BRVAH的BaseRecyclerViewAdapterHelper与MVVM模式优雅结合，Recyclerview如何在Databinding中快捷、方便地使用（二）

BRVAH的BaseRecyclerViewAdapterHelper与MVVM模式优雅结合（其一）

BRVAH的BaseRecyclerViewAdapterHelper与MVVM模式优雅结合（其三）

接上一章内容，如果大家没有看过第一章的话，请先看第一章。点上面链接就能跳转。

头部和脚部

public class HeadFootViewModel extends BaseBindingViewModel<SimpleData> {@Overrideprotected Map<Integer, CSBravhItemBinding> getItemBinding() {Map<Integer, CSBravhItemBinding> mp = new HashMap<>();mp.put(0, new CSBravhItemBinding(com.caesar.brvahbinding.BR.bean, R.layout.item_simple));return mp;}@Override//这个回调是头部的item的绑定数据,也支持绑定多个数据事件public ArrayList<CSBravhItemBinding> getHeadBinding() {ArrayList<CSBravhItemBinding> heads = new ArrayList<>();heads.add(new CSBravhItemBinding(BR.data, R.layout.layout_head_one, new HeadOneData(), BR.action, new brvah()));heads.add(new CSBravhItemBinding(BR.data, R.layout.layout_head_two, new HeadTwoData()));return heads;}@Override//这个回调是脚部的item的绑定数据,也支持绑定多个数据事件public ArrayList<CSBravhItemBinding> getFootBinding() {ArrayList<CSBravhItemBinding> foots = new ArrayList<>();foots.add(new CSBravhItemBinding(BR.data, R.layout.layout_foot_one, new FootOneData()));foots.add(new CSBravhItemBinding(BR.data, R.layout.layout_foot_two, new FootTwoData()));return foots;}@Overridepublic void load() {load(CreateData.getSimpleData());}@Overridepublic RecyclerView.ItemDecoration onitemDecoration() {return new NormalLineTopHeadDecoration(30, true);}//某个头部绑定的事件,告诉大家可以这样调用public class brvah implements CSAction0 {@Overridepublic void call() {bindingAdapter.removeAllHeaderView();}}
}

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto">
。。。<androidx.recyclerview.widget.RecyclerViewandroid:layout_width="match_parent"android:layout_height="match_parent"app:cs_brvah_Decoration="@{vm.itemDecoration}"app:cs_brvah_adapter="@{vm.bindingAdapter}"app:cs_brvah_footBinding="@{vm.footBinding}"app:cs_brvah_headBinding="@{vm.headBinding}" /></LinearLayout>
</layout>

先看布局文件，很简单，app:cs_brvah_footBinding="@{vm.footBinding}" app:cs_brvah_headBinding="@{vm.headBinding}"这2个方法，分别绑定了头部和脚部。接着，大家看HeadFootViewModel这个类，其中getHeadBinding（）这个回调，是绑定头部的，跟普通的item绑定很像，只是少了个itemType，里面传布局跟data，也可以绑定其他的事件。同理脚部布局数据是getFootBinding（）这个回调。是不是很简单。

空布局和下拉刷新

  <androidx.swiperefreshlayout.widget.SwipeRefreshLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"app:OnRefreshListener="@{vm.refreshListener}"app:refreshing="@{vm.isRefreshing}"><androidx.recyclerview.widget.RecyclerViewandroid:layout_width="match_parent"android:layout_height="match_parent"app:cs_brvah_Decoration="@{vm.itemDecoration}"app:cs_brvah_adapter="@{vm.bindingAdapter}"app:cs_brvah_emptyClickListener="@{vm.emptyOnClickListener}"app:cs_brvah_emptyResId="@{vm.emptyResId}" /></androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

