Android MVP模式初步认识

一、MVP与MVC

MVC全名是Model View Controller，是模型(model)－视图(view)－控制器(controller)的缩写

MVP 全称：Model-View-Presenter

MVP 是从经典的模式MVC演变而来，它们的基本思想有相通的地方：Controller/Presenter负责逻辑的处理，Model提供数据，View负责显示。
MVP与MVC有着一个重大的区别：在MVP中View并不直接使用Model，它们之间的通信是通过Presenter (MVC中的Controller)来进行的，所有的交互都发生在Presenter内部，而在MVC中View会直接从Model中读取数据而不是通过 Controller。

二、MVP模式实现方式

三、实例
现在通过一个实例来对MVP模式有个初步了解。

程序逻辑：将一段网络请求的字符串显示在界面
1、MVP之V：UI实现view的方法，引用Presenter

UI

package com.wj.myapplication.ui;import android.app.Activity;import android.os.Bundle;import android.support.annotation.Nullable;import android.widget.TextView;import com.wj.myapplication.R;import com.wj.myapplication.model.MvpModelBean;import com.wj.myapplication.presenter.MvpPresenter;import com.wj.myapplication.view.MvpView;import butterknife.Bind;import butterknife.ButterKnife;/** * for: mvp简单使用 Presenter负责逻辑的处理，Model提供数据，View负责显示 * MVP与MVC有着一个重大的区别：在MVP中View并不直接使用Model， * 它们之间的通信是通过Presenter (MVC中的Controller)来进行的， * 所有的交互都发生在Presenter内部，而在MVC中View会直接从Model中读取数据而不是通过 Controller。 * UI实现View方法，引用Presenter * Created by wj on 2017/7/10. */public class MVPActivity extends Activity implements MvpView{    @Bind(R.id.tv_mvp)    TextView tvMvp;    private MvpPresenter mvpPresenter;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_mvp);        ButterKnife.bind(this);        mvpPresenter = new MvpPresenter(this);        //通知presenter获取数据        mvpPresenter.loadData();    }    /**     * 将数据显示在界面     * @param mvpModelBean     */    @Override    public void showStr(MvpModelBean mvpModelBean) {        tvMvp.setText(mvpModelBean.getStr());    }}

view

package com.wj.myapplication.view;import com.wj.myapplication.model.MvpModelBean;/** * for: 处理界面业务需要哪些方法 * Created by wangjian on 2017/7/10. */public interface MvpView {    /**     * mvp页面的业务只有一个，显示一段话     */    void showStr(MvpModelBean mvpModelBean);}

2、MVP之P：Presenter调用model实现数据获取

IMVPPresenter

package com.wj.myapplication.presenter;import com.wj.myapplication.model.MvpModelBean;/** * for: 此接口的作用是连接model * Created by wangjian on 2017/7/10. */public interface IMvpPresenter {    void loadDataSuccess(MvpModelBean mvpModel);    void loadDataFail();}

Presenter

package com.wj.myapplication.presenter;/** * for: 连接view * Created by wangjian on 2017/7/10. */public interface Presenter<V> {    void attach(V view);    void detach();}

MVPPresenter

package com.wj.myapplication.presenter;import com.wj.myapplication.model.MVPModel;import com.wj.myapplication.model.MvpModelBean;import com.wj.myapplication.view.MvpView;/** * for:View和Model的桥梁，它从Model层检索数据后，返回给View层 * Created by wangjian on 2017/7/10. */public class MvpPresenter implements IMvpPresenter,Presenter<MvpView>{    /**     * view来自view层引用presenter     * @param view     */    private MvpView mvpView;    /**     * model通过创建一个model的引用     */    private MVPModel mvpModel;    public MvpPresenter(MvpView view) {        attach(view);        mvpModel = new MVPModel(this);    }    /**     * 通知model去获取数据     */    public void loadData(){        mvpModel.loadData();    }    @Override    public void attach(MvpView view) {        this.mvpView = view;    }    @Override    public void detach() {        this.mvpView = null;    }    /**     * 通知view去改变界面     * @param mvpModel     */    @Override    public void loadDataSuccess(MvpModelBean mvpModel) {        mvpView.showStr(mvpModel);    }    @Override    public void loadDataFail() {    }}

3、MVP之M：Model逻辑实现，回调Presenter方法

model

package com.wj.myapplication.model;import com.wj.myapplication.presenter.IMvpPresenter;/** * for: Model逻辑实现，回调Presenter方法 * Created by wangjian on 2017/7/10. */public class MVPModel {    private IMvpPresenter iMvpPresenter;    public MVPModel(IMvpPresenter iMvpPresenter){        this.iMvpPresenter = iMvpPresenter;    }    /**     * 获取数据并回调     */    public void loadData(){        MvpModelBean mvpModelBean = new MvpModelBean();        //可以通过网络获取数据        mvpModelBean.setStr("this string is from MVP ");        iMvpPresenter.loadDataSuccess(mvpModelBean);    }}

modelbean

package com.wj.myapplication.model;/** * for: * Created by wangjian on 2017/7/10. */public class MvpModelBean {    private String str;    public String getStr() {        return str;    }    public void setStr(String str) {        this.str = str;    }}