android - 当我在 Listview 项目 android 中向下滚动时，项目保存的值消失

Question

public class CustomList extends ArrayAdapter<String> {
    private String[] names;

    private Integer[] imageid;
    private Activity context;
    LayoutInflater inflater;
    List<String> categories;
    boolean firstimagevisible = true;
    boolean secondimagevisible = false;

    public CustomList(Activity context, String[] names, Integer[] imageid) {
        super(context, R.layout.list_layout, names);
        this.context = context;
        this.names = names;

        this.imageid = imageid;

        inflater = LayoutInflater.from(context);

    }


    private class ViewHolder {
        TextView textView;
        ImageView imageView;
        TextView price;
        Button previousimage;
        Button nextimage;
        Spinner sppiner;

    }



    @Override
    public int getViewTypeCount() {

        return getCount();
    }

    @Override
    public int getItemViewType(int position) {

        return position;
    }


    @Override
    public int getCount() {
        return super.getCount();
    }

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

    @Override
    public String getItem(int position) {
        return super.getItem(position);
    }

    public View getView(final int position, View view, ViewGroup parent) {
        final ViewHolder holder;
        if (view == null) {
            holder = new ViewHolder();
            view = inflater.inflate(R.layout.list_layout, null);
            //
            holder.textView = (TextView) view.findViewById(R.id.editText);
            holder.imageView = (ImageView) view.findViewById(R.id.list_avatar);
            holder.price = (TextView) view.findViewById(R.id.price);
            holder.previousimage = (Button) view.findViewById(R.id.previousimage);
            holder.nextimage = (Button) view.findViewById(R.id.nextimage);
            holder.sppiner = (Spinner) view.findViewById(R.id.sppiner);


            view.setTag(holder);
        } else {
            holder = (ViewHolder) view.getTag();
        }
        holder.textView.setText(names[position]);
        holder.imageView.setImageResource(imageid[position]);
        categories = new ArrayList<String>();
        for (int i = 1; i <= 20; i++) {

            categories.add(String.valueOf(i));
        }
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(context,
                android.R.layout.simple_spinner_item, categories);
        dataAdapter
                .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        // attaching data adapter to spinner
        holder.sppiner.setAdapter(dataAdapter);


        holder.previousimage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                holder.imageView.setImageResource(R.drawable.pro1);
                holder.previousimage.setVisibility(View.GONE);
                holder.nextimage.setVisibility(View.VISIBLE);

                secondimagevisible = false;
                firstimagevisible = true;
                holder.price.setText(String.valueOf(1 * 22));
            }
        });

        holder.nextimage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                holder.imageView.setImageResource(R.drawable.pro2);
                holder.nextimage.setVisibility(View.GONE);
                holder.previousimage.setVisibility(View.VISIBLE);
                secondimagevisible = true;
                firstimagevisible = false;
                holder.price.setText(String.valueOf(1 * 16));
            }
        });

        holder.sppiner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                String item = adapterView.getItemAtPosition(i).toString();

                int Quantity = Integer.parseInt(item);
                holder.previousimage.setVisibility(View.GONE);
                if (firstimagevisible == false && secondimagevisible == true) {
                    holder.price.setText(String.valueOf(Quantity * 16));
                } else {
                    holder.price.setText(String.valueOf(Quantity * 22));
                }
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });


        return view;
    }
}

这是我的代码。我在 ListView 中显示 10 个项目。每个在 ImageView 上都有文本和图像。我已经放置了下一个和上一个图像和图像更改，就像我们设置第一个项目 pic1 和第二个项目我点击下一个按钮并将图像更改为 pic2 现在我向下滚动到第 10 个项目，现在再次返回到第一个项目和第二个项目show pic one and next and previous button also disappear while its should save first item pic1 and second item pic2 请告诉我哪里做错了

Answer 1

问题是由缓存引起的，所以我建议在将图像分配给 ImageView 对象之前使用以下代码

            holder.imageView.setDrawingCacheEnabled(false);
            holder.imageView.destroyDrawingCache();
            holder.imageView.setImageDrawable(null);
            holder.imageView.setImageResource(imageid[position]);