public class EmptyRefrshViewModel extends BaseBindingViewModel<SimpleData> {private int countD;@Overrideprotected Map<Integer, CSBravhItemBinding> getItemBinding() {Map<Integer, CSBravhItemBinding> mp = new HashMap<>();mp.put(0, new CSBravhItemBinding(com.caesar.brvahbinding.BR.bean, R.layout.item_simple));return mp;}@Override//里面模拟网络请求时,出现的情况,正常返回,数据为空,请求错误.public void load() {++countD;if (countD % 3 == 0) {load(CreateData.getSimpleData());} else if (countD % 3 == 1) {load(getEmptyData());} else if (countD % 3 == 2) {load(getErrorData());}}//模拟数据返回为空public static Flowable<List<SimpleData>> getEmptyData() {CSLog.Print("调用加载空布局");return Flowable.create(new FlowableOnSubscribe<List<SimpleData>>() {@Overridepublic void subscribe(FlowableEmitter<List<SimpleData>> emitter) throws Exception {ArrayList<SimpleData> data = new ArrayList<>();emitter.onNext(data);emitter.onComplete();}}, BackpressureStrategy.BUFFER).delay(3, TimeUnit.SECONDS);}//模拟网络请求出错public static Flowable<List<SimpleData>> getErrorData() {CSLog.Print("调用加载错误");return Flowable.create(new FlowableOnSubscribe<List<SimpleData>>() {@Overridepublic void subscribe(FlowableEmitter<List<SimpleData>> emitter) throws Exception {emitter.onError(null);}}, BackpressureStrategy.BUFFER).delay(1, TimeUnit.SECONDS);}//清空数据的点击事件,这边因为我的baseAdapter里面,对items做过监听,可以看CSBindingListChangedCallBack这个类,所以,当items的数据发生//改变时,绑定的适配器会自动刷新,所以,如果你是使用自己的适配器的话(下面会讲),别忘记刷新适配器public void cliear(View view) {items.clear();}@Overridepublic RecyclerView.ItemDecoration onitemDecoration() {return new NormalLineDecoration(30, true);}@Override//可以重写空布局的UIpublic int getEmptyViewRes(int type) {switch (type) {case EmptyViewType.ERROR:return R.layout.layout_frame_error_view;case EmptyViewType.LOADING:return R.layout.layout_frame_loading_view;case EmptyViewType.REFRESH:return R.layout.layout_frame_refresh_view;default:return R.layout.layout_frame_empty_view;}}
}

大家找到EmptyRefreshActivity这个界面，在布局文件中，我加了一个SwipeRefreshLayout下拉刷新控件，在里面，绑定了app:OnRefreshListener="@{vm.refreshListener}"和app:refreshing="@{vm.isRefreshing}"，其中refreshListener这个是下拉监听器，我的baseViewModel中，写了监听回调，

//下拉刷新控件的监听器,里面调用重新加载数据的方法public SwipeRefreshLayout.OnRefreshListener getRefreshListener() {return new SwipeRefreshLayout.OnRefreshListener() {@Overridepublic void onRefresh() {isRefreshing.set(true);reload();}};}

如果下拉了，就会调用重新加载的方法。而isRefreshing这个是刷新判断，因为跟下拉控件绑定在一起，所以下拉的时候，可以反应刷新控件的状态。然后在RecyclerView中，我绑定了app:cs_brvah_emptyClickListener="@{vm.emptyOnClickListener}" 和app:cs_brvah_emptyResId="@{vm.emptyResId}"，第一个是绑定空布局的点击事件，下面是baseViewModel的部分相关代码

//空布局的点击事件,里面做判断,如果当前空布局不是正在加载的状态,点击之后,就重新获取数据protected View.OnClickListener getEmptyOnClickListener() {return new View.OnClickListener() {@Overridepublic void onClick(View v) {CSLog.Print("点击了空布局按钮");if (emptyResId.get() != getEmptyViewRes(EmptyViewType.LOADING)) {reload();emptyResId.set(getEmptyViewRes(EmptyViewType.LOADING));}}};}

