垂直recyclerview（其中包括horizo​​ntal recyclerview）无法正常工作

Question

我有一个包含两个回收站视图（垂直和水平）的片段。

我为这两个回收站视图编写了所有适配器（受this answer的启发），但问题是外部（垂直）recyclerview仅显示第一个项目，并未显示其余项目。我试图代码如下：

aFragment.java

... 
recyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerView); 
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity()) { 
    @Override 
    public boolean canScrollVertically() { 
     return false; 
    } 
}; 
recyclerView.setLayoutManager(layoutManager); 
adapter = new AppletCategoryAdapter(applets, getActivity()); 
recyclerView.setAdapter(adapter); 
recyclerView.setItemAnimator(new DefaultItemAnimator()); 
adapter.notifyDataSetChanged(); 
... 

AppletCategoryAdapter.java：

public class AppletCategoryAdapter extends RecyclerView.Adapter<AppletCategoryAdapter.SimpleViewHolder> { 

    private Context mContext; 
    private List<AppletItemsCategory> mData; 
    ... 

    public class SimpleViewHolder extends RecyclerView.ViewHolder { 
     public final TextView title; 
     public RecyclerView horizontalList; 

     public SimpleViewHolder(View view) { 
      super(view); 
      this.title = (TextView) view.findViewById(R.id.applet_category_item_name); 
      this.horizontalList = (RecyclerView) itemView.findViewById(R.id.applet_items_horizontal_list); 
      this.horizontalList.setLayoutManager(new LinearLayoutManager(horizontalList.getContext(), LinearLayoutManager.HORIZONTAL, false)); 
      this.horizontalList.setNestedScrollingEnabled(false); 
      horizontalList.setAdapter(null); 
     } 
    } 


    public AppletCategoryAdapter(List<AppletItemsCategory> data, Context context) { 
     mData = data; 
     mContext = context; 
    } 

    public SimpleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
     View view = LayoutInflater.from(mContext).inflate(R.layout.applet_category_item, parent, false); 
     return new SimpleViewHolder(view); 
    } 

    @Override 
    public void onBindViewHolder(SimpleViewHolder holder, final int position) { 
     List<Applet> applets = mData.get(position).getProductOffers(); 
     holder.title.setText(mData.get(position).getCategoryName()); 
     AppletCardAdapter appletCardAdapter = new AppletCardAdapter(applets,mContext); 
     holder.horizontalList.setLayoutManager(new LinearLayoutManager(mContext, LinearLayoutManager.HORIZONTAL, false)); 
     holder.horizontalList.setAdapter(appletCardAdapter); 
     holder.horizontalList.setNestedScrollingEnabled(false); 
     appletCardAdapter.notifyDataSetChanged(); 
    } 

    @Override 
    public int getItemCount() { 
     return mData.size(); 
    } 
} 

AppletCardAdapter.java：

public class AppletCardAdapter extends RecyclerView.Adapter<AppletCardAdapter.ViewHolder> { 
    private ImageLoader imageLoader; 
    private Context context; 

    //List of channels 
    List<Applet> applets; 

    public AppletCardAdapter(List<Applet> applets, Context ctx) { 
     this.applets = applets; 
     this.context = ctx; 
    } 

    @Override 
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
     View v = LayoutInflater.from(parent.getContext()) 
       .inflate(R.layout.applets_list, parent, false); 
     ViewHolder viewHolder = new ViewHolder(v); 
     return viewHolder; 
    } 

    @Override 
    public void onBindViewHolder(ViewHolder holder, int position) { 
     final Applet applet = applets.get(position); 
     holder.setIsRecyclable(true); 
     imageLoader = CustomVolleyRequest.getInstance(context).getImageLoader(); 
     imageLoader.get(Config.BASE_URL + applet.getImage(), ImageLoader.getImageListener(holder.imageView, R.mipmap.ic_launcher, android.R.drawable.ic_dialog_alert)); 
     holder.imageView.setImageUrl(Config.BASE_URL + applet.getImage(), imageLoader); 
     holder.textViewName.setText(applet.getName()); 
     holder.textViewDescription.setText(applet.getDescription()); 
     try { 
      holder.cardView.setCardBackgroundColor(Color.parseColor(applet.getColor())); 
     } 
     catch (Exception e) { 
      Log.d("iotel", "Unknown color"); 
     } 
     holder.cardView.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       openAppletDetailFragment(applet); 
      } 
     }); 
    } 

    @Override 
    public int getItemCount() { 
     return applets.size(); 
    } 

    class ViewHolder extends RecyclerView.ViewHolder{ 
     public NetworkImageView imageView; 
     public TextView textViewName; 
     public TextView textViewDescription; 
     public CardView cardView; 

     public ViewHolder(View itemView) { 
      super(itemView); 
      imageView = (NetworkImageView) itemView.findViewById(R.id.appletImage); 
      textViewName = (TextView) itemView.findViewById(R.id.appletName); 
      textViewDescription = (TextView) itemView.findViewById(R.id.appletDescription); 
      cardView = (CardView) itemView.findViewById(R.id.appletCard); 
     } 
    } 
} 

a_fragment.xml：（含有垂直recyclerView）

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.NestedScrollView 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

