Android MVP进阶-项目实战

概述

现在比较热门的架构有MVP与MVVM，两者比较类似。

• 作为MVP衍生版的MVVM增加了响应式编程，它的缺点很明显。
• 依赖更多复杂的框架，增加了不确定性
• 数据绑定使得 Bug 很难被调试
• 对于过大的项目，数据绑定需要花费更多的内存
• XML页面增加了过多的业务逻辑

这几点都是我比较不喜欢的地方，所以我选择了MVP作为项目的架构。

切入正题：我们直接看代码吧：

项目结构

项目结构

使用第三方框架

• Retrofit
• RxJava
• Okhttp3

View基类

用于在Presenter中执行View层中的基本方法

public interface IBaseView {
    // 只做局部变量使用
    Context getActivity();
    Context getContext();
    void showProgressDialog(String msg);
    void showProgressDialog(String msg, boolean cancelable);
    void showProgressDialog();
    void dismissProgressDialog();
    void showToast(String msg);
    void showToast(int id);
    void onCompleted();
    void onError();
}

Presenter基类

绑定视图提供一些基础方法给View调用，也可以看成视图层通知Presenter我加载好了、我销毁了的意思。管理Retrofit的请求并简化RxJava写法。

public abstract class BasePresenter  {

    protected V mView;
    private CompositeSubscription mCompositeSubscription;

    // 绑定视图
    public BasePresenter(V v) {
        mView = v;
    }

    public void onResume() {}
    public void onStop() {}

    private void addSubscription(Subscription s) {
        if (mCompositeSubscription == null) {
            mCompositeSubscription = new CompositeSubscription();
        }
        mCompositeSubscription.add(s);
    }

    protected D addMainSubscription(Observable observable, Subscriber subscriber) {
        addSubscription(observable.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(subscriber));
        return null;
    }

    protected D addThreadSubscription(Observable observable, Subscriber subscriber) {
        addSubscription(observable.subscribeOn(Schedulers.io()).observeOn(Schedulers.io()).subscribe(subscriber));
        return null;
    }

    public void onDestroy() {
        if (mCompositeSubscription != null && mCompositeSubscription.hasSubscriptions()) {
            mCompositeSubscription.unsubscribe();
        }
    }

    public void unAttachView() {
        if (mView != null) {
            mView = null;
        }
    }
}

Activity基类

提供一些视图的方法并与Presenter绑定关联它们的生命周期，Activity销毁后Presenter不再执行任何逻辑。并实现一些View的基本方法供Presenter使用。

public abstract class BasicActivity 
 extends AppCompatActivity implements IBaseView,
View.OnClickListener {

    ...省略
    protected P mPresenter;

    @Override 
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPresenter = attachView();
        initView();

        getWindow().getDecorView().post(new Runnable() {@Override public void run() {
                onCreateView();
            }
        });
    }

    private void initView() {
        ...
    }

    /**
     * 绑定Presenter
     */
    protected abstract P attachView();

    @Override protected void onResume() {
        super.onResume();
        if (mPresenter != null) mPresenter.onResume();
    }

    @Override protected void onStop() {
        super.onStop();
        if (mPresenter != null) mPresenter.onStop();
    }

    @Override protected void onDestroy() {
        super.onDestroy();
        if (mPresenter != null) {
            mPresenter.onDestroy();
        }
        if (mPresenter != null) {
            mPresenter.unAttachView();
            mPresenter = null;
        }
    }
    ...省略

    /**
     * 尽量不去使用，只做预留功能
     */
    @Override public Context getActivity() {
        return this;
    }

    @Override public Context getContext() {
        return BaseApplication.getContext();
    }
}

Contract

负责约定view层和presenter层的接口，view和presenter实现相应接口，最终达到解耦的目的。

public interface HomeContract {
    interface View extends IBaseView {
        void onUserLoadCompleted(PhoneLocalBean bean);
        void onUserLoadError();
    }

    abstract class Presenter extends BasePresenter < View > {
        Presenter(View view) {
            super(view);
        }
        public abstract void queryWeather(String phone);
    }
}

Presenter
负责从model层获取数据、整理数据、行为处理等。处理后调用view显示数据。

public class HomePresenter extends HomeContract.Presenter {

    public HomePresenter(HomeContract.View view) {
        super(view);
    }

    @Override public void queryWeather(String phone) {
        Map  options = new HashMap<>();
        options.put("phone", phone);
        addMainSubscription(HttpManager.getInstance().sendRequest().queryWeather(options), new HttpResultCallBack () {

            @Override public void onResponse(PhoneLocalBean bean, int status) {
                if (bean != null) {
                    mView.onUserLoadCompleted(bean);
                } else {
                    mView.onUserLoadError();
                }
            }

            @Override public void onErr(String err, int status) {
                mView.showToast(err);
                mView.onUserLoadError();
            }
        });
    }
}

Model

Model中又分为Net获取数据和DB存取数据，我这里没有使用到数据库操作推荐大家使用GreenDAO。

public interface HttpService {
    @GET(GlobalVar.NetPorts.WEATHER)
    Observable> queryWeather(@QueryMap Map options);
}

视图

public class HomeActivity extends BasicActivity implements HomeContract.View {

    private EditText mPhoneEt;
    private TextView mAddressTv;

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

        mPhoneEt = (EditText) findViewById(R.id.main_phones_et);
        mAddressTv = (TextView) findViewById(R.id.main_address_tv);
        Button queryBt = (Button) findViewById(R.id.main_query_bt);
        queryBt.setOnClickListener(this);
    }

    @Override protected HomePresenter attachView() {
        return new HomePresenter(this);
    }

    @Override public void onClick(View v) {
        super.onClick(v);
        switch (v.getId()) {
        case R.id.main_query_bt:
            String phone = mPhoneEt.getText().toString().trim();
            if (TextUtils.isEmpty(phone)) return;

            showProgressDialog();
            mPresenter.queryWeather(phone);
            break;
        }
    }

    @Override public void onUserLoadCompleted(PhoneLocalBean bean) {
        dismissProgressDialog();
        mAddressTv.setText("归属地：" + bean.getCity());
    }

    @Override public void onUserLoadError() {
        dismissProgressDialog();
        mAddressTv.setText("获取失败");
    }
}

最后推荐一张图片，MVP之间的交互关系很好的体现出来

mvp示意图

github源码下载