在NestedScrollView中使用Multiple Recyclerview不会发生视图回收 [英] View Recycling not happens with Multiple Recyclerview inside NestedScrollView

问题描述

我在管理 NestedScrollView 内的多个 Recyclerview 回收方面遇到问题.让我告诉我我想做什么-

1. 我有两种框架布局，即frame1和frame2.
2. 我有两个包含recyclerview的片段，第一个片段的recyclerview水平显示项目，而第二个片段的recyclerview纵向显示列表.
3. 现在我已经将两个 FrameLayout 放在一个 NestedScroolView 内，frame1 recyclerview正在正确地回收所有视图，但是frame2 recylerview没有在回收该视图，不知道为什么吗?首先加载所有项目，然后在屏幕上显示.

某些代码:

MainActivity.java

  FragmentTransaction事务；@Override受保护的void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);FragmentA frag1 = new FragmentA();FragmentB frag2 = new FragmentB();transaction = getSupportFragmentManager().beginTransaction();transaction.replace(R.id.frame1，frag1);transaction.addToBackStack(frag1.getClass().getName());transaction.commit();transaction = getSupportFragmentManager().beginTransaction();transaction.replace(R.id.frame2，frag2);transaction.addToBackStack(frag2.getClass().getName());transaction.commit();} 

main.xml

 < LinearLayoutxmlns:android ="http://schemas.android.com/apk/res/android"xmlns:app ="http://schemas.android.com/apk/res-auto"android:layout_width ="match_parent"android:layout_height ="wrap_content">< android.support.v4.widget.NestedScrollViewandroid:layout_width ="match_parent"android:layout_height ="match_parent"android:fillViewport ="true"app:layout_behavior ="@ string/appbar_scrolling_view_behavior">< LinearLayoutandroid:layout_width ="match_parent"android:layout_height ="wrap_content"android:orientation ="vertical">< FrameLayoutandroid:id ="@ + id/frame1"android:layout_width ="match_parent"android:layout_height ="185dp"/>< FrameLayoutandroid:id ="@ + id/frame2"android:layout_width ="match_parent"android:layout_height ="wrap_content"/></LinearLayout></android.support.v4.widget.NestedScrollView></LinearLayout> 

FragmentA:

  @Override公共视图onCreateView(LayoutInflater充气器，ViewGroup容器，捆绑的saveInstanceState){查看v = inflater.inflate(R.layout.recycler_view，container，false);mDataListView =(RecyclerView)v.findViewById(R.id.data_list_view);mDataListView .setHasFixedSize(true);最后的GridLayoutManager gridLayoutManager = new GridLayoutManager(getActivity()，getActivity().getResources().getInteger(R.integer.playlist_categories_columns)，GridLayoutManager.VERTICAL，false);mDataListView .setNestedScrollingEnabled(false);}}));返回v;} 

FragmentB:

  @Override公共视图onCreateView(LayoutInflater充气器，ViewGroup容器，捆绑的saveInstanceState){查看v = inflater.inflate(R.layout.recycler_view，container，false);mDataListView =(RecyclerView)v.findViewById(R.id.data_list_view);mDataListView .setHasFixedSize(true);最后的GridLayoutManager gridLayoutManager = new GridLayoutManager(getActivity()，1，GridLayoutManager.HORIZONTAL，false);mDataListView .setLayoutManager(gridLayoutManager);mDataListView .setNestedScrollingEnabled(false);}}));返回v;} 

recycler_view.xml

 <?xml version ="1.0" encoding ="utf-8"?>< android.support.v7.widget.RecyclerView xmlns:android ="http://schemas.android.com/apk/res/android"xmlns:app ="http://schemas.android.com/apk/res-auto"android:id ="@ + id/data_list_view"android:layout_width ="match_parent"android:layout_height ="wrap_content"app:layout_behavior ="@ string/appbar_scrolling_view_behavior"/> 

我希望我对我的问题很清楚.

解决方案

根据我的经验，我发现在 NestedScrollView 中使用多个 recyclerview's 不能进行视图回收.

但是我想出了解决方案，根据我的要求显示多个Recyclerview，我想在其顶部显示一个卧式Recyclerview，在其下方显示一个Vertical Recyclerview，所以我分享的内容可能对某人有帮助.

我删除了 NestedScrollView 作为 Recyclerview's 的父级，并将Horizo​​ntal Recyclerview 用作Vertical 的 HeaderView Recyclerview .

