Java类-构造函数的最佳做法（android）

Question

I've built a class and would like to include a constructor which will construct the class from a cursor which will point to an SQLite DB.

I also have a database helper class which sits in the same package and has static variables which give labels to the columns in the cursor.

Should I use these references in the the constructor of the class or is that bad practice?

Thanks, m

here is a simple generic example asked for in the comments...

  public class carDbHelper  extends SQLiteOpenHelper{
      public static final int ROW_ID = 0;
      public static final int ROW_TYPE = 1;

      ...// all db helper code omitted

  }


 public class Car{
            private int id; 
            private String type; 

            public Car (Cursor c){
               this.id = c.getInt(carDbHelper.ROW_ID);
               this.id = c.getString(carDbHelper.TYPE_ID);
            }

        //Other code omitted
     }

Answer 1

Either copying object or referencing to object is good, the problem is that you need to control the object life time well.

I personally prefer copying object to referencing it, since it's really hard to know when object starts to exist or destroy if there're many continuous references on the same object.