如何在android中增加视图持有者变量的值? [英] How to increment a value on view holder variables in android?

问题描述

我的 Android 应用中有一个 viewholder，我试图在文本字段上设置一个递增的值.我试过如下，

I have a viewholder in my Android app and I tried to set an incremented value on a textfield. I tried it like following,

活动

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if (convertView == null) {
        holder = new Holder();
        LayoutInflater inflater = (LayoutInflater) this.context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.menu_list_item, null);

        holder.textViewItemName = (TextView) convertView.findViewById(R.id.textViewItemName);
        holder.textViewPrice = (TextView) convertView.findViewById(R.id.textViewPrice);
        holder.imageView = (ImageView) convertView.findViewById(R.id.imageViewItem);
        holder.buttonPlus = (ButtonRectangle) convertView.findViewById(R.id.buttonPlus);
        holder.cartQtyTextView = (TextView) convertView.findViewById(R.id.textViewCartQty);
        holder.buttonMinus = (ButtonRectangle) convertView.findViewById(R.id.buttonMinus);
        convertView.setTag(holder);
    } else {
        holder = (Holder) convertView.getTag();
    }
    final MenuItem listItem = objects.get(position);
    holder.textViewItemName.setText(listItem.getItemName());
    holder.textViewPrice.setText("$ ".concat(String.valueOf(listItem.getItemPrice())));

    // Check & Set
    if (holder.buttonPlus != null) {
        holder.buttonPlus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (holder.cartQtyTextView != null) {
                    if (holder.inc >= 0) {
                        holder.cartQtyTextView.setText(String.valueOf(holder.inc++));
                    }
                }
            }
        });
    }
    holder.buttonPlus.setBackgroundColor(Color.WHITE);
    holder.buttonPlus.setTextColor(Color.parseColor("#333333"));

    // Check & Set
    if (holder.buttonMinus != null) {
        holder.buttonMinus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (holder.inc >= 0) {
                    holder.cartQtyTextView.setText(String.valueOf(holder.inc--));
                }
            }
        });
    }
    holder.buttonMinus.setBackgroundColor(Color.WHITE);
    holder.buttonMinus.setTextColor(Color.parseColor("#333333"));

    return convertView;

}

支架

class Holder {
    ButtonRectangle buttonPlus;
    ButtonRectangle buttonMinus;
    TextView cartQtyTextView;
    TextView textViewItemName;
    TextView textViewPrice;
    ImageView imageView;
    int inc;
}

但这是随机递增的.我该如何解决这个问题?

But this is incrementing randomly. How may I fix this?

推荐答案

 > But this is incrementing randomly

这是因为查看者可能属于不同的订单行.

that is because the viewholder may belong to different order-lines.

示例

• 一开始，viewholder#1 属于订单号#1，inc=2
• 如果您向下滚动列表框订单行 #1 将变得不可见而订单行 #27 变得可见..
• 现在订单行 #27 正在重用 viewholder#1 和 inc=2

如何解决这个问题:

您需要一个对象模型来存储数据 inc、articleid、数量、单价、articlename ......

you need an objectmodell that store the data inc, articleid, quantity, unitprice, articlename, ......

 final OrderItem orderItem = (OrderItem) objects.get(position);
 ...
 orderItem.inc++;

另见https://stackoverflow.com/search?q=listview+random

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