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Question

我的TextView中有OrderFragment的价格，我想更新onItemSelected每件商品的折扣和每个帐单的折扣Spinner。我曾在我的notifyDataSetChanged上尝试使用ArrayList，但我更改了我的商品价格，但没有更新我的ListView。当我在不同的片段中使用notifyDataSetChanged添加和删除ArrayList中的元素时，ArrayList工作正常，但TextView上的更新价格似乎不起作用。

为了更新我的每个帐单的折扣，我提到了各种问题，但它似乎无法正常运行：notifyDataSetChange not working from custom adapter，Android: notifyDataSetChanged(); not working，Android ListView not refreshing after notifyDataSetChanged以及其他问题。然后我尝试使用Fragment从ListView.getChildAt()更改ListView，但由于Callback仅加载可见行，因此其他行不可见，因此无效没有更新。

至于每个项目的折扣，我让它工作但是使用2 public class OrderFragment extends Fragment { private ArrayList<Product> orderList = new ArrayList<Product>(); private ListView lvConfirmOrder; private ListViewOrderAdapter lvConfirmOrderAdapter; private TextView tvTotalOrderPrice; private int totalOrderPrice; private Spinner sBillDiscount; private int billDiscount = 0; private ItemClickListener itemClickListener; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment view = inflater.inflate(R.layout.fragment_order, container, false); activity = getActivity(); db = DatabaseHelper.getInstance(activity); Bundle bundle = new Bundle(); orderList = getArguments().getParcelableArrayList("orderList"); tvTotalOrderPrice = (TextView) view.findViewById(R.id.tvShowTotalPrice); sBillDiscount = (Spinner) view.findViewById(R.id.sBillDiscount); lvConfirmOrder = (ListView) view.findViewById(R.id.lvConfirmOrder); lvConfirmOrderAdapter = new ListViewOrderAdapter(activity, orderList, new ItemClickListener() { @Override public void onItemClick(Product product) { } @Override public void onItemClick(ProductCategory productCategory) { } @Override public void onItemClick(ArrayList<Product> productList) { tvTotalOrderPrice.setText(String.format("%d",setTotalPrice())); } }); lvConfirmOrder.setAdapter(lvConfirmOrderAdapter); // Get the total price of all items totalOrderPrice = setTotalPrice(); // Set the total price into TextView tvTotalOrderPrice.setText(String.format("%d",totalOrderPrice)); addItemsOnSBillDiscountAndPreselect(billDiscount); sBillDiscount.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { float spinnerValue = Float.parseFloat(adapterView.getItemAtPosition(i).toString()); float discount = 1.0f - (spinnerValue/100.0f); totalAfterDiscount(discount); } @Override public void onNothingSelected(AdapterView<?> adapterView) { } }); return view; } private int setTotalPrice() { int totalPrice = 0; for (int index = 0; index < orderList.size(); index++) { totalPrice += orderList.get(index).getOrderPrice(); } return totalPrice; } // add items into spinner public void addItemsOnSBillDiscountAndPreselect(int discount) { List<Integer> list = new ArrayList<Integer>(); for(int index = 0; index <= 100; index++) { list.add(index); } ArrayAdapter<Integer> dataAdapter = new ArrayAdapter<Integer>(activity, android.R.layout.simple_spinner_item, list); dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); sBillDiscount.setAdapter(dataAdapter); int spinnerPosition = dataAdapter.getPosition(discount); sBillDiscount.setSelection(spinnerPosition); } public void totalAfterDiscount(float discount) { float totalItemPrice[] = new float[orderList.size()]; for (int i = 0; i < orderList.size(); i++) { totalItemPrice[i] = orderList.get(i).getOrderPrice() * discount; } TextView tvPrice; for ( int i = 0 ; i < lvConfirmOrder.getCount() ; i++){ View v = getViewByPosition(i,lvConfirmOrder); tvPrice = (TextView) v.findViewById(R.id.tvQtyPrice); tvPrice.setText(String.valueOf(totalItemPrice[i])); } tvTotalOrderPrice.setText(String.format("%d",setTotalPrice())); lvConfirmOrderAdapter.notifyDataSetChanged(); } public View getViewByPosition(int position, ListView listView) { final int firstListItemPosition = listView.getFirstVisiblePosition(); final int lastListItemPosition =firstListItemPosition + listView.getChildCount() - 1; if (position < firstListItemPosition || position > lastListItemPosition ) { return listView.getAdapter().getView(position, listView.getChildAt(position), listView); } else { final int childIndex = position - firstListItemPosition; return listView.getChildAt(childIndex); } } } 似乎效率不高。

OrderFragment

public class ListViewOrderAdapter extends ArrayAdapter {
//to store the list of products
private ArrayList<Product> productList = new ArrayList<Product>();

private ItemClickListener itemClickListener;
private ViewHolder viewHolder;
private DiscountSpinnerListener discountSpinnerListener;

private static class ViewHolder {
    TextView tvProductName;
    TextView tvProductSku;
    TextView tvPrice;
    TextView tvProductNum;
    TextView iAddQuantity;
    TextView tvQuantity;
    TextView tvQtyPrice;
    TextView iMinusQuantity;
    Spinner sDiscount;
    TextView iDelete;
}

public ListViewOrderAdapter(Activity context, ArrayList<Product> listProduct, ItemClickListener itemClickListener){

    super(context,R.layout.row_order , listProduct);
    this.context = context;
    this.productList = listProduct;
    this.itemClickListener = itemClickListener;

}

public View getView(final int position, View view, ViewGroup parent) {
    final Product product = productList.get(position);

    if (view == null) {
        // If there's no view to re-use, inflate a brand new view for row
        viewHolder = new ViewHolder();
        LayoutInflater inflater = LayoutInflater.from(context);
        view = inflater.inflate(R.layout.row_order, null, false);
        viewHolder.tvProductName = (TextView) view.findViewById(R.id.tvOrderProduct);
        viewHolder.tvProductSku = (TextView) view.findViewById(R.id.tvOrderSKU);
        viewHolder.tvPrice = (TextView) view.findViewById(R.id.tvProductPrice);
        viewHolder.tvProductNum = (TextView) view.findViewById(R.id.tvOrderNum);
        viewHolder.iAddQuantity = (TextView) view.findViewById(R.id.iAddQuantity);
        viewHolder.tvQuantity = (TextView) view.findViewById(R.id.tvQuantity);
        viewHolder.tvQtyPrice = (TextView) view.findViewById(R.id.tvQtyPrice);
        viewHolder.iMinusQuantity = (TextView) view.findViewById(R.id.iMinusQuantity);
        viewHolder.sDiscount = (Spinner) view.findViewById(R.id.sDiscount);
        viewHolder.iDelete = (TextView) view.findViewById(R.id.iDelete);

        // Cache the viewHolder object inside the fresh view
        view.setTag(viewHolder);
    } else {
        // View is being recycled, retrieve the viewHolder object from tag
        viewHolder = (ViewHolder) view.getTag();
    }

    //this code sets the values of the objects to values from the arrays
    viewHolder.tvProductName.setText(product.getProduct_name());
    viewHolder.tvProductSku.setText(product.getProduct_sku());
    viewHolder.tvPrice.setText(String.valueOf(product.getPrice_max()));
    String num = Integer.toString(position + 1);
    viewHolder.tvProductNum.setText(num);
    viewHolder.tvQuantity.setText(String.valueOf(product.getOrderQuantity()));
    addItemsOnSDiscountAndPreselect(viewHolder,product.getDiscount_per_item());

    viewHolder.sDiscount.setOnItemSelectedListener(new SpinnerListener(viewHolder, position, new DiscountSpinnerListener() {
        @Override
        public void onDiscountChange(TextView tvPrice, int pos, float price) {
            if (position == pos) {
                tvPrice.setText(String.valueOf(price));
                itemClickListener.onItemClick(productList);
            }
        }
    }));

    font = Typeface.createFromAsset(context.getAssets(), "fonts/fontawesome-webfont.ttf" );
    viewHolder.iAddQuantity.setTypeface(font);
    viewHolder.iMinusQuantity.setTypeface(font);
    viewHolder.iDelete.setTypeface(font);

    viewHolder.iAddQuantity.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            product.setOrderQuantity(product.getOrderQuantity() + 1);
            product.setOrderPrice(product.getOrderQuantity() * product.getPrice_max());
            itemClickListener.onItemClick(productList);
            notifyDataSetChanged();
        }
    });

    viewHolder.iMinusQuantity.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            product.setOrderQuantity(product.getOrderQuantity() - 1);
            product.setOrderPrice(product.getOrderQuantity() * product.getPrice_max());
            if (product.getOrderQuantity() == 0) {
                createAndShowAlertDialog(position, productList);
            } else {
                itemClickListener.onItemClick(productList);
                notifyDataSetChanged();
            }
        }
    });

    viewHolder.iDelete.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            createAndShowAlertDialog(position, productList);
            notifyDataSetChanged();
        }
    });

    return view;

}

private void createAndShowAlertDialog(final int position, final ArrayList<Product> productList) {
    AlertDialog.Builder builder = new AlertDialog.Builder(context,R.style.MyDialogTheme);
    builder.setTitle("Are you sure you want to delete " + productList.get(position).getProduct_name());
    builder.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            productList.remove(position);
            itemClickListener.onItemClick(productList);
            notifyDataSetChanged();
            dialog.dismiss();
        }
    });
    builder.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            productList.get(position).setOrderQuantity(1);
            dialog.dismiss();
        }
    });
    AlertDialog dialog = builder.create();
    dialog.setCancelable(false);
    dialog.setCanceledOnTouchOutside(false);
    dialog.show();
}

// add items into spinner
public void addItemsOnSDiscountAndPreselect(ViewHolder viewHolder, int discount) {
    List<Integer> list = new ArrayList<Integer>();
    for(int index = 0; index <= 100; index++) {
        list.add(index);
    }
    ArrayAdapter<Integer> dataAdapter = new ArrayAdapter<Integer>(context,
            android.R.layout.simple_spinner_item, list);
    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    viewHolder.sDiscount.setAdapter(dataAdapter);

    int spinnerPosition = dataAdapter.getPosition(discount);
    viewHolder.sDiscount.setSelection(spinnerPosition);
}

private class SpinnerListener implements AdapterView.OnItemSelectedListener {

    private int mSpinnerPosition;
    private DiscountSpinnerListener discountSpinnerListener;
    private ViewHolder viewHolder;

    public SpinnerListener(ViewHolder viewHolder, int spinnerPosition, DiscountSpinnerListener discountSpinnerListener) {
        mSpinnerPosition = spinnerPosition;
        this.discountSpinnerListener = discountSpinnerListener;
        this.viewHolder = viewHolder;
    }

    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        float spinnerValue = Float.parseFloat(arg0.getItemAtPosition(arg2).toString());
        float discount = 1.0f - (spinnerValue/100.0f);
        float totalItemPrice = productList.get(mSpinnerPosition).getPrice_max() * productList.get(mSpinnerPosition).getOrderQuantity() * discount;
        productList.get(mSpinnerPosition).setOrderPrice(totalItemPrice);
        productList.get(mSpinnerPosition).setDiscount_per_item(Integer.parseInt(arg0.getItemAtPosition(arg2).toString()));

        // Listener to set total price of an item after discount
        discountSpinnerListener.onDiscountChange(viewHolder.tvQtyPrice, mSpinnerPosition, totalItemPrice);
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }
}
}

ListViewOrderAdapter

ast.literal_eval

P / S：请先忽略计算以获得折扣价，因为它与我的两个折扣微调器都存在冲突（最初我只是为每件商品实施折扣）。

这是我的应用的屏幕截图：See here

Answer 1

您在适配器中使用orderList但是在计算折扣后是否更新了orderList？

如果你不在orderList中更新数据，notifyDataSetChangeddoesnt真的可以做任何事情。

希望有所帮助。