Question

我有列表视图想要在特定行的列表视图中增加和减少产品数量。指导我这样做

public class ProductsAdapter extends BaseAdapter {

    private Context context;
    private ArrayList<HashMap<String, String>> postItems;
    public SharedPreferences settings;
    public final String PREFS_NAME = "Products";

    private MyCart cart;
    private  HashMap<String, String> selected_product;

    DisplayImageOptions options;
    ImageLoaderConfiguration imgconfig;
    private static int _counter = 1;
    private String _stringVal;


    public ProductsAdapter(Context context, ArrayList<HashMap<String, String>> arraylist){
        this.context = context;

        File cacheDir = StorageUtils.getCacheDirectory(context);
        options = new DisplayImageOptions.Builder()
        .showImageOnLoading(R.drawable.loading)
        .showImageForEmptyUri(R.drawable.loading)
        .showImageOnFail(R.drawable.loading)
        .cacheInMemory(true)
        .cacheOnDisk(true)
        .considerExifParams(true)
        .displayer(new SimpleBitmapDisplayer())
        .imageScaleType(ImageScaleType.EXACTLY)
        .build();

        imgconfig = new ImageLoaderConfiguration.Builder(context)
        .build();
        ImageLoader.getInstance().init(imgconfig);

        postItems = arraylist;
        settings = context.getSharedPreferences(PREFS_NAME, 0);

        selected_product = new HashMap<String,String>();

        cart=new MyCart(context.getApplicationContext());

    }

    @Override
    public int getCount() {
        return postItems.size();
    }
    @Override
    public Object getItem(int position) {       
        return postItems.get(position);
    }

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

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

            if (convertView == null) {
                LayoutInflater mInflater = (LayoutInflater)
                context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
                convertView = mInflater.inflate(R.layout.row_products, null);   
            }
            HashMap<String, String> map = postItems.get(position);


            ImageView imgProduct = (ImageView)convertView.findViewById(R.id.proimage);
            ImageLoader.getInstance().displayImage(ConstValue.PRO_IMAGE_BIG_PATH+map.get("image"), imgProduct, options, animateFirstListener);

            TextView txtTitle = (TextView)convertView.findViewById(R.id.proTitle);
            txtTitle.setText(map.get("title"));

            TextView txtPrice = (TextView)convertView.findViewById(R.id.txtprice);
            txtPrice.setText(map.get("price"));

            TextView textDiscount = (TextView)convertView.findViewById(R.id.textDiscount);
            textDiscount.setVisibility(View.GONE);

            TextView txtDiscountFlag = (TextView)convertView.findViewById(R.id.textDiscountFlag);
            txtDiscountFlag.setVisibility(View.GONE);

            TextView textCurrency = (TextView)convertView.findViewById(R.id.textCurrency);
            textCurrency.setText(map.get("currency"));

            final TextView value = (TextView)convertView.findViewById(R.id.textView3);

            final Button txtminus = (Button) convertView.findViewById(R.id.minus);

            txtminus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                    Log.d("src", "Decreasing value...");
                    _counter--;
                    _stringVal = Integer.toString(_counter);
                    value.setText(_stringVal);

                    selected_product = (HashMap<String, String>) postItems.get(position);
                    selected_product.put("qty", _stringVal);
                    cart.remove_to_cart(selected_product);
                }

            });

            Button txtplus  = (Button) convertView.findViewById(R.id.plus);
            txtplus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                    Log.d("src", position + "Increasing value...");
                    Log.d("Position", position + "position");

                    _counter++;
                    _stringVal = Integer.toString(_counter);
                    value.setText(_stringVal);

                    selected_product = (HashMap<String, String>) postItems.get(position);
                    selected_product.put("qty", _stringVal);
                    cart.add_to_cart(selected_product);


            }
            });

public class ProductsAdapter extends BaseAdapter {

Answer 1

您正在进行的当前设置只有一个计数器变量，您需要为每个列表视图行设置一个变量。我建议创建一些将按钮映射到位置值的哈希映射，所以：

private HashMap<Button, Integer> decrementButtons;
private HashMap<Button, Integer> incrementButtons;
private HashMap<Integer, Integer> positionCount;

public view getView(final int position, ....) {
    ... //Stuff above
    decrementButtons.put(txtminus, position);
    incrementButtons.put(txtplus, position);
    if (!positionCount.contains(position)) {
        positionCount.put(position, 0);
    }
}

然后在你的onClick方法中添加：

public void onClick(View v) {
   ...
   Button button = (Button) v;
   int position = decrementButtons.get(button); //Change for increment
   int count = positionCount.get(position);
   count--;
   positionCount.put(position, count);
   ...
}

想要在listview中增加和减少产品数量

1 个答案: