Android MVP 学习

╰半橙微兮° 2022-08-05 13:08 184阅读 0赞

MVP -- Model View Presenter

MartinFowler 的 [ 这篇文章][Link 1] 将MVP分为 [SupervisingPresenter][] 和 [PassiveView][]

Android 中MVP 例子： [https://github.com/antoniolg/androidmvp][https_github.com_antoniolg_androidmvp]

先看一下项目的结构

![SouthEast][] ![SouthEast 1][]

可以看出每个功能模块包含 XXActivity，XXView （Interface），XXPresenter（interface），XXPresenterImp

LoginView接口，负责逻辑处理

public interface LoginView {
        public void showProgress();
    
        public void hideProgress();
    
        public void setUsernameError();
    
        public void setPasswordError();
    
        public void navigateToHome();
    }

LoginPresenter接口

public interface LoginPresenter {
        public void validateCredentials(String username, String password);
    }

LoginActivity，实现了LoginView接口，实现了对应的方法，内部包含一个Presenter作为成员变量，presenterImp调用响应的方法进行UI更新与同步

public class LoginActivity extends Activity implements LoginView, View.OnClickListener {
    
        private ProgressBar progressBar;
        private EditText username;
        private EditText password;
        private LoginPresenter presenter;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_login);
    
            progressBar = (ProgressBar) findViewById(R.id.progress);
            username = (EditText) findViewById(R.id.username);
            password = (EditText) findViewById(R.id.password);
            findViewById(R.id.button).setOnClickListener(this);
    
            presenter = new LoginPresenterImpl(this);
        }
    
        @Override public void showProgress() {
            progressBar.setVisibility(View.VISIBLE);
        }
    
        @Override public void hideProgress() {
            progressBar.setVisibility(View.GONE);
        }
    
        @Override public void setUsernameError() {
            username.setError(getString(R.string.username_error));
        }
    
        @Override public void setPasswordError() {
            password.setError(getString(R.string.password_error));
        }
    
        @Override public void navigateToHome() {
            startActivity(new Intent(this, MainActivity.class));
            finish();
        }
    
        @Override public void onClick(View v) {
            presenter.validateCredentials(username.getText().toString(), password.getText().toString());
        }
    }

LoginPresenterImp，实现了LoginPresenter

ublic class LoginPresenterImpl implements LoginPresenter, OnLoginFinishedListener {
    
        private LoginView loginView;
        private LoginInteractor loginInteractor;
    
        public LoginPresenterImpl(LoginView loginView) {
            this.loginView = loginView;
            this.loginInteractor = new LoginInteractorImpl();
        }
    
        @Override public void validateCredentials(String username, String password) {
            loginView.showProgress();
            loginInteractor.login(username, password, this);
        }
    
        @Override public void onUsernameError() {
            loginView.setUsernameError();
            loginView.hideProgress();
        }
    
        @Override public void onPasswordError() {
            loginView.setPasswordError();
            loginView.hideProgress();
        }
    
        @Override public void onSuccess() {
            loginView.navigateToHome();
        }
    }

整个项目架构中，将逻辑处理和UI同步更新从Activity中分离出来，代码更加简洁

对于MVP还不是太理解，还需要再多看例子啊

关于[MVP的改进][MVP] ：[博客][Link 2]

[Link 1]: http://martinfowler.com/eaaDev/ModelViewPresenter.html
[SupervisingPresenter]: http://martinfowler.com/eaaDev/SupervisingPresenter.html
[PassiveView]: http://martinfowler.com/eaaDev/PassiveScreen.html
[https_github.com_antoniolg_androidmvp]: https://github.com/antoniolg/androidmvp
[SouthEast]: https://img-blog.csdn.net/20150406235245964?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaHB1X3p5aA==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast
[SouthEast 1]: /images/20220805/b0e6bda2bc094a4c8f184cd27d591bb9.png
[MVP]: https://github.com/wongcain/MVP-Simple-Demo
[Link 2]: http://blog.cainwong.com/android-mvp-an-alternate-approach/