初入MVP框架

来源：互联网发布：mac任务栏图标太多编辑：程序博客网时间：2024/06/06 02:20

1.MVP介绍

哥看了很多关于介绍MVP构架博客,都觉得新手不容易理解,SO,决定写一篇MVP的博客.

什么是MVP?

这里写图片描述

Model:数据.负责数据的处理和输出.
VIew:视图.就是UI界面,即Activity.负责返回UI的信息和展示.
Presenter:主持者.接收View的逻辑业务和Model的数据,并处理它们之间的信息,并管理View的状态.
IView:View的接口给予Presenter调用进行UI逻辑的处理与View&Model之间的信息交互.
IPresenter:Presenter的接口,给予View调用,当UI的业务来临时,View通过调用Presenter接口完成展示(处理好的逻辑和数据等).
众所周知写程序都想要高内聚低耦合,在Android中使用MVC构架,Model与View之间的交互导致了模块之间过度的耦合,维护和debug比较困难.从上面的图可以看到MVP很好地隔离了Model和View.View与Model之间无耦合性.这是MVP最大的优点.

2.Example.

我们通过一个简单的用户登入界面进行解析MVP框架.
这里写图片描述

(一)Model

(1)User-实体类

首先写好实体类:两个数据账号和密码.

package com.fengjie.mvptest.model.bean;/** * @author Created by FengJie on 2016/11/7-16:07. * @brief  用户实体类 * @attention */public class User{    private String account;    private String password;    public String getAccount ()    {        return account;    }    public void setAccount ( String account )    {        this.account = account;    }    public String getPassword ()    {        return password;    }    public void setPassword ( String password )    {        this.password = password;    }}

(2)ITOVIew-预留给View的接口

我们指定当Model验证密码后,便需要显示登入成功要将实体类返回到Presenter和在View展现登入失败,登入失败也展现,所以我们先要预留一个接口给View

package com.fengjie.mvptest.model.deal;import com.fengjie.mvptest.model.bean.User;/** * @author Created by FengJie on 2016/11/7-16:10. * @brief   预留接口给View * @attention */public interface IToView{    public void loginSuccess( User user );  //登入成功方法    public void loginFaild();   //登入失败方法}

(3)Biz-事务(数据处理)类

package com.fengjie.mvptest.model.deal;import com.fengjie.mvptest.model.bean.User;/** * @author Created by FengJie on 2016/11/7-16:11. * @brief  对于实体数据和业务逻辑进行处理 * @attention */public class Biz{    public void login ( final String account, final String password, final IToView IToView )    {        new Thread()    //开启子线程模拟耗时操作        {            @Override            public void run ()            {       //open a Thread                try                {                    Thread.sleep(2000);     //delay 2 second                } catch( Exception e )                {                    e.printStackTrace();        //print Exception                }                //Simulate login succeed  situation.                if ( "123".equals(account) && "123".equals(password) )                {                    User user = new User();     //instant of class                    user.setAccount(account);                    user.setPassword(password);                    IToView.loginSuccess(user);    //use interface method.                } else                {                    IToView.loginFaild();   //use interface method.                }            }        }.start();    }}

(二)View

(1)IUserLoginView-View的接口

View的接口主要是确定事务.
首先确定View的事务:负责返回用户和密码的数据,显示和隐藏进度条.

package com.fengjie.mvptest.view;import com.fengjie.mvptest.flag.Flag;/** * @author Created by FengJie on 2016/11/7-16:10. * @brief View数据交互-获得用户名和密码 显示和隐藏进度条 * @attention */public interface IUserLoginView{    public String getAccount ();    public String getPassword ();    public void setProgressBarVisibility ( final int VIEW_FLAG );    public void showToastInfo ( Flag flag);}