当点击空布局时，如果当前不是正在加载的状态，就重新获取数据。

第二个vm.emptyResId是空布局的绑定，你可以在每个viewModel中，重写getEmptyViewRes这个方法，就可以定制空布局了。

侧滑删除和拖动

好，先来讲侧滑删除，大家找到SwipeActivity这个界面

public class SwipeViewModel extends BaseBindingViewModel<SimpleData> {private boolean isSwipe = true;。。。@Override//只要重写这个监听器,然后再布局中绑定,就能侧滑删除public OnItemSwipeListener getItemSwipeListener() {return new OnItemSwipeListener() {@Overridepublic void onItemSwipeStart(RecyclerView.ViewHolder viewHolder, int i) {}@Overridepublic void clearView(RecyclerView.ViewHolder viewHolder, int i) {}@Overridepublic void onItemSwiped(RecyclerView.ViewHolder viewHolder, int i) {}@Overridepublic void onItemSwipeMoving(Canvas canvas, RecyclerView.ViewHolder viewHolder, float v, float v1, boolean b) {canvas.drawColor(ContextCompat.getColor(FramGroble.INSTANCE.getTopActivity(), R.color.colorAccent));}};}
//这边是一个控制侧滑开关的例子,通过获取Controller()来控制,我已经在适配器中封装好了public void onSwi(View view) {if (isSwipe) {isSwipe = false;bindingAdapter.getDraggableController().disableSwipeItem();} else {isSwipe = true;bindingAdapter.getDraggableController().enableSwipeItem();}}@Override//设置侧滑方向public int getOnSwipeMoveFrags() {return ItemTouchHelper.START | ItemTouchHelper.END;}
}

<androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/rv_show"android:layout_width="match_parent"android:layout_height="match_parent"app:cs_brvah_SwipeMoveFrags="@{vm.swipeMoveFrags}"app:cs_brvah_Decoration="@{vm.itemDecoration}"app:cs_brvah_OnItemSwipeListener="@{vm.onItemSwipeListener}"app:cs_brvah_adapter="@{vm.bindingAdapter}"/>

是不是也很简单，首先看viewModel,只要你重写了OnItemSwipeListener这个监听回调，然后在布局文件中，将该监听器绑定在布局中，app:cs_brvah_OnItemSwipeListener="@{vm.onItemSwipeListener}"就可以了，是不是很简单。然后你还可以设置滑动的方向，默认是向后滑动删除的，你可以通过getOnSwipeMoveFrags（）重写这个方法，进行设置，当然设置好了之后，别忘了在布局文件中去绑定。如果你想要设置滑动开关怎么办，那当然也是可以的，万能适配器通过一个Controller来进行控制，我已经封装在适配器里了，你可以通过bindingAdapter.getDraggableController()获取到，然后设置开关就可以，例子已经给出。

接下来是拖动功能

public class DragViewModel extends NonMultiViewModel {private boolean isSwipe = true;@Override//只要设置拖动监听器,就可以实现拖动功能public OnItemDragListener getItemDragListener() {return new OnItemDragListener() {@Overridepublic void onItemDragStart(RecyclerView.ViewHolder viewHolder, int i) {}@Overridepublic void onItemDragMoving(RecyclerView.ViewHolder viewHolder, int i, RecyclerView.ViewHolder viewHolder1, int i1) {}@Overridepublic void onItemDragEnd(RecyclerView.ViewHolder viewHolder, int i) {}};}
//拖动开关public void onSwi(View view) {if (isSwipe) {isSwipe = false;bindingAdapter.getDraggableController().disableDragItem();} else {isSwipe = true;bindingAdapter.getDraggableController().enableDragItem(bindingAdapter.getItemTouchHelper(null));}}
}

<androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/rv_show"android:layout_width="match_parent"android:layout_height="match_parent"app:cs_brvah_Decoration="@{vm.itemDecoration}"app:cs_brvah_OnItemDragListener="@{vm.onItemDragListener}"app:cs_brvah_adapter="@{vm.bindingAdapter}"app:cs_brvah_layoutManager="@{CSBrvahLayoutManager.grid(4)}"app:cs_brvah_multiType="@{vm.multiTypeDelegat}"app:cs_brvah_spansize="@{vm.spanSizeLookup}"/>

