在Recycler視圖中保留項目的狀態

Question

我有一個從API填充數據的回收站視圖。每行有一個類似的按鈕，用戶可以按下並更改圖標的顏色。

當用戶按下按鈕時，它可以正常工作，但是當他向上滾動頁面然後回到喜歡的行時，類似的東西就消失了，看起來從未被按過。

我該如何保持這個「喜歡」狀態？

public class SocialAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { 

    ... 

    public SocialAdapter(Context context, JSONArray pages){ 
     mContext = context; 
     mPages = pages; 
... 
    } 
    @Override 
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 

     View view = LayoutInflater.from(mContext).inflate(R.layout.social_row, parent, false); 
     MyHolder holder=new MyHolder(view); 
     return holder; 
    } 

    @Override 
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) { 
     MyHolder myHolder= (MyHolder) holder; 

     try { 
      JSONObject mpackid = mPages.getJSONObject(position); 

      //myHolder.button_like.setText("Eu quero!"); 
      myHolder.button_like.setEnabled(true); 
      myHolder.button_like.setBackground(mContext.getResources().getDrawable(R.drawable.empty_star)); 
      myHolder.number_likes.setText(mpackid.optJSONObject("info").optString("likes")+" foo"); 
      myHolder.number_likes.setTextColor(Color.parseColor("#525252")); 

      myHolder.user_name.setText(mpackid.optString("user_full_name")); 
      myHolder.user_text.setText(mpackid.optJSONObject("info").optString("text")); 
      myHolder.feed_id.setText(mpackid.optJSONObject("info").optString("feed_suggestion_id")); 
      myHolder.number_likes.setText(mpackid.optJSONObject("info").optString("likes")+" foo"); 
      myHolder.like_int.setText(mpackid.optJSONObject("info").optString("likes")); 

      myHolder.tags.setText("#"+mpackid.optJSONObject("info").optJSONArray("tags").toString().replace("[", "").replace("]", "").replace("\"","")); 
      myHolder.date.setText(mpackid.optJSONObject("info").optString("elapsed_time")); 

      String likes = mpackid.optJSONObject("info").optJSONArray("liked_by").toString().replace("[", "").replace("]", "").replace("\"",""); 

      if(likes.contains(mUserId)){ 
       myHolder.button_like.setEnabled(false); 
       myHolder.button_like.setBackground(mContext.getResources().getDrawable(R.drawable.filled_star)); 
       myHolder.number_likes.setText("foo "+mpackid.optJSONObject("info").optString("likes")+" foo"); 
       myHolder.number_likes.setTextColor(Color.parseColor("#525252")); 
      } 

      Glide.with(mContext).load(mpackid.optString("user_avatar_url")) 
        .asBitmap() 
        .thumbnail(Glide.with(mContext).load(R.drawable.ajax_loader).asBitmap()) 
        .fitCenter() 
        .into(myHolder.user_image); 

     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
    } 

    @Override 
    public long getItemId(int position) { 
     return 0;// not using this 
    } 

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


    private static class ViewHolder{ 
     ImageView icon; 
     TextView itemName; 
     TextView url; 
    } 
    class MyHolder extends RecyclerView.ViewHolder{ 

     CircleImageView user_image; 
     TextView user_name; 
     TextView user_text; 
     TextView feed_id; 
     TextView number_likes; 
     TextView like_int; 
     TextView date; 
     TextView tags; 
     ImageButton button_like; 

     // create constructor to get widget reference 
     public MyHolder(View itemView) { 
      super(itemView); 
      user_image = (CircleImageView) itemView.findViewById(R.id.user_image); 
      user_name = (TextView) itemView.findViewById(R.id.user_name); 
      user_text = (TextView) itemView.findViewById(R.id.headline); 
      number_likes = (TextView) itemView.findViewById(R.id.number_likes); 
      feed_id = (TextView) itemView.findViewById(R.id._id); 
      like_int = (TextView) itemView.findViewById(R.id.likes_nb); 
      button_like = (ImageButton) itemView.findViewById(R.id.button5); 
      date = (TextView) itemView.findViewById(R.id.date); 
      tags = (TextView) itemView.findViewById(R.id.feed_tag); 
     } 

    } 

    public JSONObject getItem(int position) { 
     try { 
      return mPages.getJSONObject(position); 
     } catch (JSONException e) { 
      e.printStackTrace(); 
      return null; 
     } 
    } 
    public void addMoreData(JSONArray loadMoreArray) throws JSONException { 
     //Seta data pra LoadArray 
     mPages.length(); 
     this.mPages = mPages.put(loadMoreArray.getJSONObject(0)); 
     notifyItemRangeInserted(mPages.length(), mPages.length()+1); 
     SmoothRecyclerView recyclerView = (SmoothRecyclerView) ((Activity) this.mContext).findViewById(R.id.chat_social); 
     recyclerView.scrollToPosition(mPages.length()-1); 

    } 

Answer 1

你必須使用if內部的onBindViewHolder。

if(likes.contains(mUserId)){ 
      myHolder.button_like.setEnabled(false); 
      myHolder.button_like.setBackground(mContext.getResources().getDrawable(R.drawable.filled_star)); 
      myHolder.number_likes.setText("foo "+mpackid.optJSONObject("info").optString("likes")+" foo"); 
      myHolder.number_likes.setTextColor(Color.parseColor("#525252")); 
     } 
else{ 
    //behaviour when like.contains(userId) is false. 
} 

這是因爲觀點持有者將回收前一個項目的看法，如用戶滾動，所以u有這樣觀點持有人的行爲就有望如果其他人使用這兩種方案。