在自定义列表视图中显示来自 TextView 值的总量

Question

我的应用中有一个购物车，我一直想知道如何从列表视图中的文本视图中获取值的总和，然后将其显示在另一个类中？

那个orderTotal数组就是每行产品的数量

这是我的适配器类：

public class ListCartAdapter extends BaseAdapter {


private Context context;


private ArrayList<String> orderTotal;

public ListCartAdapter(Context context, ArrayList<String> orderTotal){
    this.context = context;
    this.orderTotal = orderTotal;
}

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

@Override
public Object getItem(int position) {
    return orderName.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}

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

  final cartDatabaseHelper db = new cartDatabaseHelper(context);

    final View listView;
    final LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    listView = inflater.inflate(R.layout.cart_list_item, null);

  TextView total = (TextView) listView.findViewById(R.id.textOrderTotal);

    total.setText(orderTotal.get(position));

    return listView;
}

这是 MainActivity 类：

//CART LISTVIEW
private ArrayList<String> orderid;
private ArrayList<String> orderName;
private ArrayList<String> orderSize;
private ArrayList<String> orderQuantity;
private ArrayList<String> orderTotal;

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

    //CART LISTVIEW
    orderid = new ArrayList<>();
    orderName = new ArrayList<>();
    orderSize = new ArrayList<>();
    orderQuantity = new ArrayList<>();
    orderTotal = new ArrayList<>();

    TextView textTotal = (TextView) findViewById(R.id.textOrderSumTotal);

    ListView listView = (ListView) findViewById(R.id.listView);

    ListCartAdapter adapter = new ListCartAdapter(cart.this, orderid, orderName, orderSize, orderQuantity, orderTotal);
    listView.setAdapter(adapter);

    Cursor data = db.getListContents();

    if(data.getCount() == 0){
        btnCheckout.setVisibility(View.GONE);
    }
    else
    {
        btnCheckout.setVisibility(View.VISIBLE);

        data.moveToFirst();
        do{
            orderid.add(data.getString(0));
            orderName.add(data.getString(1));
            orderSize.add(data.getString(2));
            orderQuantity.add(data.getString(3));
            orderTotal.add(data.getString(4));
        } while (data.moveToNext());
    }
    data.close();

    listView.setEmptyView(findViewById(R.id.emptyView));

}

textTotal 是我计划显示列表视图中值的总和的地方。

谁能指出我正确的方向？提前致谢！

Answer 1

如果您已将所有价格列在名为orderTotal 的数组列表中，这很简单。遍历列表并添加所有值，如下所示：

int total = 0;
for(String s : orderTotal){
   total += Integer.parseInt(s);
}

在任何你想要的地方显示这个total。如果价格是浮动的，则使用Float.parseFloat(YOUR_FLOAT_STRING);