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如何使用LiveData更新RecyclerView示例：SeenCounter，CommentCounter，LikeCounter

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所以我使用RecyclerView制作社交媒体应用程序，它具有类似按钮和类似计数器的功能。Mainactivity加载OnCreate时，它将在我的RecyclerView中单击“ http // test / getLikeCounter”以显示类似计数器，但是当我单击类似按钮时，它将击我自己的API“ http // test / setLikeCounter”并在数据库中添加计数器，但是由于它不会再次加载OnCreate方法，所以它不会在RecyclerView中添加我的Like计数器，我该如何刷新当我单击“喜欢”按钮时，RecyclerView是否动态？ 有人建议使用LiveData，但是如何以及在哪里实现呢？

这是当我在OnCreate中点击我的API时，它将在WebAPI.java中点击“ http // test / getLikeCounter” 

webAPI_.rncryptorALLDEWA("Trending");

我通过点击API接收了数据并转换了JSON文件，并使用EventBus将其发送回Mainactivity 

@Subscribe(threadmode = Threadmode.MAIN)
public void onmessageEvent(Mainactivity.EventStoredTrending event) {
    getTrendingMainactivity(event.SendDummyUrutan,event.SendTotalThread,event.SendDummyIDContent,event.SendDummyTitle,event.SendDummyPublishTime,event.SendDummyImageOri,event.SendDummyShortDescription,event.SendDummySeen,event.SendDummyComment,event.SendDummyLike);
}

之后，我将值手动设置为RecyclerView 

public void createDummyData1UPDATE(int ReceivedDummyUrutan,int ReceivedTotalThread,String ReceivedDummyIDContent,String ReceivedDummyTitle,String ReceivedDummyPublishTime,String ReceivedDummyImageOri,String ReceivedDummyShortDescription,int ReceivedDummySeen,int ReceivedDummyComment,int ReceivedDummyLike,int ReceivedDummyisComment,int ReceivedDummyisLike,int ReceivedDummyisBookmark) {
    modelSingleHotTrendingNews.add(new ModelSingleHotTrendingNews(ReceivedDummyIDContent,ReceivedDummyTitle,ReceivedDummyPublishTime,ReceivedDummyImageOri,ReceivedDummyShortDescription,ReceivedDummySeen,ReceivedDummyComment,ReceivedDummyLike,ReceivedDummyisComment,ReceivedDummyisLike,ReceivedDummyisBookmark,"x53535","No Error"));

    if(ReceivedDummyUrutan ==  ReceivedTotalThread-1){
        ModelSectionHotTrendingNews modelSectionHotTrendingNewsX = new ModelSectionHotTrendingNews();
        modelSectionHotTrendingNewsX.setHeaderTitle("TRENDING NEWS");
        modelSectionHotTrendingNewsX.setallItemsInSection(modelSingleHotTrendingNews);
        modelSectionHotTrendingNews.add(modelSectionHotTrendingNewsX);

        RecyclerViewSingleHotTrendingNews = v.findViewById(R.id.RecyclerView_Single_HotTrendingNews);
        RecyclerViewSingleHotTrendingNews.setHasFixedSize(true);
        adapterSectionHotTrendingNews = new AdapterSectionHotTrendingNews(getactivity(),modelSectionHotTrendingNews,listenerHotTrendingNews);
        RecyclerViewSingleHotTrendingNews.setLayoutManager(new LinearLayoutManager(getactivity(),LinearLayoutManager.VERTICAL,false));
        RecyclerViewSingleHotTrendingNews.setadapter(adapterSectionHotTrendingNews);
        //Optimized
        RecyclerViewSingleHotLatestNews.setHasFixedSize(true);
        RecyclerViewSingleHotLatestNews.setItemViewCacheSize(20);
    }

}

当我单击一个类似的按钮时，我想更新到我的RecyclerView，所以当数据库中的“ LikeCounter”增加时，RecyclerView会动态更新

webAPI_.rncryptorCommentLikeBookmark("isLike",modelSingleHotTrendingNews.get(position).getIdcontent(),modelSingleHotTrendingNews.get(position).getIslike());

