Question

我有一个使用sqlite的应用程序，它存储有关硬件商店项目的信息并在ListView中显示它们，此列表视图显示项目的名称，价格，数量和供应商。每个列表项也有一个Sell按钮，当我点击按钮时，它应该从该特定项的数量中减去1并更新数据库，但由于该按钮是在CursorAdapter中创建的，我不知道如何访问数据库并更新它

这是我的CursorAdapter：

package com.example.android.inventoryapp;

import android.content.Context;
import android.database.Cursor;
import android.support.v4.widget.CursorAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.android.inventoryapp.data.InventoryContract.InventoryEntry;


public class InventoryCursorAdapter extends CursorAdapter {


    public InventoryCursorAdapter(Context context, Cursor cursor) {
        super(context, cursor, 0);
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        return LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {

        TextView itemNameView = view.findViewById(R.id.item_name);
        TextView itemPriceView = view.findViewById(R.id.item_price);
        TextView itemQuantityView = view.findViewById(R.id.item_quantity);
        TextView itemSupplierView = view.findViewById(R.id.item_supplier);

        ImageView sellButton = view.findViewById(R.id.sell_button);

        int nameColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_ITEM_NAME);
        int priceColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_ITEM_PRICE);
        int quantityColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_ITEM_QUANTITY);
        int supplierColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_ITEM_SUPPLIER);

        int quantity = cursor.getInt(quantityColumnIndex);

        String name = cursor.getString(nameColumnIndex);
        String price = String.valueOf(cursor.getInt(priceColumnIndex)) + context.getString(R.string.currency_symbol);
        String quantityStr = String.valueOf(quantity);
        String supplier = cursor.getString(supplierColumnIndex);

        itemNameView.setText(name);
        itemPriceView.setText(price);
        itemQuantityView.setText(quantityStr);
        itemSupplierView.setText(supplier);

    }

}

Answer 1

在包含适配器引用的活动中，创建一个内部类，如：

parms[0] = new object[] { "foo" };

然后在创建适配器时

  public class MyClickListener {
    public void handleClick(Item item) {
      // access your DB here, {item} is available if you need the data
    }
  }

在适配器中保存对该单击侦听器的引用。

然后在适配器的BindView方法中（如果你需要项目数据来更新数据库，将它传递给点击监听器）

myAdapter = new InventoryCursorAdapter(context, cursor, new MyClickListener());

如何从ListView项更新SQLite行？

1 个答案: