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如何应对 Android 面试官 -> MVVM 实战一个新闻客户端 (中)

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站长
· 阅读数 38

前言

本章我们基于重构的方式进行一个 MVVM 的实战，我们将一个新闻列表的普通实现，一步一步的改造成 MVVM 的架构模式，一共分为上中下三个章节，本章继续上一章，开始中篇的讲解；

控件化

我们本章向控件化进一步迈进

BaseView 重构

我们上一章，将 TitleView 和 PictureTitleView 抽取了一个 BaseView 来抽取公共的 setData 逻辑，我们还可以继续精进一步；

我们现将我们上一章定义的接口 BaseView 重命名成 IBaseView

public interface IBaseView<DATA extends BaseViewModel> {

    void setData(DATA data);
}

然后我们定义一个 IBaseView 的实现类，BaseView

public abstract class BaseView extends LinearLayout implements IBaseView<BaseViewModel> {
    public BaseView(Context context) {
        super(context);
    }

    public BaseView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public BaseView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public BaseView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public void setData(BaseViewModel baseViewModel) {
        
    }
}

然后我们定义公共的 init 方法，方法中我们进行布局的加载，但是布局 id 我们无法从自身获取，需要通过 工厂方法 模式，提供一个抽象接口来从子类中获取布局 id；同时，通过 泛型 来接收 DataBinding 在 inflater 之后返回的 ViewDataBinding 对象，整体如下：

public abstract class BaseView<VIEW_BINDING extends ViewDataBinding> extends LinearLayout implements IBaseView<BaseViewModel> {

    protected VIEW_BINDING mBinding;
    
    private void init() {
        LayoutInflater layoutInflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mBinding = DataBindingUtil.inflate(layoutInflater, getLayoutId(), this, false);
        addView(mBinding.getRoot());
    }

    public abstract int getLayoutId();
}

通常，View 可能会需要一个点击事件，我们这里也提供一下

private void init() {
    LayoutInflater layoutInflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    mBinding = DataBindingUtil.inflate(layoutInflater, getLayoutId(), this, false);
    mBinding.getRoot().setOnClickListener(this::onRootClick);
    addView(mBinding.getRoot());
}

public abstract int getLayoutId();

public abstract void onRootClick(View view);

然后，我们来实现 setData 部分，这里我们将泛型的实现交给 BaseView

public abstract class BaseView<VIEW_BINDING extends ViewDataBinding, DATA extends BaseViewModel> extends LinearLayout implements IBaseView<DATA> {
    
}

然后，我们发现，当我们在 setData 中去 setViewModel 的时候，报错了，并没有 setViewModel 的接口，那么我们就需要进行剥离出来，交给子类实现；

如何应对 Android 面试官 -> MVVM 实战一个新闻客户端 (中)

public abstract class BaseView<VIEW_BINDING extends ViewDataBinding, DATA extends BaseViewModel> extends LinearLayout implements IBaseView<DATA> {
    
    @Override
    public void setData(DATA baseViewModel) {
        setDataToView(baseViewModel);
        mBinding.executePendingBindings();
    }
    
    
    public abstract void setDataToView(DATA data);
}

我们接下来重构 TitleView 和 PictureTitleView，来让它们继承 BaseView

public class TitleView extends BaseView<TitleViewBinding, TitleViewModel> {

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

    @Override
    public int getLayoutId() {
        return R.layout.title_view;
    }

    @Override
    public void onRootClick(View view) {

    }

    @Override
    public void setDataToView(TitleViewModel titleViewModel) {
        mBinding.setTitleViewModel(titleViewModel);
    }
}

PictureTitleView

public class PictureTitleView extends BaseView<PictureTitleViewBinding, PictureTitleViewModel> {

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

    @Override
    public int getLayoutId() {
        return R.layout.picture_title_view;
    }

    @Override
    public void onRootClick(View view) {

    }

    @Override
    public void setDataToView(PictureTitleViewModel pictureTitleViewModel) {
        mBinding.setPictureTitleViewModel(pictureTitleViewModel);
    }

