Mvp简单实现

首先创建Model，Presenter类

Presenter类：

public class MainActivityPresenter {
    private LoginView loginView;
    private MainActivityModel mainActivityModel;

    public MainActivityPresenter(LoginView loginView) {
        this.loginView = loginView;
        this.mainActivityModel = new MainActivityModel();
    }

    public void login(String username, String password) {
        if (TextUtils.isEmpty(username)) {
            loginView.usernameNull();
            return;
        }
        if (TextUtils.isEmpty(password)) {
            loginView.passwordNull();
            return;
        }
        mainActivityModel.login(username, password, new MainActivityModel.ModelListener() {
            @Override
            public void loginSuccess(String result) {
                loginView.loginSuccess(result);
            }
        });
    }

    public void detach() {
        loginView = null;
    }
}

Model类：

public class MainActivityModel {
    public void login(String username, String password, final ModelListener listener) {
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url("http://qhb.2dyt.com/Bwei/login?username=muhanxi&password=111&postkey=1503d")
                .build();
        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String result = response.body().string();
                listener.loginSuccess(result);
            }
        });
    }

    interface ModelListener {
        public void loginSuccess(String result);
    }
}

MainActivity：

public class MainActivity extends AppCompatActivity implements LoginView {

    private EditText mainUsername;
    private EditText mainPassword;
    private Button mainBtn;
    private MainActivityPresenter presenter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();

    }

    private void initView() {
        mainUsername = (EditText) findViewById(R.id.main_username);
        mainPassword = (EditText) findViewById(R.id.main_password);
        mainBtn = (Button) findViewById(R.id.main_btn);
        presenter = new MainActivityPresenter(this);
        mainBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String username = mainUsername.getText().toString().trim();
                String password = mainPassword.getText().toString().trim();
                presenter.login(username, password);
            }
        });
    }

    @Override
    public void usernameNull() {
        Toast.makeText(this, "usernameNull", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void passwordNull() {
        Toast.makeText(this, "passwordNull", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void loginSuccess(String result) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(MainActivity.this, "loginSuccess", Toast.LENGTH_SHORT).show();
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        presenter.detach();
    }
}

定义接口：

public interface LoginView {
    public void usernameNull();

    public void passwordNull();

    public void loginSuccess(String result);
}

最终是这样的：