極簡(jiǎn)的MVP設(shè)計(jì)模式配合UI框架

MVP可以實(shí)現(xiàn)視圖和數(shù)據(jù)的解耦

image

如圖所示 MVP使M與V分離 實(shí)現(xiàn)了解耦

定義BaseView 所有視圖的通用接口(activity fragment)

public interface BaseView {

    /**
     * 初始化數(shù)據(jù)
     */
    void loadData();

    /**
     * 更新View的狀態(tài)
     * @param state
     */
    void updateState(int state);
}

updateState整個(gè)方法是由我們來(lái)根據(jù)網(wǎng)絡(luò)返回的數(shù)據(jù)或者來(lái)判斷整個(gè)View的狀態(tài),定義了三個(gè)狀態(tài)值,由此來(lái)展示loading頁(yè)面 或者 error的頁(yè)面

    //加載狀態(tài)
    public static final int STATUS_LOADING = 100;
    //成功狀態(tài)
    public static final int STATUS_SUCCESS = 101;
    //失敗狀態(tài)
    public static final int STATUS_ERROR = 102;

接著去定義通用的接口BaseViewImpl

public interface BaseViewImpl<D> extends BaseView{
    
    void attachPre();

    void showData(List<D> list);
}

attachPre 由View來(lái)關(guān)聯(lián)相應(yīng)的Presenter 可以在定義的BaseActivity里調(diào)用綁定Presenter

BasePresenter

public interface BasePresenter<V> {
    /**
     * 綁定View
     * @param view
     */
    void attachView(V view);

    /**
     * 解綁View
     */
    void detachView();
}

BasePresenter的實(shí)現(xiàn)類 基類

public abstract class BasePresenterImpl<V extends BaseView> implements BasePresenter<V>{

    public Context mContext;
    
    public V mBaseView;

    private CompositeSubscription mCompositeSubscription;

    public BasePresenterImpl(Context context){
        mContext = context;
    }

    @Override
    public void attachView(V view) {
        mBaseView = view;
    }

    @Override
    public void detachView() {
        this.mBaseView = null;
        onUnsubscribe(); //解綁
    }

    /**
     * 加載數(shù)據(jù)
     */
    public abstract void loadData();

    //RXjava取消注冊(cè)谐宙，以避免內(nèi)存泄露
    public void onUnsubscribe() {
        if (mCompositeSubscription != null && mCompositeSubscription.hasSubscriptions()) {
            mCompositeSubscription.unsubscribe();
        }
    }

    public void addSubscription(Observable observable, Subscriber subscriber) {
        if (mCompositeSubscription == null) {
            mCompositeSubscription = new CompositeSubscription();
        }
        mCompositeSubscription.add(subscriber);
    }
}

在BasePresenterImpl里綁定View ,由此子類可以根據(jù)View來(lái)更新?tīng)顟B(tài)

MVP就是基類的實(shí)現(xiàn)就是這么簡(jiǎn)單,現(xiàn)在來(lái)創(chuàng)建activity來(lái)試試手, 首先創(chuàng)建一個(gè)BaseActivity,抽取一些公共的代碼

public abstract class BaseActivity<T extends BasePresenter,D> extends AppCompatActivity implements BaseViewImpl<D>{
    
    public T mPresenter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        /**
         * 綁定Presenter
         */
        attachPre();
        View view = initView(LayoutInflater.from(this));
        setContentView(view);
        ButterKnife.bind(this);
        findView(view);
        loadData();
    }

    protected abstract View initView(LayoutInflater from);

    public abstract void findView(View view);

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(mPresenter != null)
            mPresenter.detachView();
        ButterKnife.unbind(this);
    }

    /**
     * error的統(tǒng)一處理
     * @param error
     */
    public void error(Throwable error){
        if(error instanceof NetworkErrorException){
            Toast.makeText(this,"網(wǎng)絡(luò)錯(cuò)誤", Toast.LENGTH_SHORT).show();
        }
    }

}

創(chuàng)建HomeActivity去訪問(wèn)網(wǎng)絡(luò)以及加載數(shù)據(jù)

public class HomeActivity extends BaseActivity<HomePresenter, NewsList.NewsEntity> {

    @Bind(R.id.recy)
    RecyclerView mRecy;
    private NewsListAdapter mNewsListAdapter;
    private LoadStuatus mLoadStuatus;

    @Override
    public View initView(LayoutInflater inflater) {
        /**
         * UI框架
         */
        mLoadStuatus = new LoadStuatus(this);
        /**
         * 實(shí)現(xiàn)成功頁(yè)面的View
         */
        mLoadStuatus.addSuccessView(inflater.inflate(R.layout.activity_home, null));
        /**
         * 綁定BaseView來(lái)實(shí)現(xiàn)頁(yè)面點(diǎn)擊加載
         */
        mLoadStuatus.bindView(this);
        return mLoadStuatus;
    }

    @Override
    public void findView(View view) {
        mRecy.setLayoutManager(new LinearLayoutManager(this));
        mNewsListAdapter = new NewsListAdapter(this);
        mRecy.setAdapter(mNewsListAdapter);
    }

    @Override
    public void attachPre() {
        mPresenter = new HomePresenter(this);
        mPresenter.attachView(this);
    }

    @Override
    public void showData(List<NewsList.NewsEntity> list) {
        mNewsListAdapter.flush(list);
    }

    @Override
    public void loadData() {
        mPresenter.loadData();
    }

    /**
     * 更新頁(yè)面
     */
    @Override
    public void updateState(int state) {
        mLoadStuatus.updateView(state);
    }
}

這里的loadStuatus是一個(gè)幀布局用來(lái)存放我們的三個(gè)頁(yè)面

errorPage,LoadPage,SuccessPage都是根據(jù)P層的回調(diào)來(lái)實(shí)現(xiàn)

在來(lái)看一下P層的實(shí)現(xiàn)

public class HomePresenter extends BasePresenterImpl<HomeActivity>{

    public HomePresenter(Context context) {
        super(context);
    }

    @Override
    public void loadData() {
        Subscription subscribe = RetrofitUtils.getinstance(mContext).buildNews().getNews()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(bean -> mBaseView.showData(bean.getNews()), //onNext() 去更新頁(yè)面
                        error -> {
                            mBaseView.error(error); // 請(qǐng)求網(wǎng)絡(luò)失敗 在BaseActivity定義了公共的處理方法
                            mBaseView.updateState(LoadStuatus.STATUS_ERROR); //更新頁(yè)面 顯示失敗的頁(yè)面
                        },
                        () -> mBaseView.updateState(LoadStuatus.STATUS_SUCCESS));// onComplete 完成頁(yè)面更新,顯示成功的頁(yè)面
        addSubscription(subscribe);
    }
}

P層很簡(jiǎn)單 就是訪問(wèn)網(wǎng)絡(luò) 當(dāng)請(qǐng)求

接下來(lái)看一下我們的UI框架 定義了統(tǒng)一處理頁(yè)面狀態(tài)的狀態(tài)碼以及如何去正確的顯示頁(yè)面

public class LoadStuatus extends FrameLayout {
    private static final String TAG = "TAG";
    BaseView nView;
    @Bind(R.id.error)
    View mErrorView;
    @Bind(R.id.loading)
    View mLoadingView;

    View successView;
    //加載狀態(tài)
    public static final int STATUS_LOADING = 100;
    //成功狀態(tài)
    public static final int STATUS_SUCCESS = 101;
    //失敗狀態(tài)
    public static final int STATUS_ERROR = 102;

    public LoadStuatus(Context context) {
        this(context, null);
    }

    public LoadStuatus(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public LoadStuatus(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public void addSuccessView(View view){
        successView = view;
        addView(successView);
        successView.setVisibility(GONE);
    }
    public void bindView(BaseView view) {
        this.nView = view;
        mErrorView.setOnClickListener(v -> {
            if(nView == null)
                throw new NoBindViewException("沒(méi)有綁定View");
            nView.loadData();
        });
    }

    public void init() {
        View.inflate(getContext(), R.layout.status, this);
        ButterKnife.bind(this);
    }

    public void updateView(int currentStatus) {
        switch (currentStatus) {
            case STATUS_ERROR:
                successView.setVisibility(GONE);
                mErrorView.setVisibility(VISIBLE);
                mLoadingView.setVisibility(GONE);
                break;
            case STATUS_LOADING:
                successView.setVisibility(GONE);
                mErrorView.setVisibility(GONE);
                mLoadingView.setVisibility(VISIBLE);
                break;
            case STATUS_SUCCESS:
                successView.setVisibility(VISIBLE);
                mErrorView.setVisibility(GONE);
                mLoadingView.setVisibility(GONE);
                break;
        }
    }

    public class NoBindViewException extends RuntimeException{
        public NoBindViewException(String info){
            super(info);
        }
    }
}

github地址: 點(diǎn)此進(jìn)入