    @BindingAdapter("loadImageUrl")
    public static void loadImageUrl(ImageView imageView, String imgUrl) {
        Glide.with(imageView.getContext())
                .load(imgUrl)
                .transition(withCrossFade())
                .into(imageView);
    }
}

可以看到，我们的 TitleView 和 PictureTitleView 也清爽了很多；到这里，对齐了我们在讲 MVx 的时候的 控件化 的重要性；

Model

我们接下来，终于可以向 MVVM 的架构来迈进了，我们先来看下我们的 Fragment，一开始我们把数据的加载直接放在了 Fragment 中，这其实并不合理，我们需要将数据的获取放到 model 层，我们来进行重构；

首先我们在 base 层定义下我们的 baseModel，创建一个 IBaseModelListener，用来将 model 获取的数据回调到 View

public interface IBaseModelListener<DATA> {
    void onLoadSuccess(DATA data);
    void onLoadFail(int errorCode, String errorMsg);
}

然后我们定义一个我们用来获取频道列表的 model

public class NewsChannelModel {

    private IBaseModelListener<List<NewsChannelsBean.ChannelList>> mListener;

    public NewsChannelModel(IBaseModelListener<List<NewsChannelsBean.ChannelList>> mListener) {
        this.mListener = mListener;
    }

    public void load() {
        TecentNetworkApi.getService(NewsApiInterface.class)
                .getNewsChannels()
                .compose(TecentNetworkApi.getInstance().applySchedulers(new BaseObserver<NewsChannelsBean>() {
                    @Override
                    public void onSuccess(NewsChannelsBean newsChannelsBean) {
                        mListener.onLoadSuccess(newsChannelsBean.showapiResBody.channelList);
                    }

                    @Override
                    public void onFailure(Throwable e) {
                        e.printStackTrace();
                        mListener.onLoadFail(400, e.getMessage());
                    }
                }));
    }
}

然后，我们在 Fragment 中调用这个 model 的 load 方法；

public class HeadlineNewsFragment extends Fragment implements IBaseModelListener<List<NewsChannelsBean.ChannelList>> {
    public HeadlineNewsFragmentAdapter adapter;
    private FragmentHomeBinding viewDataBinding;
    private NewsChannelModel model;
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        viewDataBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_home, container, false);
        adapter = new HeadlineNewsFragmentAdapter(getChildFragmentManager());
        viewDataBinding.tablayout.setTabMode(TabLayout.MODE_SCROLLABLE);
        viewDataBinding.viewpager.setAdapter(adapter);
        viewDataBinding.tablayout.setupWithViewPager(viewDataBinding.viewpager);
        viewDataBinding.viewpager.setOffscreenPageLimit(1);
        model = new NewsChannelModel(this);
        model.load();
        return viewDataBinding.getRoot();
    }

    @Override
    public void onLoadSuccess(List<NewsChannelsBean.ChannelList> channelLists) {
        if (adapter != null) {
            adapter.setChannels(channelLists);
        }
    }

    @Override
    public void onLoadFail(int errorCode, String errorMsg) {}
}

Fragment 也清爽了很多，我们接下来重构下 NewsListFragment，重构逻辑一样，我们封装一个 NewListModel

public class NewsListModel {

    private IBaseModelListener<ArrayList<BaseViewModel>> mListener;
    private int mPageNum;
    private String mChannelId;

    private String mChannelName;

    public NewsListModel(IBaseModelListener<ArrayList<BaseViewModel>> mListener, String channelId, String channelName) {
        this.mListener = mListener;
        this.mChannelId = channelId;
        this.mChannelName = channelName;
    }

    public void load() {
        TecentNetworkApi.getService(NewsApiInterface.class)
                .getNewsList(mChannelId,
                        mChannelName, String.valueOf(mPageNum))
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .flatMap(new Function<NewsListBean, ObservableSource<ArrayList<BaseViewModel>>>() {
                    @Override
                    public ObservableSource<ArrayList<BaseViewModel>> apply(NewsListBean newsChannelsBean) throws Exception {
                        ArrayList<BaseViewModel> viewModels = new ArrayList<>();
                        for (NewsListBean.Contentlist contentlist : newsChannelsBean.showapiResBody.pagebean.contentlist) {
                            if (contentlist.imageurls != null && contentlist.imageurls.size() > 0) {
                                PictureTitleViewModel pictureTitleViewModel = new PictureTitleViewModel();
                                pictureTitleViewModel.imgUrl = contentlist.imageurls.get(0).url;
                                pictureTitleViewModel.title = contentlist.title;
                                pictureTitleViewModel.jumpUrl = contentlist.link;
                                viewModels.add(pictureTitleViewModel);
                            } else {
                                TitleViewModel titleViewModel = new TitleViewModel();
                                titleViewModel.title = contentlist.title;
                                titleViewModel.jumpUrl = contentlist.link;
                                viewModels.add(titleViewModel);
                            }
                        }
                        return Observable.just(viewModels);
                    }
                })
                .subscribe(new Consumer<ArrayList<BaseViewModel>>() {
                    @Override
                    public void accept(ArrayList<BaseViewModel> baseViewModels) throws Exception {
                        mPageNum++;
                        mListener.onLoadSuccess(baseViewModels);
                    }
                });
    }

    public void refresh() {
        mPageNum = 1;
        load();
    }
}

然后 NewListFragment 重构如下：

public class NewsListFragment extends Fragment implements IBaseModelListener<ArrayList<BaseViewModel>> {
    private NewsListRecyclerViewAdapter mAdapter;
    private FragmentNewsBinding viewDataBinding;
    private NewsListModel mNewsListModel;
    protected final static String BUNDLE_KEY_PARAM_CHANNEL_ID = "bundle_key_param_channel_id";
    protected final static String BUNDLE_KEY_PARAM_CHANNEL_NAME = "bundle_key_param_channel_name";

    public static NewsListFragment newInstance(String channelId, String channelName) {
        NewsListFragment fragment = new NewsListFragment();
        Bundle bundle = new Bundle();
        bundle.putString(BUNDLE_KEY_PARAM_CHANNEL_ID, channelId);
        bundle.putString(BUNDLE_KEY_PARAM_CHANNEL_NAME, channelName);
        fragment.setArguments(bundle);
        return fragment;
    }

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        viewDataBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_news, container, false);
        mAdapter = new NewsListRecyclerViewAdapter(getContext());
        viewDataBinding.listview.setHasFixedSize(true);
        viewDataBinding.listview.setLayoutManager(new LinearLayoutManager(getContext()));
        viewDataBinding.listview.setAdapter(mAdapter);
        mNewsListModel = new NewsListModel(this, getArguments().getString(BUNDLE_KEY_PARAM_CHANNEL_ID),
                getArguments().getString(BUNDLE_KEY_PARAM_CHANNEL_NAME));
        mNewsListModel.load();
        viewDataBinding.refreshLayout.setOnRefreshListener(new OnRefreshListener() {
            @Override
            public void onRefresh(@NonNull RefreshLayout refreshLayout) {
               mNewsListModel.refresh();
            }
        });
        viewDataBinding.refreshLayout.setOnLoadMoreListener(new OnLoadMoreListener() {
            @Override
            public void onLoadMore(@NonNull RefreshLayout refreshLayout) {
                mNewsListModel.load();
            }
        });
        return viewDataBinding.getRoot();
    }

    @Override
    public void onLoadSuccess(ArrayList<BaseViewModel> baseViewModels) {
        contentList.addAll(baseViewModels);
        mAdapter.setData(contentList);
        viewDataBinding.refreshLayout.finishRefresh();
        viewDataBinding.refreshLayout.finishLoadMore();
    }

    @Override
    public void onLoadFail(int errorCode, String errorMsg) {

    }
}

我们这个页面的数据加载，涉及到了分页的逻辑，我们需要将回调的结果带上分页的结果，要告知 View 是加载的哪一页，我们需要一个分页结果；

public class PageResult {

    private boolean isFirstPage;
    private boolean isEmpty;
    private boolean hasNextPage;

    public PageResult(boolean isFirstPage, boolean isEmpty, boolean hasNextPage) {
        this.isFirstPage = isFirstPage;
        this.isEmpty = isEmpty;
        this.hasNextPage = hasNextPage;
    }
}

然后，我们修改回调结果的 Listener，这个接口是公共的，也就是说，有的需要分页结果，有的不需要分页结果，那么就需要一个可变参数；

public interface IBaseModelListener<DATA> {

    void onLoadSuccess(DATA data, PageResult... pageResults);
    void onLoadFail(int errorCode, String errorMsg);
}

然后，NewsListModel 的回调带上这个 PageResult；

mListener.onLoadSuccess(baseViewModels,
        new PageResult(mPageNum == 1, baseViewModels.isEmpty(), baseViewModels.size() >= 10));

onLoadSuccess 的回调改造如下：

@Override
public void onLoadSuccess(ArrayList<BaseViewModel> baseViewModels, PageResult... pageResults) {
    if (pageResults != null && pageResults.length > 0 && pageResults[0].isFirstPage) {
        contentList.clear();
    }
    contentList.addAll(baseViewModels);
    mAdapter.setData(contentList);
    viewDataBinding.refreshLayout.finishRefresh();
    viewDataBinding.refreshLayout.finishLoadMore();
}

到这的时候，我们的 model 层就抽离出来了，可能看到这的时候，好多人就疑问了，你这也没使用 Jetpack 的 ViewModel 和 LiveData 呀，别着急，我们精彩的还在后面；

BaseModel

可以看到，NewChannelModel 和 NewListModel 中都有 IBaseModelListener，这个是可以抽取到 base 层的，所以我们可以创建一个 BaseMvvmModel 来抽取它；

public abstract class BaseMvvmModel {
    
    protected WeakReference<IBaseModelListener> mReferenceIBaseModeListener;
    
    public void register(IBaseModelListener listener) {
        if (listener != null) {
            mReferenceIBaseModeListener = new WeakReference<>(listener);
        }
    }
}

然后，NewListModel 和 NewsChannelModel 分别继承 BaseMvvmModel，同时移除子类 model 中的 IBaseModelListener 的声明；

public class NewsListModel extends BaseMvvmModel {

    private int mPageNum;
    private final String mChannelId;

    private final String mChannelName;

    public NewsListModel(String channelId, String channelName) {
        this.mChannelId = channelId;
        this.mChannelName = channelName;
    }

    public void load() {
        TecentNetworkApi.getService(NewsApiInterface.class)
                .getNewsList(mChannelId,
                        mChannelName, String.valueOf(mPageNum))
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .flatMap(new Function<NewsListBean, ObservableSource<ArrayList<BaseViewModel>>>() {
                    @Override
                    public ObservableSource<ArrayList<BaseViewModel>> apply(NewsListBean newsChannelsBean) throws Exception {
                        ArrayList<BaseViewModel> viewModels = new ArrayList<>();
                        for (NewsListBean.Contentlist contentlist : newsChannelsBean.showapiResBody.pagebean.contentlist) {
                            if (contentlist.imageurls != null && contentlist.imageurls.size() > 0) {
                                PictureTitleViewModel pictureTitleViewModel = new PictureTitleViewModel();
                                pictureTitleViewModel.imgUrl = contentlist.imageurls.get(0).url;
                                pictureTitleViewModel.title = contentlist.title;
                                pictureTitleViewModel.jumpUrl = contentlist.link;
                                viewModels.add(pictureTitleViewModel);
                            } else {
                                TitleViewModel titleViewModel = new TitleViewModel();
                                titleViewModel.title = contentlist.title;
                                titleViewModel.jumpUrl = contentlist.link;
                                viewModels.add(titleViewModel);
                            }
                        }
                        return Observable.just(viewModels);
                    }
                })
                .subscribe(new Consumer<ArrayList<BaseViewModel>>() {
                    @Override
                    public void accept(ArrayList<BaseViewModel> baseViewModels) throws Exception {
                        mPageNum++;
                        mReferenceIBaseModeListener.get().onLoadSuccess(baseViewModels,
                                new PageResult(mPageNum == 1, baseViewModels.isEmpty(), baseViewModels.size() >= 10));
                    }
                });
    }

    public void refresh() {
        mPageNum = 1;
        load();
    }
}

NewsChannelModel 重构如下：

public class NewsChannelModel extends BaseMvvmModel {

    public NewsChannelModel() {
    }

    public void load() {
        TecentNetworkApi.getService(NewsApiInterface.class)
                .getNewsChannels()
                .compose(TecentNetworkApi.getInstance().applySchedulers(new BaseObserver<NewsChannelsBean>() {
                    @Override
                    public void onSuccess(NewsChannelsBean newsChannelsBean) {
                        mReferenceIBaseModeListener.get().onLoadSuccess(newsChannelsBean.showapiResBody.channelList);
                    }

                    @Override
                    public void onFailure(Throwable e) {
                        e.printStackTrace();
                        mReferenceIBaseModeListener.get().onLoadFail(400, e.getMessage());
                    }
                }));
    }
}

然后对应的 Fragment 也需要重构下：

mNewsListModel = new NewsListModel(getArguments().getString(BUNDLE_KEY_PARAM_CHANNEL_ID),
        getArguments().getString(BUNDLE_KEY_PARAM_CHANNEL_NAME));
mNewsListModel.register(this);

model = new NewsChannelModel();
model.register(this);

然后，我们的 page 其实也可以抽取到 base 层，通过可变参数的形式来决定分页的内容以及是否要分页，所以 BaseMvvmModel 继续重构；

public abstract class BaseMvvmModel {

    protected WeakReference<IBaseModelListener> mReferenceIBaseModeListener;
    protected boolean mIsPaging;
    protected final int INIT_PAGE_NUMBER;

    public BaseMvvmModel(boolean isPaging, int... initPageNumber) {
        if (isPaging && initPageNumber != null && initPageNumber.length > 0) {
            INIT_PAGE_NUMBER = initPageNumber[0];
        } else {
            INIT_PAGE_NUMBER = -1;
        }
    }

    public void register(IBaseModelListener listener) {
        if (listener != null) {
            mReferenceIBaseModeListener = new WeakReference<>(listener);
        }
    }
}

子类实现中，也需要重构下

NewsChannelModel 的构造方法重构如下：

public NewsChannelModel() {
    super(false);
}

NewsListModel 的构造方法重构如下：

public NewsListModel(String channelId, String channelName) {
    super(true, 1);
    this.mChannelId = channelId;
    this.mChannelName = channelName;
}

到这里的时候，有人可能会问，INIT_PAGE_NUMBER 没有用到呀，定义它做什么？别急，它来了，我们其实也可以把 NewListModel 中的 refresh 和 load 提取到 base 层；

public abstract class BaseMvvmModel {

    public void refresh() {
        mPageNum = INIT_PAGE_NUMBER;
        load();
    }

    public abstract void load();
}

这样，我们定义的 INIT_PAGE_NUMBER 是不是就使用到了；然后我们还可以给 refresh 加上多次加载控制，如果正在加载中则不触发二次请求，所以需要我们定义一个变量来控制是否正在加载，同时我们来区分下加载下一页和加载；

public abstract class BaseMvvmModel {
    protected boolean isLoading;
    
    public void refresh() {
        if (!isLoading) {
            if (mIsPaging) {
                mPageNum = INIT_PAGE_NUMBER;
            }
            isLoading = true;
            load();
        }
    }

    public void loadNextPage() {
        if (!isLoading) {
            isLoading = true;
            load();
        }
    }
}

