Recycler View - 一個視圖打開另一個視圖

Question

我有一個回收站視圖的問題。我有幾張可以擴展的卡片視圖。當我點擊其中一個並向下滾動時，另一個也被打開，但是當我向後滾動時，應該打開的那個被關閉。它不一致，很混亂，我甚至不知道如何描述它。感謝您的幫助。

回收站查看商品佈局：

<android.support.v7.widget.CardView 
xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:layout_marginBottom="@dimen/card_margin_bottom" 
android:layout_marginLeft="@dimen/card_margin_sides" 
android:layout_marginRight="@dimen/card_margin_sides" 
android:layout_marginTop="@dimen/card_margin_top"> 

<LinearLayout 
    style="@style/Widget.CardContent" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content"> 


    <TextView 
     android:id="@+id/headerText" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="@style/TextAppearance.AppCompat.Title" 
     android:textSize="@dimen/adapter_card_view_title_text_size"/> 


    <TextView 
     android:id="@+id/expandText" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_marginTop="20dp" 
     android:textSize="@dimen/adapter_card_view_expand_text_size" 
     android:visibility="gone"/> 

</LinearLayout> 

適配器：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> { 
private String[] headerText; 
private String[] techniqueText; 

public static class ViewHolder extends RecyclerView.ViewHolder { 
    public TextView headerText; 
    public TextView expandText; 
    public CardView mCardView; 

    public ViewHolder(CardView v) { 
     super(v); 
     mCardView = v; 
     headerText = (TextView) v.findViewById(R.id.headerText); 
     expandText = (TextView) v.findViewById(R.id.expandText); 
    } 
} 

public RecyclerViewAdapter(String[] firstParam, String[] secondParam) { 
    headerText = firstParam; 
    techniqueText = secondParam; 
} 

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

    ViewHolder vh = new ViewHolder((CardView) v,parent.getContext()); 
    return vh; 
} 

@Override 
public void onBindViewHolder(final ViewHolder holder, int position) { 
    holder.headerText.setText(headerText[position]); 
    holder.expandText.setText(techniqueText[position]); 
    holder.mCardView.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      if (holder.expandText.getVisibility() == View.GONE) { 
       holder.expandText.setVisibility(View.VISIBLE); 
      } 
      else if (holder.expandText.getVisibility() == View.VISIBLE){ 
       holder.expandText.setVisibility(View.GONE); 
      } 
     } 
    }); 
} 

@Override 
public int getItemCount() { 
    return headerText.length; 
} 

}

回收站V瀏覽器設置：

mRecyclerView = (RecyclerView) v.findViewById(R.id.recycler_x); 
    mRecyclerView.setHasFixedSize(false); 
    mLayoutManager = new LinearLayoutManager(this.getContext()); 
    mRecyclerView.setLayoutManager(mLayoutManager); 
    mAdapter = new RecyclerViewAdapter(firstParam,secondParam); 
    mRecyclerView.setAdapter(mAdapter); 

Answer 1

您的意見正在回收。如果您打開視圖並向下滾動，則該佈局（處於打開狀態）將被回收用於新條目，該條目也將顯示爲打開狀態。您需要回收時重置每個視圖的狀態，就像這樣：

private final Set<Integer> mOpenIndices = new HashSet<>(); 

@Override 
public void onBindViewHolder(final ViewHolder holder, final int position) { 
    holder.headerText.setText(headerText[position]); 
    holder.expandText.setText(techniqueText[position]); 

    if (mOpenIndices.contains(position)) { 
     holder.expandText.setVisibility(View.VISIBLE); 
    } else { 
     holder.expandText.setVisibility(View.GONE); 
    } 

    holder.mCardView.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      if (holder.expandText.getVisibility() == View.GONE) { 
       holder.expandText.setVisibility(View.VISIBLE); 
       mOpenIndices.add(position); 
      } 
      else if (holder.expandText.getVisibility() == View.VISIBLE){ 
       holder.expandText.setVisibility(View.GONE); 
       mOpenIndices.remove(position); 
      } 
     } 
    }); 
} 

現在你只需要跟蹤視圖狀態（開/關）。例如，您可以使用一組包含開放視圖索引的整數，或者您喜歡的其他解決方案。

Answer 2

RecyclerView的概念是它只爲可見物品創建了幾個視圖，當它們超出屏幕限制時，這些視圖會被回收。這對於大型列表（想象數百或數千個項目）在內存和性能方面產生巨大差異。

發生在你身上的是視圖被回收並因此失去其狀態。您需要明確存儲狀態並將其恢復到onBindViewHolder。喜歡的東西：

@Override 
public void onBindViewHolder(final ViewHolder holder, int position) { 
    holder.headerText.setText(headerText[position]); 
    holder.expandText.setText(techniqueText[position]); 
    holder.expandText.setVisibility(expanded[position] ? View.VISIBLE: View.GONE); 
    holder.mCardView.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      expanded[position] = !expanded[position] 
      holder.expandText.setVisibility(expanded[position] ? View.VISIBLE: View.GONE); 
     } 
    }); 
} 

這意味着，你需要一個額外的ArrayList稱爲expanded的大小大到足以容納你的狀態。