenter presenter = new Presenter(this);
        presenter.queryIpInfo("121.33.6.228");//调用presenter层的接口方法
    }

    @Override
    public void showInfo(IpBean ipBean) {
        String aa = ipBean.area+ipBean.city+ipBean.country+ipBean.ip+ipBean.region;
        Log.e("jj",aa);
        ipInfo.setText(aa);
    }

    @Override
    public void showError(Throwable e) {

    }
}

2、presenter层接口

public interface interPresenter {
    public void queryIpInfo(String ip);
}

presenter实现类

public class Presenter implements interPresenter{
    //在presenter层，引入model层和view层。
    private interView viewActivity;
    private interModel model;

    public Presenter(MainActivity viewActivity){
        this.viewActivity = viewActivity;
        model = new Model();
    }

    @Override
    public void queryIpInfo(String ip) {
        //观察者位于presenter层，通知主线程

        Subscriber<ApiBean<IpBean>> mySubscriber = new Subscriber<ApiBean<IpBean>>() {
            @Override
            public void onCompleted() {

            }

            @Override
            public void onError(Throwable e) {
                viewActivity.showError(e);
            }

            @Override
            public void onNext(ApiBean<IpBean> ipBeanApiBean) {
                //获取来自被观察者model层传来的ipBeanApiBean，并调用view层方法
                viewActivity.showInfo(ipBeanApiBean.data);
            }
        };
        model.queryIpInfo(ip,mySubscriber);//调用model接口方法
    }
}

3、model层接口

public interface interModel {
    public void queryIpInfo(String ip, Subscriber<ApiBean<IpBean>> subscriber);
}

model层retrofit请求接口（此请求采用get方式）

public interface InterfRetrofit {
    @GET("service/getIpInfo.php")
    Call<ApiBean<IpBean>> getMessage(@Query("ip") String ip);
}

model层实现类

public class Model implements interModel{
    @Override
    public void queryIpInfo(final String ip, Subscriber<ApiBean<IpBean>> subscriber) {
        //被观察者做耗时操作，位于model层
        Observable<ApiBean<IpBean>> myObserverble =
                Observable.create(new Observable.OnSubscribe<ApiBean<IpBean>>() {
                    @Override
                    public void call(Subscriber<? super ApiBean<IpBean>> subscriber) {
                        //在rxjava的observable中，添加一个retrofit，进行网络请求 具体耗时操作由它执行
                        String URL_BASE = "http://ip.taobao.com";
                        Retrofit retrofit = new Retrofit.Builder()
                                .baseUrl(URL_BASE)
                                .addConverterFactory(GsonConverterFactory.create())
                                .build();
                        InterfRetrofit interfRetrofit = retrofit.create(InterfRetrofit.class);
                        Call<ApiBean<IpBean>> call = interfRetrofit.getMessage(ip);
                        try {
                            Response<ApiBean<IpBean>> response = call.execute();
                            ApiBean<IpBean> apiResponse = response.body();
                            //将apiResponse传给观察者presenter
                            subscriber.onNext(apiResponse);
                        } catch (IOException e) {
                            e.printStackTrace();
                            subscriber.onError(e);
                        }finally {
                            subscriber.onCompleted();
                        }

                    }
                }).subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread());
        myObserverble.subscribe(subscriber);
    }
}

4、数据解析bean层

public class ApiBean<T> implements Serializable {
    //结果
    public int code;
    //数据
    public T data;
}

import com.google.gson.annotations.SerializedName;

public class IpBean {
    //国家
    public String country;
    //国家代码
    @SerializedName("country_id")
    public String countryId;
    //地区
    public String area;
    //地区代码
    @SerializedName("area_id")
    public String areaId;
    //省份
    public String region;
    //省份代码
    @SerializedName("region_id")
    public String regionId;
    //城市
    public String city;
    //城市代码
    @SerializedName("city_id")
    public String cityId;
    //区
    public String county;
    //区号
    @SerializedName("county_id")
    public String countyId;
    //运营商
    public String isp;
    //运营商代码
    @SerializedName("isp_id")
    public String ispId;
    //IP地址
    public String ip;
}