我这边拖动的viewModel,继承了另外一个NonMultiViewModel，因为界面是一样的。拖动跟侧滑很像，也只要重写getItemDragListener监听器就可以，然后在布局中，调用app:cs_brvah_OnItemDragListener="@{vm.onItemDragListener}"进行绑定。是不是超级简单。拖动的开关控制器，跟侧滑一样，也是调用getDraggableController()，不过打开拖动功能的时候，要注意bindingAdapter.getDraggableController().enableDragItem（）里面要传一个Touch，这个touch要通过bindingAdapter.getItemTouchHelper(null)方法去获取，因为在绑定的时候，已经生成了一个touch，可以保证唯一性。例子里面都有。

我这边将拖动跟侧滑功能合在一起，做了个例子，大家可以找到DragASwipeActivity这个类，调用方法是一模一样的，我这里就不再重复了。

Expand可扩展的多布局

public class ExpandViewModel extends BaseBindingViewModel<MultiItemEntity> {。。。
//当每次数据加载完成的时候，都会回调该方法，我在这边，将列表展开@Overridepublic void onDataLoadComplete() {bindingAdapter.expandAll();}//模拟获取数据,这边的数据要继承AbstractExpandableItemprivate Flowable<List<MultiItemEntity>> getData() {return Flowable.create(new FlowableOnSubscribe<List<MultiItemEntity>>() {@Overridepublic void subscribe(FlowableEmitter<List<MultiItemEntity>> emitter) throws Exception {ArrayList<MultiItemEntity> data = new ArrayList<>();for (int i = 0; i < 5; i++) {ExDataGrandFa exDataGrandFa = new ExDataGrandFa("点我有惊喜", "点我啊", R.mipmap.headerandfooter_img1);for (int j = 0; j < 3; j++) {ExDataFather exDataFather = new ExDataFather("点我啊", "来点我啊", R.mipmap.m_img1);for (int k = 0; k < 6; k++) {ExDataChild exDataChild = new ExDataChild("点我消失", R.mipmap.head_img1);exDataFather.addSubItem(exDataChild);}exDataGrandFa.addSubItem(exDataFather);}data.add(exDataGrandFa);}emitter.onNext(data);emitter.onComplete();}}, BackpressureStrategy.BUFFER);}@Overridepublic RecyclerView.ItemDecoration onitemDecoration() {return new NormaltemDecoration(10);}//最外面item的点击事件,里面调用item的扩展和收缩.public class GrandAct implements CSAction1<ExDataGrandFa> {@Overridepublic void call(ExDataGrandFa param) {if (param.isExpanded()) {bindingAdapter.collapse(items.indexOf(param));} else {bindingAdapter.expand(items.indexOf(param));}}}//第二个item的点击事件,调用里面item的扩展和说收缩public class FatherAct implements CSAction1<ExDataFather> {@Overridepublic void call(ExDataFather param) {if (param.isExpanded()) {bindingAdapter.collapse(items.indexOf(param));} else {bindingAdapter.expand(items.indexOf(param));}}}//最里面item的点击事件,将item从本列表中删除,记住有2个地方要删除,一个是items,第二个是它外层的item中的数据public class ChildAct implements CSAction1<ExDataChild> {@Overridepublic void call(ExDataChild param) {//这一部分删除其实也不难,我是直接抄官方的,先获取当前item的父item,将集合中item去掉,再从父item中删掉当前item,要删2次int positionAtAll = getParentPositionInAll(items.indexOf(param));items.remove(param);if (positionAtAll != -1) {IExpandable multiItemEntity = (IExpandable) bindingAdapter.getData().get(positionAtAll);multiItemEntity.getSubItems().remove(param);}}}/*** 该方法用于 IExpandable 树形列表。* 如果不存在 Parent，则 return -1。** @param position 所处列表的位置* @return 父 position 在数据列表中的位置*/public int getParentPositionInAll(int position) {List<MultiItemEntity> data = bindingAdapter.getData();MultiItemEntity multiItemEntity = bindingAdapter.getItem(position);if (isExpandable(multiItemEntity)) {IExpandable IExpandable = (IExpandable) multiItemEntity;for (int i = position - 1; i >= 0; i--) {MultiItemEntity entity = data.get(i);if (isExpandable(entity) && IExpandable.getLevel() > ((IExpandable) entity).getLevel()) {return i;}}} else {for (int i = position - 1; i >= 0; i--) {MultiItemEntity entity = data.get(i);if (isExpandable(entity)) {return i;}}}return -1;}public boolean isExpandable(MultiItemEntity item) {return item != null && item instanceof IExpandable;}}

