设计模式——MVP

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MVP介绍

MVP结构图

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MVP各层

M层：实体模型和业务逻辑
V层：对应于Activity，负责View的绘制以及与用户交互
P层：负责完成View于Model间的交互，减少了Activity的职责，简化了Activity中的代码，将复杂的逻辑代码提取到了Presenter中进行处理。

用户登录示例

效果图

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项目目录如图

这里写图片描述

View层

布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:gravity="center"    android:orientation="vertical" >    <EditText        android:id="@+id/et_name"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="用户名" />    <EditText        android:id="@+id/et_passwd"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="密码"        android:password="true" />    <Button        android:id="@+id/bt_login"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="登录" /></LinearLayout>

需要定义一个接口view让Presenter操作View。此接口需要的功能有：登录成功跳转到主界面，登录失败给用户提醒，显示加载对话框，取消加载对话框，获取用户输入的用户名和密码。此接口为：ILoginView

package com.sjb.mvpdemo.view;import com.sjb.mvpdemo.model.entity.UserEntity;public interface ILoginView {    void toMainActivity(UserEntity user);    void loginFailed();    void showLoadingDialog();    void dismissLoadingDialog();    String getUserName();    String getPasswd();}

登录Activity需要实现此接口，然后通过Presenter调用接口中的方法，与View交互。

package com.sjb.mvpdemo.view.activity;import com.sjb.mvpdemo.R;import com.sjb.mvpdemo.R.id;import com.sjb.mvpdemo.R.layout;import com.sjb.mvpdemo.R.menu;import com.sjb.mvpdemo.model.entity.UserEntity;import com.sjb.mvpdemo.presenter.LoginPresenter;import com.sjb.mvpdemo.view.ILoginView;import android.support.v7.app.ActionBarActivity;import android.app.ProgressDialog;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class LoginActivity extends ActionBarActivity implements ILoginView,        OnClickListener {    private EditText et_username, et_passwd;    private Button bt_login;    private ProgressDialog progressDialog;    private LoginPresenter mLoginPresenter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initViews();        initDatas();        initEvents();    }    private void initEvents() {        bt_login.setOnClickListener(this);    }    private void initDatas() {        progressDialog = new ProgressDialog(this);        progressDialog.setTitle("登录中。。。");        mLoginPresenter=new LoginPresenter(this);    }    private void initViews() {        et_username = (EditText) findViewById(R.id.et_name);        et_passwd = (EditText) findViewById(R.id.et_passwd);        bt_login = (Button) findViewById(R.id.bt_login);    }    @Override    public void toMainActivity(UserEntity user) {        Toast.makeText(this, "登录成功，跳转界面", Toast.LENGTH_SHORT).show();    }    @Override    public void loginFailed() {        Toast.makeText(this, "登录失败", Toast.LENGTH_SHORT).show();    }    @Override    public void showLoadingDialog() {        progressDialog.show();    }    @Override    public void dismissLoadingDialog() {        progressDialog.dismiss();    }    @Override    public void onClick(View v) {        switch (v.getId()) {        case R.id.bt_login:            mLoginPresenter.login();            break;        }    }    @Override    public String getUserName() {        return et_username.getText().toString().trim();    }    @Override    public String getPasswd() {        return et_passwd.getText().toString().trim();    }}

Presenter层

通过获取View层LoginActivity传来的ILoginModel来操作View，获取model对象调用业务逻辑。

package com.sjb.mvpdemo.presenter;import android.os.Handler;import com.sjb.mvpdemo.listener.IOnLoginListener;import com.sjb.mvpdemo.model.ILoginModel;import com.sjb.mvpdemo.model.LoginModelImpl;import com.sjb.mvpdemo.model.entity.UserEntity;import com.sjb.mvpdemo.view.ILoginView;public class LoginPresenter {    private ILoginView mLoginView;// 操作登录页面    private ILoginModel mLoginModel;    private Handler myHandler = new Handler();    public LoginPresenter(ILoginView loginView) {        this.mLoginView = loginView;        mLoginModel = new LoginModelImpl();    }    public void login() {        UserEntity user=new UserEntity(mLoginView.getUserName(), mLoginView.getPasswd());         mLoginView.showLoadingDialog();        mLoginModel.login(user, new IOnLoginListener() {            @Override            public void onSuccess(final UserEntity user) {                // TODO Auto-generated method stub                myHandler.post(new Runnable() {                    @Override                    public void run() {                        mLoginView.dismissLoadingDialog();                        mLoginView.toMainActivity(user);                    }                });            }            @Override            public void onFailed() {                myHandler.post(new Runnable() {                    @Override                    public void run() {                        mLoginView.dismissLoadingDialog();                        mLoginView.loginFailed();                    }                });            }        });    }}

model层

实体类UserEntity

package com.sjb.mvpdemo.model.entity;import java.io.Serializable;//MVP中的实体类(属于Model)public class UserEntity implements Serializable{    private String userName;    private String passwd;    public UserEntity(String userName, String passwd) {        super();        this.userName = userName;        this.passwd = passwd;    }    public String getUserName() {        return userName;    }    public void setUserName(String userName) {        this.userName = userName;    }    public String getPasswd() {        return passwd;    }    public void setPasswd(String passwd) {        this.passwd = passwd;    }}

定义一个Model接口ILoginModel添加一个login方法

package com.sjb.mvpdemo.model;import com.sjb.mvpdemo.listener.IOnLoginListener;import com.sjb.mvpdemo.model.entity.UserEntity;public interface ILoginModel {    void login(UserEntity user,IOnLoginListener listener);}

此model接口的实现类LoginModelImpl

package com.sjb.mvpdemo.model;import com.sjb.mvpdemo.listener.IOnLoginListener;import com.sjb.mvpdemo.model.entity.UserEntity;public class LoginModelImpl implements ILoginModel {    @Override    public void login(final UserEntity user, final IOnLoginListener listener) {        new Thread() {            public void run() {                try {                    Thread.sleep(2000);                } catch (InterruptedException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }                //本地模拟用户名密码是否正确                if (user.getUserName().equals("user")                        && user.getPasswd().equals("123")) {                    listener.onSuccess(user);                } else {                    listener.onFailed();                }            };        }.start();    }}

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