android MVP 设计模式

 MVP 全称：Model-View-Presenter。主要逻辑如下：

 MVP 全称：Model-View-Presenter。主要逻辑如下：

1. View。也就是Android中的Activity。同时需要创建一个View的抽象接口View interface。需要View实现的接口，View通过View interface与Presenter进行交互，降低耦合。

2. Model。用来操做实际数据（譬如数据存储等）。有时也需要创建一个Model的抽象接口Model interface用来降低耦合。

3. Presenter。作为View与Model交互的中间纽带，处理与用户交互的负责逻辑。  

   优点如下：(1)降低耦合度

     (2)模块职责划分明显

     (3)利于测试驱动开发

     (4)代码复用

     (5)隐藏数据

     (6)代码灵活性
缺点：  需要增加很多类。
  
  但是相比优点而言，缺点可以忽略。


 具体的demo代码如下：


MainActivity:

public class MainActivity extends Activity implements IUserView,

OnClickListener {

private TextView showView;

private EditText username_et;

private EditText password_et;

private Button login_btn;

private Button getuserinfo_btn;

private Presenter pre;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

bindView();

setListener();

}

private void setListener() {

login_btn.setOnClickListener(this);

getuserinfo_btn.setOnClickListener(this);

}

private void bindView() {

showView = (TextView) this.findViewById(id.showView);

username_et = (EditText) this.findViewById(id.username_et);

password_et = (EditText) this.findViewById(id.password_et);

login_btn = (Button) this.findViewById(id.login_btn);

getuserinfo_btn = (Button) this.findViewById(id.getuserinfo_btn);

pre = new Presenter(this);

}

@Override

public void setUser(UserInfo info) {

showView.setText("用户名为:" + info.getUsername() + ",密码为:"

+ info.getPassword());

}

@Override

public UserInfo getUser() {

UserInfo info = new UserInfo();

String password = password_et.getText().toString().trim();

String username = username_et.getText().toString().trim();

if (TextUtils.isEmpty(username)) {

toast("用户名不能为空");

return null;

}

if (TextUtils.isEmpty(password)) {

toast("密码不能为空");

return null;

}

info.setPassword(password);

info.setUsername(username);

return info;

}

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.login_btn:

pre.saveInfo(getUser());

break;

case id.getuserinfo_btn:

pre.getUserInfo(); 

break;

default:

break;

}

}

private void toast(String msg) {

Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();

}

}

实体bean：

创建UserInfo 实体类

public class UserInfo {

private String username;

private String password;

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

@Override

public String toString() {

// TODO Auto-generated method stub

return username + ":" + password;

}

}

Model 抽象层

public interface UserModel {

public UserInfo getUserInfo();

public void setUserInfo(UserInfo info);

}

 

Model具体实现层：

public class UserModelImp implements UserModel {

UserInfo info = new UserInfo();

@Override

public UserInfo getUserInfo() {

return info;

}

@Override

public void setUserInfo(UserInfo info) {

this.info = info;

}

}

 

数据交互实现层：

public class Presenter {

private UserModel userModel;

private IUserView IuserView;

public Presenter(IUserView userView) {

this.IuserView = userView;

userModel = new UserModelImp();

}

public void saveInfo(UserInfo info) {

userModel.setUserInfo(info);

}

public void getUserInfo() {

IuserView.setUser(userModel.getUserInfo());

}

}

 View数据抽象层：

public interface IUserView {

public void setUser(UserInfo info);

public UserInfo getUser();

}