布局的代码没什么好说的，就是常规调用，来看一下viewModel，是不是跟普通的多布局很像，也是实现了MultiItemEntity，不同的地方就是，它的item要继承AbstractExpandableItem这个类，跟BRVAH中的一样，其中的action是我写的每个item的点击事件监听。也很简单。

下拉刷新，上拉加载

下拉上拉这一部分用的还是挺多的，所以我要稍微着重讲解一下，先贴代码

public abstract class LoadMoreBindingViewModel<B> extends BaseBindingViewModel<B> {//加载更多布局,可以自定义public LoadMoreView loadMoreView;//加载更多结束public ObservableBoolean loadMoreEnd;//是否能够加载更多public ObservableBoolean loadMoreEnable;//加载更多完成public ObservableBoolean loadMoreSuccess;//上拉加载的监听回调public BaseQuickAdapter.RequestLoadMoreListener loadMoreListener;//当前页数,默认从0开始,可以设置默认值public int mPage;//每页加载返回的个数,按照这个来判断是否已经加到头了public int PageSize = 15;//默认从第几页开始加载public int defaultStart;public LoadMoreBindingViewModel() {super();loadMoreView = getLoadMoreView();loadMoreListener = getLoadMoreListener();loadMoreEnd = new ObservableBoolean();loadMoreEnable = new ObservableBoolean();loadMoreSuccess = new ObservableBoolean();}protected LoadMoreView getLoadMoreView() {return new LoadMoreView() {@Overridepublic int getLayoutId() {return R.layout.view_load_more;}@Overrideprotected int getLoadingViewId() {return R.id.load_more_loading_view;}@Overrideprotected int getLoadFailViewId() {return R.id.load_more_load_fail_view;}@Overrideprotected int getLoadEndViewId() {return R.id.load_more_load_end_view;}};}protected BaseQuickAdapter.RequestLoadMoreListener getLoadMoreListener() {return new BaseQuickAdapter.RequestLoadMoreListener() {@Overridepublic void onLoadMoreRequested() {loadMore();}};}private void loadMore() {CSLog.Print("加载更多调用了");load();}@Overridepublic void load() {load(mPage);}@Overrideprotected void load(Flowable<List<B>> flowable) {if (isRefreshing.get()) {emptyResId.set(getEmptyViewRes(EmptyViewType.REFRESH));} else {CSLog.Print("调用了正在加载界面");emptyResId.set(getEmptyViewRes(EmptyViewType.LOADING));}disposable = flowable.observeOn(AndroidSchedulers.mainThread()).subscribeOn(Schedulers.io()).subscribe(new Consumer<List<B>>() {@Overridepublic void accept(List<B> result) throws Exception {setData(result);}}, new Consumer<Throwable>() {@Overridepublic void accept(Throwable throwable) throws Exception {if (isRefreshing.get() || mPage == defaultStart) {emptyResId.set(getEmptyViewRes(EmptyViewType.ERROR));loadMoreEnable.set(true);} else {loadMoreSuccess.set(false);loadMoreSuccess.notifyChange();}isRefreshing.set(false);}}, new Action() {@Overridepublic void run() throws Exception {loadMoreEnable.set(true);emptyResId.set(getEmptyViewRes(EmptyViewType.EMPTY));isRefreshing.set(false);mPage++;}});}//重新加载,页数清空@Overridepublic void reload() {mPage = defaultStart;super.reload();}//设置默认从第几页开始加载public void setDefaultStart(int index) {defaultStart = index;mPage = index;}public void setData(List<B> dat) {addItems(dat);if (dat.size() < getPageSize()) {loadMoreEnd.set(mPage == defaultStart);loadMoreEnd.notifyChange();} else {loadMoreSuccess.set(true);loadMoreSuccess.notifyChange();}}public abstract void load(int mPage);public int getPageSize() {return PageSize;}public void setPageSize(int pageSize) {this.PageSize = pageSize;}
}