代码:

 公共类ListHeaderAdapter扩展了RecyclerView.Adapter< RecyclerView.ViewHolder>.{私有静态最终int TYPE_HEADER = 0;私有静态最终int TYPE_ITEM = 1;ArrayList< String>数据;public ListHeaderAdapter(ArrayList< String>数据){this.data =数据；}@Override公共RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent，int viewType){如果(viewType == TYPE_ITEM){//膨胀您的布局并将其传递给视图持有者返回新的VHItem(null);}否则，如果(viewType == TYPE_HEADER){//膨胀您的布局并将其传递给视图持有者返回新的VHHeader(null);}}@Overridepublic void onBindViewHolder(RecyclerView.ViewHolder持有人，int位置){int pos =位置-1；//用于处理Header视图(使用pos从列表中获取数据)if(VHItem的所有者实例){字符串dataItem = data.get(pos);//将持有人投射到VHItem并设置数据} else if(VHHeader的holder实例){//将持有者广播到VHHeader并设置标题的数据.}}@Overridepublic int getItemCount(){返回data.size()+ 1;//用于处理Header视图}@Overridepublic int getItemViewType(int position){如果(isHeader(position))返回TYPE_HEADER;返回TYPE_ITEM;}public boolean isHeader(int position){返回位置== 0;}VHItem类扩展了RecyclerView.ViewHolder {TextView标题；公共VHItem(查看itemView){超级(itemView);}}VHHeader类扩展了RecyclerView.ViewHolder {按钮按钮；公共VHHeader(查看itemView){超级(itemView);}}} 

注意:可以实施相同的逻辑以在任何位置显示水平 RecyclerView的

I am stuck with a issue in managing Multiple Recyclerview recycling inside a NestedScrollView. Let me tell what I am trying to do -

1. I have two frame layouts i.e. frame1 and frame2.
2. I have two fragments containing recyclerview , First fragment's recyclerview showing items horizontally while second fragment's recyclerview showing list Vertically.
3. Now I have put both FrameLayout inside a NestedScroolView, frame1 recyclerview is recycling all the view's properly but frame2 recylerview is not recycling the view , dont know why ? it first load all items then shows on screen.

Some Code :

MainActivity.java

 FragmentTransaction transaction;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
setContentView(R.layout.main);
FragmentA frag1=new FragmentA();
FragmentB frag2=new FragmentB();
transaction =    getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.frame1, frag1);
    transaction.addToBackStack(frag1.getClass().getName());
    transaction.commit();

 transaction =   getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.frame2, frag2);
    transaction.addToBackStack(frag2.getClass().getName());
    transaction.commit();
}

main.xml

  <LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

 <android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">
  <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <FrameLayout
            android:id="@+id/frame1"
            android:layout_width="match_parent"
            android:layout_height="185dp" />

        <FrameLayout
            android:id="@+id/frame2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
             />

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

FragmentA :

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View v= inflater.inflate(R.layout.recycler_view, container, false);
    mDataListView = (RecyclerView) v.findViewById(R.id.data_list_view);
    mDataListView .setHasFixedSize(true);
    final GridLayoutManager gridLayoutManager = new GridLayoutManager(getActivity(), getActivity().getResources().getInteger(R.integer.playlist_categories_columns), GridLayoutManager.VERTICAL, false);

    mDataListView .setNestedScrollingEnabled(false);
   }
    }));


    return v;
}

FragmentB :

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View v= inflater.inflate(R.layout.recycler_view, container, false);
    mDataListView = (RecyclerView) v.findViewById(R.id.data_list_view);
    mDataListView .setHasFixedSize(true);
     final GridLayoutManager gridLayoutManager = new    GridLayoutManager(getActivity(), 1, GridLayoutManager.HORIZONTAL, false);
    mDataListView .setLayoutManager(gridLayoutManager);

    mDataListView .setNestedScrollingEnabled(false);
   }
    }));


    return v;
}

recycler_view.xml

 <?xml version="1.0" encoding="utf-8"?>
 <android.support.v7.widget.RecyclerView    xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/data_list_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />

I hope I am clear with my question.

解决方案

From my Experience I found that view recycling is not possible with multiple recyclerview's inside a NestedScrollView.

But I figure out the solution to show multiple Recyclerview's as per my requirement i want to show one Horizontal Recyclerview on top and one Vertical Recyclerview below it so what i did I am sharing may it helps someone.

I removed the NestedScrollView as parent of Recyclerview's and made Horizontal Recyclerview as HeaderView of Vertical Recyclerview.

code :

public class ListHeaderAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int TYPE_HEADER = 0;
private static final int TYPE_ITEM = 1;
ArrayList<String> data;

public ListHeaderAdapter (ArrayList<String> data) {
    this.data = data;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == TYPE_ITEM) {
        //inflate your layout and pass it to view holder
        return new VHItem(null);
    } else if (viewType == TYPE_HEADER) {
        //inflate your layout and pass it to view holder
        return new VHHeader(null);
    }
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
 int pos = position - 1; // for handling of Header view(use pos to fetch data from list)

    if (holder instanceof VHItem) {
        String dataItem = data.get(pos);
        //cast holder to VHItem and set data
    } else if (holder instanceof VHHeader) {
        //cast holder to VHHeader and set data for header.
    }
}

@Override
public int getItemCount() {
    return data.size()+ 1; // for handling of Header view
}

@Override
public int getItemViewType(int position) {
    if (isHeader(position))
        return TYPE_HEADER;

    return TYPE_ITEM;
}

public boolean isHeader(int position) {
    return position == 0;
}


class VHItem extends RecyclerView.ViewHolder {
    TextView title;

    public VHItem(View itemView) {
        super(itemView);
    }
}

class VHHeader extends RecyclerView.ViewHolder {
    Button button;

    public VHHeader(View itemView) {
        super(itemView);
    }
}
}

Note : same logic can be implemented to show Horizontal RecyclerView's at any Position

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