这是HotSectionAdapter.java 

public class AdapterSectionHotTrendingNews extends RecyclerView.Adapter{

private Context mContext;
private ArrayList<ModelSectionHotTrendingNews> modelSectionHotTrendingNews;
private AdapterSingleHotTrendingNews.RecyclerViewClicklistener mListener;

public AdapterSectionHotTrendingNews(Context mContext,ArrayList<ModelSectionHotTrendingNews> modelSectionHotTrendingNews,AdapterSingleHotTrendingNews.RecyclerViewClicklistener mListener) {
    this.mContext = mContext;
    this.modelSectionHotTrendingNews = modelSectionHotTrendingNews;
    this.mListener = mListener;
}



@Override
        public SectionHotTrendingNewsViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
    View v = LayoutInflater.from(parent.getcontext()).inflate(R.layout.item_section_hottrendingnews,null);
    return new SectionHotTrendingNewsViewHolder(v);
}

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

    final SectionHotTrendingNewsViewHolder sectionHotTrendingNewsViewHolder = (SectionHotTrendingNewsViewHolder) holder;
    ModelSectionHotTrendingNews modelSectionHotTrendingNewsX = modelSectionHotTrendingNews.get(position);

    //Set
    sectionHotTrendingNewsViewHolder.TVSectionTitle.setText(modelSectionHotTrendingNewsX.getHeaderTitle());

    ArrayList singleSectionItems = modelSectionHotTrendingNewsX.getallItemsInSection();

    //WOW
    AdapterSingleHotTrendingNews itemListDataAdapter = new AdapterSingleHotTrendingNews(mContext,singleSectionItems,mListener);
    //WOW

    final String sectionTitle = modelSectionHotTrendingNewsX.getHeaderTitle();
    sectionHotTrendingNewsViewHolder.BTNHotTrendingNewsMore.setOnClicklistener(
            new View.OnClicklistener() { @Override public void onClick(View v) {
                Toast.makeText(v.getcontext(),"click event on more,"+sectionTitle,Toast.LENGTH_SHORT).show();
                Intent intent = new Intent(mContext,TabMoreHotactivity.class);
                // here you create put extra in new intent not the intent that you created

                intent.putExtra("MoreTrendingNews",modelSectionHotTrendingNews.get(position).getallItemsInSection());
                mContext.startactivity(intent);

            } });




    /*Glide.with(mContext)
            .load(feedItem.getImageURL())
            .diskCacheStrategy(DiskCacheStrategy.ALL)
            .centerCrop()
            .error(R.drawable.bg)
            .into(feedListRowHolder.thumbView);*/

    //SetRecyclerView
    sectionHotTrendingNewsViewHolder.RecyclerViewSectionHotTrendingNews.setHasFixedSize(true);
    sectionHotTrendingNewsViewHolder.RecyclerViewSectionHotTrendingNews.setLayoutManager(new LinearLayoutManager(mContext,LinearLayoutManager.HORIZONTAL,false));
    sectionHotTrendingNewsViewHolder.RecyclerViewSectionHotTrendingNews.setadapter(itemListDataAdapter);
    sectionHotTrendingNewsViewHolder.RecyclerViewSectionHotTrendingNews.setnestedScrollingEnabled(false);
}

@Override
public int getItemCount() {
    int itemCount = modelSectionHotTrendingNews.size();
    return itemCount;
}

public class SectionHotTrendingNewsViewHolder extends RecyclerView.ViewHolder {

    protected TextView TVSectionTitle;
    protected ImageView BTNHotTrendingNewsMore;
    protected RecyclerView RecyclerViewSectionHotTrendingNews;
    protected RecyclerView RecyclerViewMoreSectionHotTrendingNews;

    public SectionHotTrendingNewsViewHolder(View itemView) {
        super(itemView);

        TVSectionTitle = (TextView) itemView.findViewById(R.id.TV_SectionTitle);
        BTNHotTrendingNewsMore= (ImageView) itemView.findViewById(R.id.BTN_HotTrendingNewsMore);
        RecyclerViewSectionHotTrendingNews = (RecyclerView) itemView.findViewById(R.id.RecyclerView_Section_HotTrendingNews);
        RecyclerViewMoreSectionHotTrendingNews = (RecyclerView) itemView.findViewById(R.id.RecyclerViewMore_Section_HotTrendingNews);
    }

}

}

这是HotSingleAdapter.java 

public class AdapterSingleHotTrendingNews extends RecyclerView.Adapter{

private Context mContext;
private ArrayList<ModelSingleHotTrendingNews> modelSingleHotTrendingNews;

private RecyclerViewClicklistener mListener;


public AdapterSingleHotTrendingNews(Context mContext,ArrayList<ModelSingleHotTrendingNews> modelSingleHotTrendingNews,RecyclerViewClicklistener mListener) {
    this.mContext = mContext;
    this.modelSingleHotTrendingNews = modelSingleHotTrendingNews;
    this.mListener = mListener;
}

