Question

我不希望更新回收者视图列表中的第一项。我每x秒检索所有元素的一些数据，但我想保持第一项始终相同。

有关如何执行操作的任何线索？

编辑

*fragment*
viewModel.onGetFees.observe(this, Observer<FeesResponse> {
            if (it != null) {
                adapter.setFees(it)
            }
        })

*adapter*
  fun setFees(feesResponse: FeesResponse) {
        this.feesList = AppUtils.toFeesList(feesResponse)
        this.notifyDataSetChanged()
    }



 override fun onBindViewHolder(holder: FeesViewHolder, position: Int) {
        this.context = holder.itemView.context

        holder.tvTitle.text = feesList[position].title
        holder.tvSubtitle.text =
            context.resources.getString(AppUtils.getName(feesList[position].title))

        holder.etFee.setText(feesList[position].rating.toString())

        if (position == 0) {
            holder.etFee.addTextChangedListener(onTextChangedListener)
        }

        Glide.with(holder.ivFlag.context).load(AppUtils.getFlag(feesList[position].countryCode))
            .apply(
                RequestOptions.circleCropTransform()
            ).into(holder.ivFlag)
    }

Answer 1

这取决于您如何更新recyclerview ？。这是你可能理解的我的例子。

 override fun onBindViewHolder(holder: ViewHolder, position: Int) {
if(position==0) //this is for only 1st item  
{
    if(holder.itemView.tag.equal(0)==false) // initially itemview tag will be null . this heppen only for 1st time
    {       
        holder.itemView.tag=position //then assign the value to tag
        //SET YOUR CONTENT HERE
    }
}

}

Answer 2

根据您的要求使用viewType尝试以下代码行

创建CustomPojo.class

    public class CustomPojo{
         public String title;
         public String name;
         public boolean isNeedUpdate;

         public String getTitle() {
             return title;
         }

         public void setTitle(String title) {
             this.title = title;
         }

         public String getName() {
             return name;
         }

         public void setName(String name) {
             this.name = name;
         }

         public boolean isNeedUpdate() {
             return isNeedUpdate;
         }

         public void setNeedUpdate(boolean needUpdate) {
             isNeedUpdate = needUpdate;
         } 
   }

在“活动”或“片段”中的recyclerview处写下以下代码

ArrayList listItem = new ArrayList（）;

public void setAdapter(){

    CustomPojo customPojoNoUpdate = new CustomPojo();
    customPojoNoUpdate.setTitle("xyz");
    customPojoNoUpdate.setName("xyz");
    customPojoNoUpdate.setNeedUpdate(false);

    CustomPojo customPojoUpdate = new CustomPojo();
    customPojoUpdate.setTitle("xyz");
    customPojoUpdate.setName("xyz");
    customPojoUpdate.setNeedUpdate(true);

    listItem.add(customPojoNoUpdate);
    listItem.add(customPojoUpdate);
    MyAdapter adapter = new MyAdapter(listItem);
    recyclerview.setAdapter(adapter);
}

编写以下适配器代码

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

public static final int TYPE_NO_UPDATE = 0;
public static final int TYPE_VIEW_UPDATE = 1;
ArrayList<CustomPojo> list;

public MyAdapter(ArrayList<CustomPojo> list) {
    this.list = list;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
    RecyclerView.ViewHolder viewHolder = null;
    LayoutInflater inflater = LayoutInflater.from(viewGroup.getContext());
    switch (viewType) {
        case TYPE_VIEW_UPDATE:
            View v1 = inflater.inflate(R.layout.row_update_view, viewGroup, false);
            viewHolder = new UpdateView(v1);
            break;

        case TYPE_NO_UPDATE:
            View v4 = inflater.inflate(R.layout.row_no_update, viewGroup, false);
            viewHolder = new NoUpdateView(v4);
            break;
    }
    return viewHolder;
}


@Override
public void onBindViewHolder(final RecyclerView.ViewHolder viewHolder, final int position) {
    if (viewHolder == null) {
        return;
    }

    switch (viewHolder.getItemViewType()) {
        case TYPE_VIEW_UPDATE:
            UpdateView vh1 = (UpdateView) viewHolder;
            vh1.title.setText(list.get(position).getTitle());
            vh1.name.setText(list.get(position).getName());
            break;

        case TYPE_NO_UPDATE:
            NoUpdateView vh4 = (NoUpdateView) viewHolder;
            vh4.title.setText(list.get(position).getTitle());
            break;
    }
}

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

@Override
public int getItemViewType(int position) {
    if (list.size() >= 1 && !list.get(position).isNeedUpdate()) {
        return TYPE_VIEW_UPDATE;
    } else {
        return TYPE_NO_UPDATE;
    }
    return -1;
}

class UpdateView extends RecyclerView.ViewHolder {
    TextView title,name;
    public UpdateView(View view) {
        super(view);
        title = view.findViewById(R.id.title);
        name = view.findViewById(R.id.name);
    }
}


class NoUpdateView extends RecyclerView.ViewHolder {
    TextView title;
    public NoUpdateView(final View itemView) {
        super(itemView);
        title = itemView.findViewById(R.id.title);
    }
}}

希望对您有帮助

不更新recyclerview中的第一项

2 个答案: