Android自定义列表视图，滚动后对象重复ID

Question

我已经获得了基于＆＃34; ORDER MANAGEMENT＆＃34;开发的应用程序，我正在开发此应用程序的最基本任务，即＆＃34;带有ORDER按钮的项目列表，当按钮是单击，出现一个带有项目标题的对话框，要求用户输入要订购的项目数量。＆＃34;现在我列出了哪些任务已经完成。＆＃34; 显示项目列表。 每个项目都包含ORDER BUTTON，点击它以显示dilog。它也有效，Dialog使用Edittext询问数量，在确认对话框操作时我也将edittext的值作为字符串获取并将其保存在变量中。 现在我面临的问题是，当我点击列表视图中的倒数第二个和最后一个项目时，它会分别返回第一个和第二个项目的ID，即1和2. ID＆＃39; s应该是我已分配的内容制作数据主义者。我知道我的适配器有一些问题，但我无法解决它。

这是项目类Item.java

package com.example.learnone;

public class Item {

    private String name,partnumber,description;
    private double price,cost;
    private int id, qtyStart,qtySold,qtyPerPack,qtyordered;

    public Item(){}

    public Item(int id, double price, String name, int qtyordered){
        super();
        this.id = id;
        this.price = price;
        this.name = name;
        this.qtyordered = qtyordered;
    }

    public Item(double price, String name, int qtyordered){
        super();
        this.price = price;
        this.name = name;
        this.qtyordered = qtyordered;
    }   

    public Item(String name){
        super();
        this.name = name;       
    }

    public int getQtyordered() {
        return qtyordered;
    }

    public void setQtyordered(int qtyordered) {
        this.qtyordered = qtyordered;
    }

    public String getName() {
        return name;
    }

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

    public String getPartnumber() {
        return partnumber;
    }

    public void setPartnumber(String partnumber) {
        this.partnumber = partnumber;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public double getCost() {
        return cost;
    }

    public void setCost(double cost) {
        this.cost = cost;
    }

    public int getQtyStart() {
        return qtyStart;
    }

    public void setQtyStart(int qtyStart) {
        this.qtyStart = qtyStart;
    }

    public int getQtySold() {
        return qtySold;
    }

    public void setQtySold(int qtySold) {
        this.qtySold = qtySold;
    }

    public int getQtyPerPack() {
        return qtyPerPack;
    }

    public void setQtyPerPack(int qtyPerPack) {
        this.qtyPerPack = qtyPerPack;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

}

这是AdapterItem.java

public class AdapterItem extends ArrayAdapter<Item> {

    Context context;
    List<Item> itemList;
    int layoutResID;
    int[] quantity;

    public AdapterItem(Context context, int resource,
            List<Item> objects) {
        super(context, resource, objects);
        this.context = context;
        this.itemList = objects;
        this.layoutResID = resource;
    }

    private static class ViewHolder{
        TextView viewItemName,viewItemPrice,viewItemQuantity;
        Button viewQuantityAdder;
        int pos;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View view = convertView;
        final Item item = getItem(position);
        final ViewHolder holder;

        if(convertView == null){
            holder = new ViewHolder();
            final LayoutInflater inflater = ((Activity) context).getLayoutInflater();
            view = inflater.inflate(layoutResID, parent, false);

            holder.viewItemName = (TextView) view.findViewById(R.id.item_name);
            holder.viewItemPrice = (TextView) view.findViewById(R.id.item_price);
            holder.viewItemQuantity = (TextView) view.findViewById(R.id.item_quantity);
            holder.viewQuantityAdder = (Button) view.findViewById(R.id.item_quantity_adder);
            holder.viewQuantityAdder.setOnClickListener(new OnClickListener() {             
                @Override
                public void onClick(View arg0) {
                    //Toast.makeText(getContext(), item.getName().toString(), Toast.LENGTH_SHORT).show();
                    AlertDialog.Builder builder  = new AlertDialog.Builder(getContext());

                    builder.setTitle(item.getName().toString());

                    final View dialogView = View.inflate(getContext(),R.layout.dialog_quantity, null);

                    builder.setView(dialogView)

                   .setPositiveButton("TO CART", new DialogInterface.OnClickListener() {
                       @Override
                       public void onClick(DialogInterface dialog, int id) {
                           EditText newQuantity = (EditText) dialogView.findViewById(R.id.takeQuantity);
                           item.setQtyordered(Integer.parseInt(newQuantity.getText().toString()));
                           Toast.makeText(getContext(), "ID: " + Integer.toString(item.getId()) + " Quantity: " +Integer.parseInt(newQuantity.getText().toString()), Toast.LENGTH_LONG).show();
                           //Toast.makeText(getContext(), Integer.toString(item.getQtyordered()), Toast.LENGTH_SHORT).show();
                           //notifyDataSetChanged();
                       }
                   })

                   .setNeutralButton("RESET", new DialogInterface.OnClickListener() {
                       @Override
                       public void onClick(DialogInterface dialog, int id) {
                       }
                   })

                    .setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
                                   public void onClick(DialogInterface dialog, int id) {
                                   }
                               });  

                    AlertDialog dialog = builder.create();
                    dialog.show();                                  
                }

            });

            view.setTag(holder);
        }else{
            holder = (ViewHolder) view.getTag();
        }


        holder.viewItemName.setText(item.getName());
        holder.viewItemPrice.setText(Integer.toString(item.getId()));
        holder.viewItemQuantity.setText("QUANTITY: " + Integer.toString(item.getQtyordered()));     

        return view;
    }

}

这是一个MainActivity.java

public class MainActivity extends Activity {

    FragmentManager fragmentManager;
    FragmentTransaction fragmentTransaction;
    FragmentItemList fragmentItemList;  

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        fragmentManager = getFragmentManager();
        fragmentTransaction = fragmentManager.beginTransaction();

        fragmentItemList = new FragmentItemList();
        fragmentTransaction.add(R.id.content_frame, fragmentItemList);
        fragmentTransaction.commit();       

    }

    public static class FragmentItemList extends Fragment{

        ProgressBar pb;

        List<Item> dataList;

        public FragmentItemList() {
        }

        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState){

                View rootView = inflater.inflate(R.layout.fragment_items_list, container, false);

                pb = (ProgressBar) rootView.findViewById(R.id.progressBar1);
                pb.setVisibility(ProgressBar.INVISIBLE);

                ListView itemListView = (ListView) rootView.findViewById(R.id.itemListView);

                /*
                List<String> testList = new ArrayList<String>();                                            
                testList.add("Sprocket Kit");
                testList.add("Engine Bolt Kit");

                ArrayAdapter<String> itemsAdapter = 
                        new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, testList);
                itemListView.setAdapter(itemsAdapter);
                */

                dataList = new ArrayList<Item>();

                dataList.add(new Item(1, 40.0, "SPROCKETS BOLTS KIT", 0));
                dataList.add(new Item(2, 190.0, "ENGINE BOLTS KIT", 0));
                dataList.add(new Item(3, 25.0, "ENGINE AXEL KIT", 0));
                dataList.add(new Item(4, 4.0, "LONG CAP SHOW NUT", 0));
                dataList.add(new Item(5, 2.5, "CAP NUT", 0));
                dataList.add(new Item(6, 0.75, "WELD NUTS M6", 0));
                dataList.add(new Item(7, 1.10, "WELD NUTS M8", 0));

                AdapterItem itemsAdapter = 
                        new AdapterItem(getActivity(), R.layout.item_row, dataList);
                itemListView.setAdapter(itemsAdapter);

            return rootView;
        }

    }

}

我正在寻找好的建议和指导。 感谢。