另外，我们在子类 model 中分别操作了 BaseMvvmModel 中的 mPageNum 和 mReferenceIBaseModeListener 这两个的操作也是需要抽取到 base 层的，我们来继续重构；

public abstract class BaseMvvmModel<RESULT_DATA> {
    
    //
    protected void notifyResultToListener(RESULT_DATA data) {
        IBaseModelListener listener = mReferenceIBaseModeListener.get();
        if (listener != null) {
            if (mIsPaging) {
                listener.onLoadSuccess(this, data, new PageResult(mPageNum == INIT_PAGE_NUMBER, data == null?true: ((List)data).isEmpty(), ((List)data).size() > 10));
            } else {
                listener.onLoadSuccess(this, data);
            }
        }

        if (mIsPaging) {
            if (data != null && ((List)data).size() > 0) {
                mPageNum ++;
            }
        }
        isLoading = false;
    }
    
   
    protected void loadFail(int errorCode, String errorMsg) {
        IBaseModelListener listener = mReferenceIBaseModeListener.get();
        if (listener != null) {
            listener.onLoadFail(errorCode, errorMsg);
        }
        isLoading = false;
    }
}

然后子类 model 中直接调用对应的 notifyResultToListener 和 loadFail

NewsListModel

subscribe(new Consumer<ArrayList<BaseViewModel>>() {
    @Override
    public void accept(ArrayList<BaseViewModel> baseViewModels) throws Exception {
        notifyResultToListener(baseViewModels);
    }
});

NewsChannelModel

.compose(TecentNetworkApi.getInstance().applySchedulers(new BaseObserver<NewsChannelsBean>() {
    @Override
    public void onSuccess(NewsChannelsBean newsChannelsBean) {
        notifyResultToListener(newsChannelsBean.showapiResBody.channelList);
    }

    @Override
    public void onFailure(Throwable e) {
        e.printStackTrace();
        loadFail(404, e.getMessage());
    }
}));

数据缓存

如果我们在无网的情况下打开 app，通常会展示一片空白，体验很不好，所以，就需要我们提前将数据缓存下来，当用户无网打开的时候，不至于显示一片白；

首先，我们来提供一个 CacheData；

public class BaseCachedData<DATA> {

    public long updateTimeInMills;
    public DATA data;
}

然后我们需要对 BaseMvvmModel 进行重构，增加缓存逻辑；

public abstract class BaseMvvmModel<NETWORK_DATA, RESULT_DATA> {

    private String mCachedPreferenceKey;
    private BaseCachedData<NETWORK_DATA> mData;

    public BaseMvvmModel(boolean isPaging, String cachedPreferenceKey, int... initPageNumber) {
        if (isPaging && initPageNumber != null && initPageNumber.length > 0) {
            INIT_PAGE_NUMBER = initPageNumber[0];
        } else {
            INIT_PAGE_NUMBER = -1;
        }
        // 增加缓存key
        this.mCachedPreferenceKey = cachedPreferenceKey;
    }

    protected void notifyResultToListener(NETWORK_DATA networkData, RESULT_DATA data) {
        IBaseModelListener listener = mReferenceIBaseModeListener.get();
        if (listener != null) {
            if (mIsPaging) {
                listener.onLoadSuccess(this, data, new PageResult(mPageNum == INIT_PAGE_NUMBER, data == null ? true : ((List) data).isEmpty(), ((List) data).size() > 10));
            } else {
                listener.onLoadSuccess(this, data);
            }
        }
        // 增加缓存逻辑，将网络数据缓存到本地
        if (mIsPaging) {
            if (mCachedPreferenceKey != null && mPageNum == INIT_PAGE_NUMBER) {
                saveDataToPreference(networkData);
            }
        } else {
            if (mCachedPreferenceKey != null) {
                saveDataToPreference(networkData);
            }
        }

        if (mIsPaging) {
            if (data != null && ((List) data).size() > 0) {
                mPageNum++;
            }
        }
    }

    private void saveDataToPreference(NETWORK_DATA networkData) {
        if (networkData != null) {
            BaseCachedData<NETWORK_DATA> baseCachedData = new BaseCachedData<>();
            baseCachedData.data = networkData;
            baseCachedData.updateTimeInMills = System.currentTimeMillis();
            // 这里可以调换成自己的 spUtils
            BasicDataPreferenceUtil.getInstance().setString(mCachedPreferenceKey, new Gson().toJson(baseCachedData));
        }
    }
}