(2)UserLoginActivity

实现定义的接口,供于Precenter调用

package com.fengjie.mvptest.view;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.EditText;import android.widget.ProgressBar;import android.widget.Toast;import com.fengjie.mvptest.R;import com.fengjie.mvptest.flag.Flag;import com.fengjie.mvptest.presenter.IPresenter;import com.fengjie.mvptest.presenter.Presenter;import butterknife.BindView;import butterknife.ButterKnife;import butterknife.OnClick;public class UserLoginActivity extends AppCompatActivity implements IUserLoginView{    @BindView ( R.id.id_et_username )    protected EditText et_username;    @BindView ( R.id.id_et_password )    protected EditText et_password;    @BindView ( R.id.id_pb_loading )    protected ProgressBar pgb_loading;    private IPresenter mPresenter = new Presenter(this);    @Override    protected void onCreate ( Bundle savedInstanceState )    {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_login);        ButterKnife.bind(this);    }    /**     * OnClick可以直接绑定点击事件,不必先获取控件     * @param view     */    @OnClick(R.id.id_btn_login)    protected void OnClick(View view) {        mPresenter.loginDeal();    }    @Override    public String getAccount ()    {        return et_username.getText().toString();    }    @Override    public String getPassword ()    {        return et_password.getText().toString();    }    @Override    public void setProgressBarVisibility (final int VIEW_FINAL_VALUE)    {        pgb_loading.setVisibility(VIEW_FINAL_VALUE);    }    @Override    public void showToastInfo ( Flag flag)    {        switch ( flag )        {            case ADD_SUCCEED:                Toast.makeText(this, et_username.getText().toString() + " login success", Toast.LENGTH_SHORT).show();                break;            case ADD_FAILED:                Toast.makeText(this, et_username.getText().toString() + " login failed", Toast.LENGTH_SHORT).show();                break;            default:return;        }    }}

(三)Presenter

(1)IPresenter-Presenter接口

确定View与Model之间的交互事件:就是用户登入处理.

package com.fengjie.mvptest.presenter;/** * @author Created by FengJie on 2016/11/25-13:10. * @brief * @attention */public interface IPresenter{    public void loginDeal ();}

(2)Presenter

处理过程

调用View接口->显示进度条
调用Biz->实现将View返回的数据进行处理,同时通过预留的接口间接对View的下一步UI逻辑进行了处理.
逻辑太清晰了~~~~
也就是说Activity的一个UI业务来临时,只需要通过调用Presenter接口对应的一个方法就能实现处理了!!!这也使得我们的Activity不臃肿.

package com.fengjie.mvptest.presenter;import android.os.Handler;import android.view.View;import com.fengjie.mvptest.flag.Flag;import com.fengjie.mvptest.model.bean.User;import com.fengjie.mvptest.model.deal.Biz;import com.fengjie.mvptest.model.deal.IToView;import com.fengjie.mvptest.view.IUserLoginView;/** * @author Created by FengJie on 2016/11/7-16:07. * @brief   负责完成View与Model间的交互 * @attention */public class Presenter implements IPresenter{    private IUserLoginView mIUserLoginView;     //view interface    private Biz mBiz;                 //model class    private Handler mHandler = new Handler();   //begin thread    public Presenter ( IUserLoginView IUserLoginView )    {        mIUserLoginView = IUserLoginView;        mBiz = new Biz();              //instance Biz class    }    @Override    public void loginDeal ()    {        mIUserLoginView.setProgressBarVisibility(View.VISIBLE);     //show the bar.        mBiz.login(mIUserLoginView.getAccount(), mIUserLoginView.getPassword(), new IToView(){   /**achieve interface*/            /**login succeed**/            @Override            public void loginSuccess ( final User user )            {                mHandler.post(new Runnable()                {                    @Override                    public void run ()                    {                        mIUserLoginView.showToastInfo(Flag.ADD_SUCCEED);    //give flag                        mIUserLoginView.setProgressBarVisibility(View.GONE);                      //hide ProgressBar                    }                });            }            /**login failed**/            @Override            public void loginFaild ()            {                mHandler.post(new Runnable()                {                    @Override                    public void run ()                    {                        mIUserLoginView.showToastInfo(Flag.ADD_FAILED);                        mIUserLoginView.setProgressBarVisibility(View.GONE);                    }                });            }        });    }}

总结

这里写图片描述

View与Presenter关系非常紧密, 相互调用, 并且一一对应. Presenter支持单元测试, View被抽象成若干显示接口, 供Presenter调用, 当View的业务来临只需要调用Presenter便能进行处理,View处理Android逻辑, Presenter处理UI逻辑. View和Presenter的接口信息, 放置在一个逻辑清晰的接口类(合同)中.
简单说View只要返回UI逻辑业务,Model只要处理好数据业务,Presenter只要处理好两者之间的交互并进行展现!

如果有帮助,请赞我的GiuHub和博客

这里写图片描述

源码下载:https://github.com/MadJieJie/MVPTest.git

2 0