M層
package com.example.mvp2;

/**
 * author:Created by MingShao on 2017/12/1.
 */

public interface LoginModel {
    public interface OnloginFinishListener{
        void showProgress();
        void hideProgress();
        void onSuccess();
        void inFailed();
    }
    void login(String username,String userpwd,OnloginFinishListener onloginFinishListener);
}

------------------------------------------------------------

package
 
 com.example.mvp2;


import android.os.Handler;
import android.text.TextUtils;

/**
 * author:Created by MingShao on 2017/12/1.
 */

public class LoginModelpi implements LoginModel{

    @Override
    public void login(String username, String userpwd, final OnloginFinishListener onloginFinishListener) {
        if
 
(TextUtils.isEmpty(username)){
            onloginFinishListener.inFailed();
        return;
        }
        if(TextUtils.isEmpty(userpwd)){
            onloginFinishListener.inFailed();
            return;
        }

        new Handler().postDelayed(new Runnable() {
            @Override
            public
 
 void run() {
            onloginFinishListener.onSuccess();
            }
        },5000);
    }
}

V層
package com.example.mvp2;

/**
 * author:Created by MingShao on 2017/12/2.
 */

public interface LoginView {
    void showProgress();
    void hideProgress();
    void onSuccess();
    void inFailed();
}


------------------------------------------------------------
package com.example.mvp2;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements LoginView{

    private EditText etnam;
    private EditText etpwd;
    private ProgressBar pb;
    private LoginPresenter loginPresenter;
    private Button bt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        etnam = findViewById(R.id.etname);
        etpwd = findViewById(R.id.etpwd);
        bt = findViewById(R.id.bt);
        pb = findViewById(R.id.pb);
        loginPresenter = new LoginPresenterImpl(this);
        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                loginPresenter.verfiyLogin(etnam.getText().toString(),etpwd.getText().toString());
            }
        });
    }

    @Override
    public void showProgress() {
       pb.setVisibility(View.VISIBLE);
    }

    @Override
    public void hideProgress() {
    pb.setVisibility(View.GONE);
    }

    @Override
    public void onSuccess() {
        Toast.makeText(this,"登陸成功",Toast.LENGTH_SHORT).show();;
    }

    @Override
    public void inFailed() {
    etnam.setError("使用者名稱錯誤");
    etpwd.setError("密碼錯誤");
    Toast.makeText(this,"登陸失敗",Toast.LENGTH_SHORT).show();
    }
}

P層
package com.example.mvp2;

/**
 * author:Created by MingShao on 2017/12/1.
 */

public interface LoginPresenter {
    void verfiyLogin(String username,String userpwd);
}


------------------------------------------------------------
package com.example.mvp2;

/**
 * author:Created by MingShao on 2017/12/1.
 */

public class LoginPresenterImpl implements LoginPresenter,LoginModel.OnloginFinishListener {

    private final LoginModel loginModel;
    LoginView loginView;

    public LoginPresenterImpl(LoginView loginView) {
        this.loginView = loginView;
        loginModel = new LoginModelpi();
    }

    @Override
    public void verfiyLogin(String username, String userpwd) {
        if(loginView==null)
            return;
            loginModel.login(username,userpwd,this);

    }

    @Override
    public void showProgress() {
        loginView.showProgress();
    }

    @Override
    public void hideProgress() {
        loginView.hideProgress();
    }

    @Override
    public void onSuccess() {
        loginView.onSuccess();
    }

    @Override
    public void inFailed() {
        loginView.inFailed();
    }
}

M層佈局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.mvp2.MainActivity">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/etname"
        android:hint="請輸入使用者名稱"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/etpwd"
        android:hint="請輸入密碼"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/bt"
        android:text="登陸"
        />
    <ProgressBar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/pb"
        />

</LinearLayout>