public class LoadMoreLineViewModel extends LoadMoreBindingViewModel<SimpleData> {private boolean isFirst = true;
//构造方法中,设置每页获取的个数,这个值是用来判断当前网络请求,是否是最后一页的数据public LoadMoreLineViewModel() {super();setPageSize(10);}@Overrideprotected Map<Integer, CSBravhItemBinding> getItemBinding() {Map<Integer, CSBravhItemBinding> mp = new HashMap<>();mp.put(0, new CSBravhItemBinding(com.caesar.brvahbinding.BR.bean, R.layout.item_simple));return mp;}
//模拟加载数据,模拟加载成功/失败和结束@Overridepublic void load(int mPage) {CSLog.Print("当前加载的页:" + mPage);if (mPage == 2) {if (isFirst) {isFirst = false;load(getErr());} else {load(getSimp());}} else if (mPage == 3) {load(getFsa());} else {load(getSimp());}}public Flowable<List<SimpleData>> getSimp() {return Flowable.create(new FlowableOnSubscribe<List<SimpleData>>() {@Overridepublic void subscribe(FlowableEmitter<List<SimpleData>> emitter) throws Exception {ArrayList<SimpleData> data = new ArrayList<>();data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img1));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img2));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img3));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img2));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img1));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img3));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img2));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img1));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img3));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img2));emitter.onNext(data);emitter.onComplete();}}, BackpressureStrategy.BUFFER).delay(3, TimeUnit.SECONDS);}public Flowable<List<SimpleData>> getErr() {return Flowable.create(new FlowableOnSubscribe<List<SimpleData>>() {@Overridepublic void subscribe(FlowableEmitter<List<SimpleData>> emitter) throws Exception {emitter.onError(null);}}, BackpressureStrategy.BUFFER).delay(3, TimeUnit.SECONDS);}public Flowable<List<SimpleData>> getFsa() {return Flowable.create(new FlowableOnSubscribe<List<SimpleData>>() {@Overridepublic void subscribe(FlowableEmitter<List<SimpleData>> emitter) throws Exception {ArrayList<SimpleData> data = new ArrayList<>();data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img1));data.add(new SimpleData("这货是个标题", "这货是个内容加描述", R.mipmap.animation_img2));emitter.onNext(data);emitter.onComplete();}}, BackpressureStrategy.BUFFER).delay(3, TimeUnit.SECONDS);}@Overridepublic RecyclerView.ItemDecoration onitemDecoration() {return new NormalLineDecoration(30, true);}}

 <androidx.swiperefreshlayout.widget.SwipeRefreshLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"app:OnRefreshListener="@{vm.refreshListener}"app:refreshing="@{vm.isRefreshing}"><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/rv_show"android:layout_width="match_parent"android:layout_height="match_parent"android:padding="5dp"app:cs_brvah_Decoration="@{vm.itemDecoration}"app:cs_brvah_emptyResId="@{vm.emptyResId}"app:cs_brvah_emptyClickListener="@{vm.emptyOnClickListener}"app:cs_brvah_adapter="@{vm.bindingAdapter}"app:cs_brvah_loadMoreEnd="@{vm.loadMoreEnd}"app:cs_brvah_loadMoreEnable="@{vm.loadMoreEnable}"app:cs_brvah_loadMoreListener="@{vm.loadMoreListener}"app:cs_brvah_loadMoreSuccess="@{vm.loadMoreSuccess}"app:cs_brvah_loadMoreView="@{vm.loadMoreView}"/></androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

好，大家先找到LoadMoreLineActivity界面，仔细的同学就会发现，这边的viewModel我继承的是LoadMoreBindingViewModel，而LoadMoreBindingViewModel又是继承BaseBindingViewModel。

我们先看LoadMoreBindingViewModel，里面，新增加了一些属性，有LoadMoreView loadMoreView，这个是上拉加载的动画，可以用户自己定制，只要重写getLoadMoreView方法就可以了。bservableBoolean loadMoreEnd这个是判断是否已经加载结束。其中最关键的是新增的属性mPage，加载更多是有页数的，所以mPage这个值，就表示当前加载的是第几页，默认0，也可以设置从第1页开始加载。PageSize这个属性是判断是否已经加载到尾部，如果你加载回来的个数，小于这个值，就表示已经加载到头了。defaultStart这个值，是判断初始是从第几页开始加载。

