RecyclerView在滚动时弄乱了数据

Posted 2021-05-04

滚动向下和向上滚动RecyclerView时遇到问题。这个想法是改变元素的颜色，但是当我向下滚动时，一切都很棒，当滚动向上时 - 不应该着色的元素会改变颜色。

这是我的适配器：

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

private NotificationData notificationData;
private Context mContext;
private ArrayList<NotificationData> infromationList = new ArrayList<>();


public NotificationsAdapter(Context context, ArrayList<NotificationData> infromationList) {
    this.infromationList = infromationList;
    this.mContext = context;
}


@Override
public NotificationsAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    View itemLayoutView;
    ViewHolder viewHolder;

    itemLayoutView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.notification_single_item, parent, false);
    viewHolder = new ViewHolder(itemLayoutView, viewType);

    return viewHolder;
}

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

    notificationData = infromationList.get(position);
    holder.notificationDate.setText(convertDate(notificationData.getDate()));
    holder.notificationStatus.setText(notificationData.getNotificationStatus());
    holder.orderDescription.setText(notificationData.getNotificationLabel());

    if ("true".equals(notificationData.getReadStatus())) {
        holder.root.setBackgroundColor(mContext.getResources().getColor(R.color.white));
        holder.notificationStatus.setTypeface(Typeface.create("sans-serif-light", Typeface.NORMAL));
    }

}

@Override
public int getItemCount() {
    return (null != infromationList ? infromationList.size() : 0);
}

public static class ViewHolder extends RecyclerView.ViewHolder {

    public TextView notificationDate;
    public TextView notificationStatus;
    public TextView orderDescription;
    public LinearLayout root;

    public ViewHolder(View itemView, int position) {
        super(itemView);

        notificationDate = (TextView) itemView.findViewById(R.id.notificationDate);
        notificationStatus = (TextView) itemView.findViewById(R.id.notificationStatus);
        orderDescription = (TextView) itemView.findViewById(R.id.orderDescription);
        root = (LinearLayout) itemView.findViewById(R.id.root);
    }

}

private String convertDate(String date) {
    String convertedDate;

    String[] parts = new String[2];
    parts = date.split("T");
    date = parts[0];

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd");
    Date testDate = null;
    try {
        testDate = sdf.parse(date);
    }catch(Exception ex){
        ex.printStackTrace();
    }
    SimpleDateFormat formatter = new SimpleDateFormat("dd.mm.yyyy");
    convertedDate = formatter.format(testDate);

    return convertedDate;
}
}

答案

我有同样的问题，我找到的唯一解决方案是：

holder.setIsRecyclable(false);

您的回收商将不再回收，因此当您滚动时项目将是相同的，如果您想要删除某些项目不使用notifyitemRemoved(position)，请改用notifyDataSetChanged()。

另一答案

在适配器构造函数中添加setHasStableIds(true);并在适配器中覆盖这两个方法。

@Override
public long getItemId(int position) {
            return position;
}

@Override
public int getItemViewType(int position) {
       return position;
}

另一答案

你的onBindViewHolder(...)有问题，应该是：

if ("true".equals(notificationData.getReadStatus())) {
    holder.root.setBackgroundColor(mContext.getResources().getColor(R.color.white));
    holder.notificationStatus.setTypeface(Typeface.create("sans-serif-light", Typeface.NORMAL));
}
else {
    holder.root.setBackgroundColor(yourDefaultColor);
    holder.notificationStatus.setTypeface(yourDefaultTypeface);

}

另一答案

onBindHolder多次调用，因为Recycler View需要一个视图，除非是新视图。因此，每次在子视图中设置visilibity时，其他视图状态也会发生变化。

无论何时向上和向下滚动，都会使用错误的可见性选项重新绘制这些视图，因此始终指定这两个条件会导致回收器视图不知道我们的小部件的先前状态/条件/值。

方案：

如果在If块中设置任何android widget.setVisibility（View.Gone）的可见性，那么在else块中你必须设置它的可见性相反的值，如widget.setVisibility（View.Visible）来克服上述问题。

 @Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {

    viewHolder.tvName.setText(ModelCategoryProducts.name.get(i));
    viewHolder.tvPrice.setText("Rs."+String.format("%.2f", Float.parseFloat(ModelCategoryProducts.price.get(i))));
    if(ModelCategoryProducts.special_price.get(i).equals("null")) {
        viewHolder.tvSpecialPrice.setVisibility(View.GONE); // here visibility is gone and in else it's opposite visibility i set.
        viewHolder.tvPrice.setTextColor(Color.parseColor("#ff0000"));
        viewHolder.tvPrice.setPaintFlags(0);// here paint flag is 0 and in else it's opposite flag that i want is set.
    }else if(!ModelCategoryProducts.special_price.get(i).equals("null")){
        viewHolder.tvPrice.setTextColor(Color.parseColor("#E0E0E0"));
        viewHolder.tvSpecialPrice.setVisibility(View.VISIBLE);
        viewHolder.tvSpecialPrice.setText("Rs." + String.format("%.2f", Float.parseFloat(ModelCategoryProducts.special_price.get(i))));
        viewHolder.tvPrice.setPaintFlags(viewHolder.tvPrice.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
    }
    if (!ModelCategoryProducts.image_url.get(i).isEmpty()) {
        Picasso.with(context)
                .load(ModelCategoryProducts.image_url.get(i))
                .into(viewHolder.ivProduct);
    }

    viewHolder.setClickListener(new ItemClickListener() {
        @Override
        public void onClick(View view, int position, boolean isLongClick) {
            if (isLongClick) {
//                    Toast.makeText(context, "#" + position + " - " + ModelCategoryProducts.name.get(position) + " (Long click)", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(context, "#" + position + " - " + ModelCategoryProducts.name.get(position), Toast.LENGTH_SHORT).show();
                Intent i = new Intent(context, ProductDetail.class);
                i.putExtra("position",position);
                i.putExtra("flagHlvCheck", 5);
                context.startActivity(i);
            }
        }
    });
}

另一答案

 @Override
public DataObjectHolder onCreateViewHolder(ViewGroup parent,
                                           int viewType) {
    View view = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.custom_layout, parent, false);

    DataObjectHolder dataObjectHolder = new DataObjectHolder(view);
    dataObjectHolder.setIsRecyclable(false);

    return dataObjectHolder;
}

另一答案

最好的方法是指示一个ArrayList，例如作为Model，并有一些参数，并为此定义setter和getter。

package com.test.mohammaddvi.snappfood.Model;

public class OfferList {
private boolean visibilityOrder;
private int number;

public OfferList(int number, boolean visibilityOrder) {
   this.number=number;
   this.visibilityOrder=visibilityOrder;
}

public boolean isVisibilityOrder() {
    return visibilityOrder;
}

public void setVisibilityOrder(boolean visibilityOrder) {
    this.visibilityOrder = visibilityOrder;
}

public int getNumber() {
    return number;
}

public void setNumber(int number) {
    this.number = number;
}

}

并将变量设置为您想要的位置，并且必须在recyclerview适配器的onBindViewHolder中执行此操作：

if (offerList.isVisibilityOrder()) {
        holder.foodMinusButton.setVisibility(View.VISIBLE);
        holder.foodOrderNumber.setText(offerList.getNumber() + "");
        holder.foodOrderNumber.setVisibility(View.VISIBLE);
    } else {
        holder.foodMinusButton.setVisibility(View.INVISIBLE);
    }

并指出它是您的recyclerview适配器：

public class RecyclerViewMenuFragmentAdapter extends RecyclerView.Adapter<RecyclerViewMenuFragmentAdapter.SingleItemInMenuFragment> {

private ArrayList<Food> foodList;
private Context mContext;
private List<OfferList> offers;

public RecyclerViewMenuFragmentAdapter(ArrayList<Food> foodList, Context mContext, List<OfferList> offers) {
    this.foodList = foodList;
    this.mContext = mContext;
    this.offers = offers;
}

另一答案

尝试在适配器中添加它。

@Override
public int getItemViewType(int position)
{
    return position;
}