/*public void swap(ArrayList<ModelSingleHotTrendingNews> datas)
{
    modelSingleHotTrendingNews.clear();
    modelSingleHotTrendingNews.addAll(datas);
    notifyDataSetChanged();
}*/

public void swap(ArrayList list){
    if (modelSingleHotTrendingNews != null) {
        modelSingleHotTrendingNews.clear();
        modelSingleHotTrendingNews.addAll(list);
    }
    else {
        modelSingleHotTrendingNews = list;
    }
    notifyDataSetChanged();
}

//Container
@Override
public SingleHotTrendingNewsViewHolder onCreateViewHolder(ViewGroup viewGroup,int viewType) {
    View v = LayoutInflater.from(viewGroup.getcontext()).inflate(R.layout.item_single_hottrendingnews,null);
    return new SingleHotTrendingNewsViewHolder(v,mListener);
}

//Fill Container with Model Setter Getter
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder,final int position) {

    final SingleHotTrendingNewsViewHolder singleHotTrendingNewsViewHolder = (SingleHotTrendingNewsViewHolder) holder;
    final ModelSingleHotTrendingNews modelSingleHotTrendingNewsX = modelSingleHotTrendingNews.get(position);

    //Set
    singleHotTrendingNewsViewHolder.TVGameDate.setText(modelSingleHotTrendingNewsX.getGamedate());
    singleHotTrendingNewsViewHolder.TVGameTitle.setText(modelSingleHotTrendingNewsX.getGametitle());
    Glide.with(mContext).load(modelSingleHotTrendingNewsX.getGameimage()).into(singleHotTrendingNewsViewHolder.IMGGameImage);
    /*singleHotTrendingNewsViewHolder.IMGGameImage.setImageResource(modelSingleHotTrendingNewsX.getGameimage());*/

    singleHotTrendingNewsViewHolder.TVSeenCounter.setText(String.valueOf(modelSingleHotTrendingNewsX.getSeencounter()));
    singleHotTrendingNewsViewHolder.TVCommentCounter.setText(String.valueOf(modelSingleHotTrendingNewsX.getcommentcounter()));
    singleHotTrendingNewsViewHolder.TVLikeCounter.setText(String.valueOf(modelSingleHotTrendingNewsX.getLikecounter()));

    if(modelSingleHotTrendingNewsX.getIscomment() == 0){
        singleHotTrendingNewsViewHolder.IMGCommentView.setImageResource(R.drawable.comment_off);
    }else if(modelSingleHotTrendingNewsX.getIscomment() == 1){
        singleHotTrendingNewsViewHolder.IMGCommentView.setImageResource(R.drawable.comment_on);
    }

    if(modelSingleHotTrendingNewsX.getIslike() == 0){
        singleHotTrendingNewsViewHolder.IMGLikeView.setImageResource(R.drawable.heart_off);
    }else if(modelSingleHotTrendingNewsX.getIslike() == 1){
        singleHotTrendingNewsViewHolder.IMGLikeView.setImageResource(R.drawable.heart_on);
    }

    if(modelSingleHotTrendingNewsX.getTrendingnewssaving() == 0) {
        singleHotTrendingNewsViewHolder.ICONHotTrendingNewsSaving.setImageResource(R.drawable.saved_off);
        singleHotTrendingNewsViewHolder.ICONHotTrendingNewsSaving.setVisibility(View.GONE);
    }else if(modelSingleHotTrendingNewsX.getTrendingnewssaving() == 1) {
        singleHotTrendingNewsViewHolder.ICONHotTrendingNewsSaving.setImageResource(R.drawable.saved_on);
    }

    singleHotTrendingNewsViewHolder.ICONHotTrendingNewsSaving.setOnClicklistener(new View.OnClicklistener() {
        @Override
        public void onClick(View v) {

            final int booltrendingnewssaving = modelSingleHotTrendingNewsX.getTrendingnewssaving();

            final String idcontent = modelSingleHotTrendingNewsX.getIdcontent();

            if (booltrendingnewssaving == 1){
                Toast.makeText(v.getcontext(),"Turn Off Saved News " + idcontent,Toast.LENGTH_SHORT).show();
                singleHotTrendingNewsViewHolder.ICONHotTrendingNewsSaving.setImageResource(R.drawable.saved_off);
                modelSingleHotTrendingNewsX.setTrendingnewssaving(0);
                /*updateSavedNewsSaving("update_newssaving",id,false);*/
            } else if(booltrendingnewssaving == 0) {
                Toast.makeText(v.getcontext(),"Turn On Saved News " + idcontent,Toast.LENGTH_SHORT).show();
                singleHotTrendingNewsViewHolder.ICONHotTrendingNewsSaving.setImageResource(R.drawable.saved_on);
                modelSingleHotTrendingNewsX.setTrendingnewssaving(1);
                /*updateSavedNewsSaving("update_newssaving",true);*/
            }
        }
    });



   /* Glide.with(mContext)
            .load(feedItem.getImageURL())
            .diskCacheStrategy(DiskCacheStrategy.ALL)
            .centerCrop()
            .error(R.drawable.bg)
            .into(feedListRowHolder.thumbView);*/

    /*singleHotTrendingNewsViewHolder.ROWHotTrendingNewsContainer.setOnClicklistener(new View.OnClicklistener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(v.getcontext(),modelSingleHotTrendingNews.get(position).getGamedescription(),Toast.LENGTH_SHORT).show();

            //Passing Data to GameDescriptionactivity
            Intent intent = new Intent(mContext,GameDetailactivity.class);
            intent.putExtra("ImagePKG",modelSingleHotTrendingNews.get(position).getGameimage());
            intent.putExtra("NamePKG",modelSingleHotTrendingNews.get(position).getGamedate());
            intent.putExtra("UrlPKG",modelSingleHotTrendingNews.get(position).getIdcontent());
            intent.putExtra("DescriptionPKG",modelSingleHotTrendingNews.get(position).getGametitle());
            mContext.startactivity(intent);
        }
    });*/
}

@Override
public int getItemCount() {
    int itemCount = modelSingleHotTrendingNews.size();
    return itemCount;
}

public class SingleHotTrendingNewsViewHolder extends RecyclerView.ViewHolder implements View.OnClicklistener{
    TextView TVGameDate;
    TextView TVGameTitle;
    ImageView IMGGameImage;

    TextView TVSeenCounter;
    TextView TVCommentCounter;
    TextView TVLikeCounter;

    ImageView IMGSeenView;
    ImageView IMGCommentView;
    ImageView IMGLikeView;

    ImageView ICONHotTrendingNewsSaving;
    private RelativeLayout ROWHotTrendingNewsContainer;

    private RecyclerViewClicklistener mListener;


    public SingleHotTrendingNewsViewHolder(View itemView,RecyclerViewClicklistener listener) {
        super(itemView);

        TVGameDate = itemView.findViewById(R.id.TV_GameDate);
        TVGameTitle = itemView.findViewById(R.id.TV_GameTitle);
        IMGGameImage = itemView.findViewById(R.id.IMG_GameImage);

        TVSeenCounter = itemView.findViewById(R.id.TV_SeenCounter);
        TVCommentCounter = itemView.findViewById(R.id.TV_CommentCounter);
        TVLikeCounter = itemView.findViewById(R.id.TV_LikeCounter);

        IMGSeenView = itemView.findViewById(R.id.IMG_SeenView);
        IMGCommentView = itemView.findViewById(R.id.IMG_CommentView);
        IMGLikeView = itemView.findViewById(R.id.IMG_LikeView);

        ICONHotTrendingNewsSaving = itemView.findViewById(R.id.ICON_HotTrendingNewsSaving);
        ROWHotTrendingNewsContainer = itemView.findViewById(R.id.ROW_HotTrendingNewsContainer);

        mListener = listener;
        ROWHotTrendingNewsContainer.setOnClicklistener(this);
        IMGCommentView.setOnClicklistener(this);
        IMGLikeView.setOnClicklistener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.ROW_HotTrendingNewsContainer:
                mListener.onRowHotTrendingNewsContainerClick(ROWHotTrendingNewsContainer,getadapterPosition());
                break;
            case R.id.IMG_CommentView:
                mListener.onRowCommentViewClick(IMGCommentView,getadapterPosition());
                break;
            case R.id.IMG_LikeView:
                mListener.onRowLikeViewClick(IMGLikeView,getadapterPosition());
                break;
            default:
                break;
        }
    }
}

public interface RecyclerViewClicklistener {
    void onRowHotTrendingNewsContainerClick(View view,int position);
    void onRowCommentViewClick(View view,int position);
    void onRowLikeViewClick(View view,int position);
}

