如何从活动到类databasehelper获取价值？

Question

这是我的class databasehelper extends SQLiteOpenHelper

public List<Product>getListIndo(){
        Product product = null;
        List<Product>productList = new ArrayList<>();`enter code here`
        openDatabase();
        Cursor cursor = mDatabase.rawQuery("select * from product, null);
        cursor.moveToFirst();
        while (!cursor.isAfterLast()){
            product = new Product(cursor.getInt(0),cursor.getString(1),cursor.getString(2),cursor.getString(3),cursor.getString(4),cursor.getString(5));
            productList.add(product);
            cursor.moveToNext();
        }
        cursor.close();
        closeDatabase();
        return  productList;
    }

Answer 1

您想将哪个值传递给databasehelper？您在sql查询中使用select方法，这意味着从表product中检索不插入的数据。如果您在数据库中插入内容，则必须使用INSERT INTO table_name