好，接下来我们来看看LoadMoreLineViewModel这个类，其实也简单，就是一些常规的调用，不过原先重写的load（）回调中，里面加了一个int mpage参数，这个就是当前加载的页数。然后数据请求加载的方式，跟原先的是一样的。

最后来看一下布局文件的代码。下拉刷新控件的绑定我上面已经讲过了，这边就不讲了，主要是列表的绑定，如果你是想要你的布局支持加载更多的话，其中，app:cs_brvah_loadMoreEnd="@{vm.loadMoreEnd}" app:cs_brvah_loadMoreEnable="@{vm.loadMoreEnable}" app:cs_brvah_loadMoreListener="@{vm.loadMoreListener}" app:cs_brvah_loadMoreSuccess="@{vm.loadMoreSuccess}"app:cs_brvah_loadMoreView="@{vm.loadMoreView}"

是必须要加的，判断加载状态，加载监听，加载时的动画等等，直接照写就完事。

  @BindingAdapter(value = {"cs_brvah_loadMoreEnd"})public static void onLoadMoreEnd(RecyclerView recyclerView, ObservableBoolean loadMoreEnd) {CSLog.Print("加载结束调用:" + loadMoreEnd.get());RecyclerView.Adapter adapter = recyclerView.getAdapter();if (adapter instanceof BaseQuickAdapter) {CSLog.Print("进入加载结束调用:" + loadMoreEnd.get());((BaseQuickAdapter) adapter).loadMoreEnd(loadMoreEnd.get());}}@BindingAdapter(value = {"cs_brvah_loadMoreEnable"})public static void onLoadMoreEnable(RecyclerView recyclerView, ObservableBoolean loadMoreEnable) {CSLog.Print("是否加载更多:" + loadMoreEnable.get());RecyclerView.Adapter adapter = recyclerView.getAdapter();if (adapter instanceof BaseQuickAdapter) {CSLog.Print("进入是否加载更多:" + loadMoreEnable.get());((BaseQuickAdapter) adapter).setEnableLoadMore(loadMoreEnable.get());}}@BindingAdapter(value = {"cs_brvah_loadMoreSuccess"})public static void onLoadMoreSuccess(RecyclerView recyclerView, ObservableBoolean loadMoreSuccess) {CSLog.Print("是否加载成功:" + loadMoreSuccess.get());RecyclerView.Adapter adapter = recyclerView.getAdapter();if (adapter instanceof BaseQuickAdapter) {CSLog.Print("进入是否加载成功:" + loadMoreSuccess.get());if (loadMoreSuccess.get()) {((BaseQuickAdapter) adapter).loadMoreComplete();} else {((BaseQuickAdapter) adapter).loadMoreFail();}}}@BindingAdapter(value = {"cs_brvah_emptyResId", "cs_brvah_emptyClickListener"})public static void onEmptyView(RecyclerView recyclerView, ObservableInt emptyResId, View.OnClickListener clickListener) {CSLog.Print("加载空布局调用");RecyclerView.Adapter adapter = recyclerView.getAdapter();if (adapter instanceof BaseQuickAdapter) {if (emptyResId != null) {CSLog.Print("进入加载空布局");((BaseQuickAdapter) adapter).setEmptyView(emptyResId.get(), (ViewGroup) recyclerView.getParent());}if (clickListener != null && ((BaseQuickAdapter) adapter).getEmptyView() != null) {CSLog.Print("进入加载空布局监听事件");((BaseQuickAdapter) adapter).getEmptyView().setOnClickListener(clickListener);}}}

上面这些是CSBrvahBindingAdapter中，databinding绑定的代码。其实归根到底，还是调用了BRVAH的方法。

哇，又写了这么多了，那再起一页吧。

BRVAH的BaseRecyclerViewAdapterHelper与MVVM模式优雅结合（其一）

BRVAH的BaseRecyclerViewAdapterHelper与MVVM模式优雅结合（其三）