1.什么是MVP？ 简单理解：就是通过Presenter将View和Model解耦
M —>Model 包括：与数据相关都属于M层（例如：数据库、文件、网络、数据解析、数据保存......） V —>View 包括：在MVC中View只是一个单纯视图，但是在MVP中(例如：Activity、Fragment、布局) P —>Presenter 包括：调度，通过P层将我们的View层和Model层进行关联转换
2.MVP和设计模式有什么区别？ 举例说明：北京国贸三期（整体架构） --- MVP 国贸三期中 窗户设计、电梯设计、走廊设计 ...... 相当于设计模式 --- 针对具体的问题或者场景提出不同的解决方案。
3.MVP架构交互过程
简单MVP登录案例
public interface MainView {public void onLoginResult(String result);}复制代码
public class MainActivity extends AppCompatActivity implements MainView {private MainPresenter mainPresenter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);this.mainPresenter = new MainPresenter(this);}/*** 其实在Android当中，本身就是一个非常典型的MVC架构* 在Android MVC中* M代表：数据* C代表：activity或者Fragment* V代表：视图*///MVP适合大项目//MVP更加便于团队开发public void click(View v){this.mainPresenter.login("kpioneer","123456");}@Overridepublic void onLoginResult(String result) {Toast.makeText(this,result, Toast.LENGTH_LONG).show();}复制代码
/*** Created by Xionghu on /7/11.* Desc: M层(数据、网络)*/public class MainModel {public void login(String username, String pwd, final HttpUtils.OnHttpResultListener onHttpResultListener){HttpTask httpTask = new HttpTask(new HttpUtils.OnHttpResultListener() {@Overridepublic void onResult(String result) {//解析数据//更新UIonHttpResultListener.onResult(result);}});httpTask.execute(username,pwd,"");}}复制代码
public class MainPresenter {private MainView mainView;private MainModel mainModel;public MainPresenter(MainView mainView) {this.mainView = mainView;this.mainModel = new MainModel();}public void login(String userName, String pwd){this.mainModel.login(userName, pwd, new HttpUtils.OnHttpResultListener() {@Overridepublic void onResult(String result) {mainView.onLoginResult(result);}});}复制代码
5.分析简单MVP登录案例的问题？ 问题1： 假设Activty意外关闭，这个时候网络请求还在进行，当数据返回的时候，发现Activity(或者Fragment) 挂掉了将会造成内存泄漏。
解决办法：MainPresenter提供一个销毁mainView的方法问题2：项目开发当中Activity或者Fragment数量很庞大 Presenter相关类将会造成代码冗余。解决办法： 单独抽象出来(引出抽象类)抽象类设计MVP架构复制代码
抽象 AbsMvpPresenter
public abstract class AbsMvpPresenter<V extends IMvpView> {private V view;public V getView() {return view;}/*** 绑定* @param view*/public void attachView(V view) {this.view = view;}/*** 解决绑定*/public void detachView(){this.view =null;}}复制代码
public interface IMvpView {}复制代码
public class MainPresenter extends AbsMvpPresenter<MainView> {private MainModel mainModel;public MainPresenter() {this.mainModel = new MainModel();}public void login(String userName, String pwd){this.mainModel.login(userName, pwd, new HttpUtils.OnHttpResultListener() {@Overridepublic void onResult(String result) {if(getView()!=null){getView().onLoginResult(result);}}});}复制代码
}
public abstract class MvpActivity<V extends IMvpView, P extends AbsMvpPresenter<V>> extends Activity {private P presenter;private V view;@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);if (presenter == null) {this.presenter = bindPresenter();}if (view == null) {this.view = bindView();this.presenter.attachView(this.view);}}public P getPresenter() {return presenter;}public V getView() {return view;}public abstract P bindPresenter();public abstract V bindView();@Overrideprotected void onDestroy() {super.onDestroy();if (this.presenter != null) {this.presenter.detachView();}}}复制代码
public class MainActivity extends MvpActivity<MainView,MainPresenter> implements MainView {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}@Overridepublic MainPresenter bindPresenter() {return new MainPresenter();}@Overridepublic MainView bindView() {return this;}/*** 其实在Android当中，本身就是一个非常典型的MVC架构* 在Android MVC中* M代表：数据* C代表：activity或者Fragment* V代表：视图*///MVP适合大项目//MVP更加便于团队开发public void click(View v){getPresenter().login("kpioneer","123456");}@Overridepublic void onLoginResult(String result) {Toast.makeText(this,result, Toast.LENGTH_LONG).show();}@Overrideprotected void onDestroy() {super.onDestroy();}} 复制代码
问题三：
6.搭建MVP架构
public class MainPresenter extends MvpBasePresenter<MainView> {private MainModel mainModel;public MainPresenter(Context context) {super(context);this.mainModel = new MainModel();}public void login(String username, String pwd) {this.mainModel.login(username, pwd, new HttpUtils.OnHttpResultListener() {@Overridepublic void onResult(String result) {if(isAttachView()){getView().onLoginResult(result);}}});}}复制代码
问题：每一次在Presenter中调用方法都需要处理空（isAttachView()）判断 假设：50个Activity，20个Presenter，每一个Presenter里面有20个方法，做判断400次？
解决办法 ----- 动态代理模式每当调用这个方法的时候，我就要去监听复制代码
public interface MvpPresenter<V extends MvpView> {/*** 绑定视图* @param view*/public void attachView(V view);public void dettachView();}复制代码
public class MvpBasePresenter<V extends MvpView> implements MvpPresenter<V> {private WeakReference<Context> weakContext;private WeakReference<V> weakView;private V proxyView;public MvpBasePresenter(Context context) {this.weakContext = new WeakReference<Context>(context);}public Context getContext() {return weakContext.get();}public V getView() {return proxyView;}/*** 用于检测View是否为空对象** @return*/public boolean isAttachView() {if (this.weakView != null && this.weakView.get() != null) {return true;}return false;}@Overridepublic void attachView(V view) {this.weakView = new WeakReference<V>(view);MvpViewInvocationHandler invocationHandler = new MvpViewInvocationHandler(this.weakView.get());//在这里采用动态代理proxyView = (V) Proxy.newProxyInstance(view.getClass().getClassLoader(), view.getClass().getInterfaces(), invocationHandler);}@Overridepublic void dettachView() {if (weakView.get() != null) {this.weakView.clear();this.weakView = null;}}private class MvpViewInvocationHandler implements InvocationHandler {private MvpView mvpView;public MvpViewInvocationHandler(MvpView mvpView) {this.mvpView = mvpView;}@Overridepublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable {if (isAttachView()) {return method.invoke(mvpView, args);}return null;}}}复制代码
关键代码
public void attachView(V view) {this.weakView = new WeakReference<V>(view);MvpViewInvocationHandler invocationHandler = new MvpViewInvocationHandler(this.weakView.get());//在这里采用动态代理proxyView = (V) Proxy.newProxyInstance(view.getClass().getClassLoader(), view.getClass().getInterfaces(), invocationHandler);}private class MvpViewInvocationHandler implements InvocationHandler {private MvpView mvpView;public MvpViewInvocationHandler(MvpView mvpView) {this.mvpView = mvpView;}@Overridepublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable {if (isAttachView()) {return method.invoke(mvpView, args);}return null;}}复制代码
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