}

这是HotSectionmodel.java 

public class ModelSectionHotTrendingNews implements Serializable {

private String headerTitle;
private ArrayList<ModelSingleHotTrendingNews> allItemsInSection;

public ModelSectionHotTrendingNews() {
}

public String getHeaderTitle() {
    return headerTitle;
}

public void setHeaderTitle(String headerTitle) {
    this.headerTitle = headerTitle;
}

public ArrayList<ModelSingleHotTrendingNews> getallItemsInSection() {
    return allItemsInSection;
}

public void setallItemsInSection(ArrayList<ModelSingleHotTrendingNews> allItemsInSection) {
    this.allItemsInSection = allItemsInSection;
}

}

这是HotSingleModel.java 

public class ModelSingleHotTrendingNews implements Serializable {

private String idcontent;
private String gametitle;

private String gamedate;
private String gameimage;
private String gamedescription;

private int seencounter;
private int commentcounter;
private int likecounter;

private int iscomment;
private int islike;
private int trendingnewssaving;

private String value;
private String message;

public ModelSingleHotTrendingNews(String idcontent,String gametitle,String gamedate,String gameimage,String gamedescription,int seencounter,int commentcounter,int likecounter,int iscomment,int islike,int trendingnewssaving,String value,String message) {
    this.idcontent = idcontent;
    this.gametitle = gametitle;
    this.gamedate = gamedate;
    this.gameimage = gameimage;
    this.gamedescription = gamedescription;
    this.seencounter = seencounter;
    this.commentcounter = commentcounter;
    this.likecounter = likecounter;
    this.iscomment = iscomment;
    this.islike = islike;
    this.trendingnewssaving = trendingnewssaving;
    this.value = value;
    this.message = message;
}

public String getIdcontent() {
    return idcontent;
}

public void setIdcontent(String idcontent) {
    this.idcontent = idcontent;
}

public String getGametitle() {
    return gametitle;
}

public void setGametitle(String gametitle) {
    this.gametitle = gametitle;
}

public String getGamedate() {
    return gamedate;
}

public void setGamedate(String gamedate) {
    this.gamedate = gamedate;
}

public String getGameimage() {
    return gameimage;
}

public void setGameimage(String gameimage) {
    this.gameimage = gameimage;
}

public String getGamedescription() {
    return gamedescription;
}

public void setGamedescription(String gamedescription) {
    this.gamedescription = gamedescription;
}

public int getSeencounter() {
    return seencounter;
}

public void setSeencounter(int seencounter) {
    this.seencounter = seencounter;
}

public int getcommentcounter() {
    return commentcounter;
}

public void setCommentcounter(int commentcounter) {
    this.commentcounter = commentcounter;
}

public int getLikecounter() {
    return likecounter;
}

public void setLikecounter(int likecounter) {
    this.likecounter = likecounter;
}

public int getIscomment() {
    return iscomment;
}

public void setIscomment(int iscomment) {
    this.iscomment = iscomment;
}

public int getIslike() {
    return islike;
}

public void setIslike(int islike) {
    this.islike = islike;
}

public int getTrendingnewssaving() {
    return trendingnewssaving;
}

public void setTrendingnewssaving(int trendingnewssaving) {
    this.trendingnewssaving = trendingnewssaving;
}

public String getvalue() {
    return value;
}

public void setvalue(String value) {
    this.value = value;
}

public String getMessage() {
    return message;
}

public void setMessage(String message) {
    this.message = message;
}

}

xiaofeiyaya 回答：如何使用LiveData更新RecyclerView示例：SeenCounter，CommentCounter，LikeCounter

因此，您在MainActivity中具有一个响应事件（带有EventBus），在该位置将元素（从api返回的元素）添加到列表中，然后再使用notifyDataSetChanged刷新适配器。

您有两个适配器，因此在您的mainActivity中，您需要该适配器的一个实例，您希望使用该实例刷新数据。

adapter.setItems(list); 
adapter.notifyDataSetChanged();

您也可以在单击like时将新元素添加到列表中，但是比起您如果有一些数据库错误，您的列表将刷新，但是您将与数据库不同步，因此最好使用Evenbus响应。

androidandroid-livedataandroid-recyclerviewjava
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