同时 NewsChannelModel 和 NewsListModel 的构造方法以及 load 实现也需要重构下，增加需要缓存的数据的传入；

public class NewsChannelModel extends BaseMvvmModel<NewsChannelsBean, List<NewsChannelsBean.ChannelList>> {

    public NewsChannelModel() {
        super(false, "NEWS_CHANNEL_PREF_KEY");
    }

    @Override
    public void load() {
        TecentNetworkApi.getService(NewsApiInterface.class)
                .getNewsChannels()
                .compose(TecentNetworkApi.getInstance().applySchedulers(new BaseObserver<NewsChannelsBean>() {
                    @Override
                    public void onSuccess(NewsChannelsBean newsChannelsBean) {
                        notifyResultToListener(newsChannelsBean, newsChannelsBean.showapiResBody.channelList);
                    }

                    @Override
                    public void onFailure(Throwable e) {
                        e.printStackTrace();
                        mReferenceIBaseModeListener.get().onLoadFail(400, e.getMessage());
                    }
                }));
    }
}

NewsListModel 重构如下：

public class NewsListModel extends BaseMvvmModel<NewsListBean, ArrayList<BaseViewModel>> {

    private final String mChannelId;
    private final String mChannelName;
    private NewsListBean mNewsListBean;

    public NewsListModel(String channelId, String channelName) {
        super(true, channelId + channelName + "pref_key", 1);
        this.mChannelId = channelId;
        this.mChannelName = channelName;
    }

    @Override
    public void load() {
        TecentNetworkApi.getService(NewsApiInterface.class)
                .getNewsList(mChannelId,
                        mChannelName, String.valueOf(mPageNum))
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .flatMap(new Function<NewsListBean, ObservableSource<ArrayList<BaseViewModel>>>() {
                    @Override
                    public ObservableSource<ArrayList<BaseViewModel>> apply(NewsListBean newsChannelsBean) throws Exception {
                        ArrayList<BaseViewModel> viewModels = new ArrayList<>();
                        NewsListModel.this.mNewsListBean = newsChannelsBean;
                        for (NewsListBean.Contentlist contentlist : newsChannelsBean.showapiResBody.pagebean.contentlist) {
                            if (contentlist.imageurls != null && contentlist.imageurls.size() > 0) {
                                PictureTitleViewModel pictureTitleViewModel = new PictureTitleViewModel();
                                pictureTitleViewModel.imgUrl = contentlist.imageurls.get(0).url;
                                pictureTitleViewModel.title = contentlist.title;
                                pictureTitleViewModel.jumpUrl = contentlist.link;
                                viewModels.add(pictureTitleViewModel);
                            } else {
                                TitleViewModel titleViewModel = new TitleViewModel();
                                titleViewModel.title = contentlist.title;
                                titleViewModel.jumpUrl = contentlist.link;
                                viewModels.add(titleViewModel);
                            }
                        }
                        return Observable.just(viewModels);
                    }
                })
                .subscribe(new Consumer<ArrayList<BaseViewModel>>() {
                    @Override
                    public void accept(ArrayList<BaseViewModel> baseViewModels) throws Exception {
                        notifyResultToListener(NewsListModel.this.mNewsListBean, baseViewModels);
                    }
                });
    }
}

OK，运行可以看到，数据已经存到了 SP 中；

好了，中篇文章就讲解到这里吧；

下一章预告

MVVM 实战一个新闻客户端 (下)

欢迎三连

来都来了，点个关注点个赞吧，你的支持是我前进的最大动力

转载自:https://juejin.cn/post/7383341578025992204
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