<LinearLayout android:layout_width="match_parent" 
    android:orientation="vertical" 
    android:layout_height="match_parent" 
    tools:context=".MainActivity"> 
    <ProgressBar 
     android:id="@+id/progressBar1" 
     style="?android:attr/progressBarStyleInverse" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_gravity="center" 
     android:visibility="invisible"/> 

    <android.support.v4.view.ViewPager 
     android:id="@+id/pager" 
     android:layout_width="fill_parent" 
     android:layout_height="250dp" 
     android:focusableInTouchMode="true"/> 

    <android.support.v7.widget.RecyclerView 
     android:id="@+id/recyclerView" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior"> 
    </android.support.v7.widget.RecyclerView> 
</LinearLayout> 

</android.support.v4.widget.NestedScrollView> 

applet_category_item.xml（含有水平recyclerView）：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_marginTop="15dp" 
    android:layout_marginBottom="15dp"> 

    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:orientation="vertical" 
     android:layout_alignParentRight="true"> 

     <TextView 
      android:id="@+id/applet_category_item_name" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content"/> 

     <android.support.v7.widget.RecyclerView 
      android:id="@+id/applet_items_horizontal_list" 
      android:layout_width="match_parent" 
      android:layout_marginTop="5dp" 
      android:layout_height="160dp" 
      android:layout_gravity="center" 
      app:layout_behavior="@string/appbar_scrolling_view_behavior"/> 

    </LinearLayout> 

</RelativeLayout> 

applet_list.xml（示出每个项目的内容在水平recyclerView中）：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:padding="5dp"> 

    <android.support.v7.widget.CardView 
     android:layout_width="150dp" 
     android:layout_height="150dp" 
     style="@style/MyCardViewStyle" 
     app:cardBackgroundColor="@color/cardDefaultBg" 
     app:cardCornerRadius="15dp" 
     android:foreground="?android:attr/selectableItemBackground" 
     android:clickable="true" 
     android:id="@+id/appletCard"> 

     <LinearLayout 
      android:orientation="horizontal" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content"> 

      <com.android.volley.toolbox.NetworkImageView 
       android:layout_width="50dp" 
       android:layout_height="50dp" 
       android:layout_gravity="center" 
       android:id="@+id/appletImage" /> 
      <LinearLayout 
       android:padding="8dp" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:orientation="vertical"> 
       <ir.iotel.MyTextView 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:textStyle="bold" 
        android:layout_gravity="end" 
        android:textSize="9pt" 
        android:textColor="@color/fontSecondary" 
        android:id="@+id/appletName" /> 
       <ir.iotel.MyTextView 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_gravity="end" 
        android:textColor="@color/fontSecondary" 
        android:id="@+id/appletDescription" /> 
      </LinearLayout> 
     </LinearLayout> 
    </android.support.v7.widget.CardView> 

</LinearLayout > 

Answer 1

看看这段代码：https://github.com/hardworker93/carousels/tree/master

你应该试试这个：

在片段

mLayoutManager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);  
mRecyclerView.setLayoutManager(mLayoutManager); 
mRecyclerView.setHasFixedSize(true); 

适配器：

@Override 
    public void onBindViewHolder(ViewHolder holder, int position) { 

     List<Item> RowItems = mRows.get(position); 
     LinearLayoutManager layoutManager = new LinearLayoutManager(mContext,LinearLayoutManager.HORIZONTAL,false);  
     holder.mRecyclerViewRow.setLayoutManager(layoutManager); 
     holder.mRecyclerViewRow.setHasFixedSize(true); 
     RowRecyclerAdapter rowsRecyclerAdapter = new RowRecyclerAdapter(mContext,RowItems);   
     holder.mRecyclerViewRow.setAdapter(rowsRecyclerAdapter); 

在布局applet_category_item：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="150dp" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_marginTop="15dp" 
    android:layout_marginBottom="15dp"> 

Answer 2

几个小时后，我终于克服了这个问题。 Adapter，Fragment和RecyclerViews背后的逻辑是正确和完整的功能。即使它可以用作实现嵌套的回收站视图的模板（水平回收视图在垂直回收视图内）。然而，在水平回收器视图（applet_category_item.xml）的设计上的一个小错误导致应用程序上的一个巨大的错误。

长话短说，看来RelativeLayout不应该用在这种情况下。当我删除它，所有的事情进展顺利，生活变得更甜:)

<LinearLayout 
    android:layout_height="match_parent" 
    android:layout_width="match_parent" 
    android:gravity="right" 
    android:orientation="vertical" 
    android:layout_margin="10dp"> 

    <TextView 
     android:id="@+id/applet_category_item_name" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:paddingTop="10dp" 
     android:paddingBottom="10dp" 
     android:textSize="17sp" /> 

    <android.support.v7.widget.RecyclerView 
      android:id="@+id/applet_items_horizontal_list" 
      android:layout_width="wrap_content" 
      android:layout_height="match_parent" 
      android:orientation="horizontal"/> 

</LinearLayout>