从片段更新ListView适配器内的TextView

Question

我在我的TextView有一个价格OrderFragment，我想更新onItemSelected每个项目的折扣和每个票据Spinner折扣。一旦我改变了我的物品的价格，我尝试在我的notifyDataSetChanged上使用ArrayList，但它没有更新我的ListView。 notifyDataSetChanged工作正常，当我在不同的片段中使用它来添加和删除我的ArrayList元素，但更新价格在ArrayList这似乎不起作用。

为了更新我的每个帐单的折扣，我提到了各种问题，但它似乎没有得到它的工作：notifyDataSetChange not working from custom adapter，Android: notifyDataSetChanged(); not working，Android ListView not refreshing after notifyDataSetChanged和其他人也。然后我尝试使用TextView从我的Fragment更改ListView.getChildAt()但由于ListView仅加载可见行而无法正常工作，因此，其他不可见的行不会更新。

至于每个项目的折扣，我有它的工作，但使用2 Callback似乎效率不高。

OrderFragment

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);
    }
}
}

ListViewOrderAdapter

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

    }
}
}

P / S：请先忽略计算以获得折扣价，因为它确实与我的两个折扣微调器冲突（最初我只实现了每件商品的折扣）。

这是我的应用程序的屏幕截图：See here

Answer 1

您正在使用适配器中的订单列表但是在计算折扣后是否更新了订单列表？

如果你没有按顺序更新数据List，notifyDataSetChanged并没有真正做任何事情。

希望有所帮助。