Question

我使用RecyclerView显示项目列表，我需要按位置更新单个项目的状态。我正在更新列表中的项目，然后像这样调用notifyItemChanged(int position)：

myList.set(position, newModifiedItem);
notifyItemChanged(position);

项目已成功更新，但也会随机更新其他项目，每次我在项目列表中向上和向下滚动时，此更新（不同的图标状态）也会在其他项目上进行。

我在onBindViewHolder进行更改，我逐个检查列表，并决定设置不同的状态。

完整适配器代码：

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

    private List<MyObj> myList;

    public MyAdapter(List<MyObj> list) {
        this.myList = list;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_item, parent, false);
        return new ViewHolder(view);
    }

    public void onBindViewHolder(final ViewHolder holder, final int position) {
        MyObj myObj = myList.get(position);
        boolean isSpecial = myObj.getMySpecialStatus();

        holder.myItemTitle.setText(myObj.getTitle());

        //decide if item has different icon state
        if (isSpecial) {
            holder.myItemIcon.setImageResource(R.drawable.ic_special);    
        } 
    }

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


    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        public TextView myItemTitle;
        public ImageView myItemIcon;
        public LinearLayout itemClickable;
        //some other views

        public ViewHolder(View itemView) {
            super(itemView);
            myItemTitle = (TextView) itemView.findViewById(R.id.item_title);
            myItemIcon = (ImageView) itemView.findViewById(R.id.item_img);

            itemClickable = (LinearLayout) itemView.findViewById(R.id.item_clickable_zone);
            itemClickable.setOnClickListener(this);

            //some other views
        }

        @Override
        public void onClick(View v) {
            final int position = getAdapterPosition();
            if (position != RecyclerView.NO_POSITION) {

                switch (v.getId()) {
                    case R.id.item_clickable_zone: {

                        //some logic to change status - here just an idea
                        MyObj newModifiedItem = myList.get(position);
                        newModifiedItem.setMySpecialStatus(true);

                        myList.set(position, newModifiedItem);
                        notifyItemChanged(position);
                        break;
                    }

                    //some other views on click
                }
            }
        }
    }
}

Answer 1

问题发生在onBindViewHolder()，您没有对else语句使用if个案。它应该像：

public void onBindViewHolder(final ViewHolder holder, final int position) {
        MyObj myObj = myList.get(position);
        boolean isSpecial = myObj.getMySpecialStatus();

        holder.myItemTitle.setText(myObj.getTitle());

        //decide if item has different icon state
        if (isSpecial) {
            holder.myItemIcon.setImageResource(R.drawable.ic_special);    

         } else {
            //here is the trick - set normal state back
            holder.myItemIcon.setImageResource(R.drawable.ic_standard);
         }
    }

Answer 2

试试这个，

MyObj newModifiedItem = myList.get(position); //getting object from the list
newModifiedItem.setMySpecialStatus(true);
notifyItemChanged(position, newModifiedItem);

notifyItemChanged（int position）更新RecyclerView

2 个答案: