MVP 新姿势，记录一下

MVP 全称：Model-View-Presenter。主要逻辑如下：
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。
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。
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：

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：

 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();
    }